Novel Virtual Reality App for Training Patients on MRI-guided Radiation Therapy

Purpose

Patients receiving respiratory gated magnetic resonance imaging-guided radiation therapy (MRIgRT) for abdominal targets must hold their breath for ≥25 seconds at a time. Virtual reality (VR) has shown promise for improving patient education and experience for diagnostic MRI scan acquisition. We aimed to develop and pilot-test the first VR app to educate, train, and reduce anxiety and discomfort in patients preparing to receive MRIgRT.

Methods and Materials

A multidisciplinary team iteratively developed a new VR app with patient input. The app begins with minigames to help orient patients to using the VR device and to train patients on breath-holding. Next, app users are introduced to the MRI linear accelerator vault and practice breath-holding during MRIgRT. In this quality improvement project, clinic personnel and MRIgRT-eligible patients with pancreatic cancer tested the VR app for feasibility, acceptability, and potential efficacy for training patients on using breath-holding during MRIgRT.

Results

The new VR app experience was tested by 19 patients and 67 clinic personnel. The experience was completed on average in 18.6 minutes (SD = 5.4) by patients and in 14.9 (SD = 3.5) minutes by clinic personnel. Patients reported the app was "extremely helpful" (58%) or "very helpful" (32%) for learning breath-holding used in MRIgRT and "extremely helpful" (28%) or "very helpful (50%) for reducing anxiety. Patients and clinic personnel also provided qualitative feedback on improving future versions of the VR app.

Conclusion

The VR app was feasible and acceptable for training patients on breath-holding for MRIgRT. Patients eligible for MRIgRT for pancreatic cancer and clinic personnel reported on future improvements to the app to enhance its usability and efficacy.

Stereotactic body radiotherapy with or without selective dismutase mimetic in pancreatic adenocarcinoma: an adaptive, randomised, double-blind, placebo-controlled, phase 1b/2 trial

BACKGROUND

Stereotactic body radiotherapy (SBRT) has the potential to ablate localised pancreatic ductal adenocarcinoma. Selective dismutase mimetics sensitise tumours while reducing normal tissue toxicity. This trial was designed to establish the efficacy and toxicity afforded by the selective dismutase mimetic avasopasem manganese when combined with ablative SBRT for localised pancreatic ductal adenocarcinoma.

METHODS

In this adaptive, randomised, double-blind, placebo-controlled, phase 1b/2 trial, patients aged 18 years or older with borderline resectable or locally advanced pancreatic cancer who had received at least 3 months of chemotherapy and had an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled at six academic sites in the USA. Eligible patients were randomly assigned (1:1), with block randomisation (block sizes of 6-12) with a maximum of 24 patients per group, to receive daily avasopasem (90 mg) or placebo intravenously directly before (ie, within 180 min) SBRT (50, 55, or 60 Gy in five fractions, adaptively assigned in real time by Bayesian estimates of 90-day safety and efficacy). Patients and physicians were masked to treatment group allocation, but not to SBRT dose. The primary objective was to find the optimal dose of SBRT with avasopasem or placebo as determined by the late onset EffTox method. All analyses were done on an intention-to-treat basis. This study is registered with ClinicalTrials.gov, NCT03340974, and is complete.

FINDINGS

Between Jan 25, 2018, and April 29, 2020, 47 patients were screened, of whom 42 were enrolled (median age was 71 years [IQR 63-75], 23 [55%] were male, 19 [45%] were female, 37 [88%] were White, three [7%] were Black, and one [2%] each were unknown or other races) and randomly assigned to avasopasem (n=24) or placebo (n=18); the placebo group was terminated early after failing to meet prespecified efficacy parameters. At data cutoff (June 28, 2021), the avasopasem group satisfied boundaries for both efficacy and toxicity. Late onset EffTox efficacy response was observed in 16 (89%) of 18 patients at 50 Gy and six (100%) of six patients at 55 Gy in the avasopasem group, and was observed in three (50%) of six patients at 50 Gy and nine (75%) of 12 patients at 55 Gy in the placebo group, and the Bayesian model recommended 50 Gy or 55 Gy in five fractions with avasopasem for further study. Serious adverse events of any cause were reported in three (17%) of 18 patients in the placebo group and six (25%) of 24 in the avasopasem group. In the placebo group, grade 3 adverse events within 90 days of SBRT were abdominal pain, acute cholangitis, pyrexia, increased blood lactic acid, and increased lipase (one [6%] each); no grade 4 events occurred. In the avasopasem group, grade 3-4 adverse events within 90 days of SBRT were acute kidney injury, increased blood alkaline phosphatase, haematoma, colitis, gastric obstruction, lung infection, abdominal abscess, post-surgical atrial fibrillation, and pneumonia leading to respiratory failure (one [4%] each).There were no treatment-related deaths but one late death in the avasopasem group due to sepsis in the setting of duodenal obstruction after off-study treatment was reported as potentially related to SBRT.

INTERPRETATION

SBRT that uses 50 or 55 Gy in five fractions can be considered for patients with localised pancreatic ductal adenocarcinoma. The addition of avasopasem might further enhance disease outcomes. A larger phase 2 trial (GRECO-2, NCT04698915) is underway to validate these results.

FUNDING

Galera Therapeutics.

Outcomes of Cytoreductive Stereotactic Body Radiotherapy (SBRT) in Patients with Oligometastatic or Oligoprogressive Dominant Lung Metastases from Colorectal Primary

PURPOSE/OBJECTIVE(S)

Oxaliplatin based systemic therapy regimens have improved the prognosis of patients with colorectal cancer (CRC) and with this, there has been increased interest in the integration of local therapies to oligometastatic and oligoprogressive sites. There is a vast body of literature exploring the benefits of cytoreduction with surgery and stereotactic body radiation therapy (SBRT) approaches. We report our rates of local control (LC) and overall survival (OS) for patients with oligometastatic/progressive CRC with lung metastases treated with SBRT.

MATERIALS/METHODS

Single institution retrospective review of patients diagnosed with oligometastatic or oligoprogressive CRC with dominant metastases to the lungs who were treated with SBRT between September 2009 and December 2022. Oligometastatic disease was defined as newly diagnosed, untreated CRC with up to 5 metastases, up to 3 in one organ. Oligoprogressive disease was defined as CRC with 1 - 2 distant sites that continued to progress on active treatment while the primary site was controlled. Survival was estimated using Kaplan-Meier. Association between local control and patient factors was analyzed using log-rank test.

RESULTS

A total of 84 patients with oligometastatic or oligoprogressive CRC were treated with SBRT to 124 lung lesions. Colon cancer was the primary site for 54 patients with a median age at time of SBRT of 66 years (IQR 57 - 73) and a median tumor diameter of 1.20 cm (IQR 0.93 - 1.90). Rectal cancer was the primary site for 30 patients, median age was 60 years (IQR 49 - 70) and median tumor diameter was 1.10 cm (IQR 0.80 - 1.48). Median dose for the entire cohort was 6000 cGy (range 5000 - 6000) with median number of fractions 5 (range 3 - 5). Median follow-up after SBRT was 24 months. Overall, there were 9 local failures at last follow-up. Almost half (n = 42) of the patients experienced distant recurrence. Median local control (LC) for the entire cohort was not reached, 2-yr LC and 5-yr LC were 94.6% and 85.7% respectively. There were no differences in LC between colon and rectal cancer (p = 0.29). Actuarial median overall survival was 71 months (95% CI 44.3 - 97.7) and 5-yr OS was 50.2%. Due to the small number of events, we were unable to identify patient factors associated with local failure on univariate or multivariate analysis.

CONCLUSION

Cytoreductive SBRT is an effective treatment option for patients with oligometastatic or oligoprogressive CRC with dominant lung metastases offering excellent rates of LC. Most patients failed distantly highlighting the importance of additional systemic therapies.

Adrenal Stereotactic Body Radiation Therapy: Do Dosimetric Factors Predict for Grade 2+ Lymphopenia?

PURPOSE/OBJECTIVE(S)

Recent studies suggest improvement in outcomes in multiple oligometastatic tumor sites with immunotherapy (IO) and radiation therapy (RT). However, RT may induce lymphopenia that can be immunosuppressive and dosimetric consensus is lacking on parameters predicting grade ≥2 lymphopenia. In this study, we evaluated lymphopenia post receipt of stereotactic body RT (SBRT) for adrenal metastases to see if we could identify any modifiable treatment planning factors.

MATERIALS/METHODS

Patients with adrenal oligometastases who were treated with conventional SBRT or MRI-guided (MRgSBRT), had absolute lymphocyte count (ALC) and white blood cell count (WBC) data available within 6 weeks before and after their radiation treatment, and had contouring data available for review were included in this IRB approved retrospective study. Lymphopenia was graded for ALC as: Grade 1 (1.0-0.8 no/ul), Grade 2 (<0.8 - 0.5 no/ul), Grade 3 (<0.5-0.2 no/ul), Grade 4 (<0.2 no/ul). The vertebral bodies (VB), at the level of the planning treatment volume (PTV) and one above and below, and the spleen were contoured. Dosimetric variables of interest included spleen and VB mean dose (Gy) as well as V2.5-20 Gy in 2.5 Gy increments. Regression analyses were used to identify dosimetric variables associated with absolute and relative difference in ALC post-SBRT.

RESULTS

A total of 30 patients were identified with a slight male predominance (N = 17, 57%) and most commonly left adrenal (N = 17) versus right adrenal (N = 10, 33%) or bilateral metastases (N = 3, 10%). Grade 2+ lymphopenia was observed in N = 7 patients pre-SBRT (23%) and N = 17 patients post-SBRT (57%). N = 26 (87%) of the patients had previous chemotherapies and N = 17 (57%) had previous immunotherapy. Multiple primary tumor types were represented with the most common non-small cell lung cancer (N = 14, 47%), followed by melanoma (N = 4, 13%) and small cell lung cancer (N = 3, 10%). Most patients were treated with non-MRgSBRT (N = 19, 63%) vs MRgRT (N = 11, 37%) and all received SBRT in 5 fractions with median dose 50 Gy (Range: 25 - 60 Gy). The median pre-SBRT ALC was 1.13 (Range: 0.39 - 2.96) and median post-SBRT ALC was 0.72 (Range: 0.11 - 4.15). On linear regression analysis, there was no significant association between post SBRT ALC nor lymphopenia grade with splenic or vertebral body dose, treatment laterality, or SBRT dose.

CONCLUSION

In this retrospective series of predominately metastatic lung cancer patients treated with adrenal SBRT, we observed high rates of post SBRT grade 2+ lymphopenia, yet no dosimetric parameter was predictive, not even for left-sided lesions. Future work includes clinical validation of these findings in a larger population, likely with multi-institutional collaboration, and further study of the investigation of the IO/RT sequencing issues in such heavily pre-treated patients.

Borderline Resectable Pancreatic Cancer: Impact on Neoadjuvant Response Post Integration of MRI Guided Adaptive Radiation Therapy

PURPOSE/OBJECTIVE(S)

The optimal neoadjuvant therapy regimen for patients with borderline resectable pancreas cancer (BRPC) remains to be defined, with a recent ALLIANCE study reporting that chemotherapy alone prior to resection is an acceptable standard of care. However, pathologic differences in response between patients receiving chemotherapy alone and chemotherapy with radiation with stereotactic technique is not clear. In this study, we sought to compare differences in pathologic outcomes between patients undergoing surgery in 2018 compared with 2021 at our comprehensive cancer center, after the new data of chemotherapy alone had been reported and after our center integrated stereotactic MRI guided online adaptive radiotherapy (SMART).

MATERIALS/METHODS

Newly diagnosed BRPC patients were included on this IRB approved study if they were treated on our institutional clinical pathway with initial chemotherapy (FOLFIRINOX or Gemcitabine based) followed by 5 fraction stereotactic body radiation therapy (SBRT) with the intention of primary tumor resection. After surgical resection, tumor response was classified by the Tumor Regression Grading (TRG) System of the College of American Pathology on a scale from 0 (complete response) to 3 (poor response).

RESULTS

In 2018 when patients were treated on a conventional Linac, the median SBRT dose was 40.5 Gy compared with 46.1 Gy in 2021 after SMART integration. In 2018, 54 BRPC patients were treated and 52% were explored. Of those, 72% were resected with a 95% (19/20) rate of R0 resection. In 2021, 66 BRPC patients were treated and 45% were explored. Of those, 74% were resected with a 100% (22/22) rate of R0 resection. In 2018, pathological results showed that 55% (11/20) had lymphovascular invasion (LVI) and 90% (18/20) had perineural invasion (PNI) with a median tumor size of 2.5 cm. The average lymph node ratio in 2018 was 0.06 in 2018 and 0.05 in 2021. In 2021, pathological results showed that 36% (8/22) had LVI and 64% (14/22) had PNI with a median tumor size of 2.2 cm. In 2018, 43% of surgeries required portal vein (PV) resection compared with 27% in 2021. In 2018, of those patients who underwent surgery, 65% (13/20) received both chemotherapy and SBRT compared to 10% (2/20) with chemotherapy alone. In 2021, 73% (16/22) received chemotherapy and SBRT prior to surgery compared with 27% (6/22) who received chemotherapy only. Patients who received chemotherapy only (n = 8) had an average TRG of 2.1 compared to the patients receiving combination therapy (29) with an average TRG of 1.8.

CONCLUSION

This data suggests that higher ablative dose delivery with SMART following systemic therapy may be associated with improved pathologic outcomes, with less LVI, PNI, portal vein resection and improved TRG scores. Further prospective study is needed to confirm improved pathologic outcomes with SMART and to optimize patient selection regarding which patients benefit the most from the combination of chemotherapy and SBRT.

Accurate, repeatable, and geometrically precise diffusion-weighted imaging on a 0.35 T magnetic resonance imaging-guided linear accelerator

Background and purpose

Diffusion weighted imaging (DWI) allows for the interrogation of tissue cellularity, which is a surrogate for cellular proliferation. Previous attempts to incorporate DWI into the workflow of a 0.35 T MR-linac (MRL) have lacked quantitative accuracy. In this study, accuracy, repeatability, and geometric precision of apparent diffusion coefficient (ADC) maps produced using an echo planar imaging (EPI)-based DWI protocol on the MRL system is illustrated, and in vivo potential for longitudinal patient imaging is demonstrated.

Materials and methods

Accuracy and repeatability were assessed by measuring ADC values in a diffusion phantom at three timepoints and comparing to reference ADC values. System-dependent geometric distortion was quantified by measuring the distance between 93 pairs of phantom features on ADC maps acquired on a 0.35 T MRL and a 3.0 T diagnostic scanner and comparing to spatially precise CT images. Additionally, for five sarcoma patients receiving radiotherapy on the MRL, same-day in vivo ADC maps were acquired on both systems, one of which at multiple timepoints.

Results

Phantom ADC quantification was accurate on the 0.35 T MRL with significant discrepancies only seen at high ADC. Average geometric distortions were 0.35 (±0.02) mm and 0.85 (±0.02) mm in the central slice and 0.66 (±0.04) mm and 2.14 (±0.07) mm at 5.4 cm off-center for the MRL and diagnostic system, respectively. In the sarcoma patients, a mean pretreatment ADC of 910x10-6 (±100x10-6) mm2/s was measured on the MRL.

Conclusions

The acquisition of accurate, repeatable, and geometrically precise ADC maps is possible at 0.35 T with an EPI approach.

Radioembolization with Yttrium-90 Glass Microspheres as a First-Line Treatment for Unresectable Intrahepatic Cholangiocarcinoma-A Prospective Feasibility Study

PURPOSE

To evaluate the safety and effectiveness of yttrium-90 (90Y) radioembolization as first-line treatment for unresectable intrahepatic cholangiocarcinoma (ICC).

MATERIALS AND METHODS

This prospective study enrolled patients who had never received chemotherapy, liver embolization, and radiation therapy. The tumors were solitary in 16 patients, multiple in 8 patients, unilobar in 14 patients, and bilobar in 10 patients. Patients underwent transarterial radioembolization with 90Y-labeled glass microspheres. The primary end point was hepatic progression-free survival (HPFS). Secondary end points were overall survival (OS), tumor response, and toxicity.

RESULTS

Twenty-four patients (age, 72.3 years ± 9.3; 12 women) were included in the study. The median delivered radiation dose was 135.5 Gy (interquartile range, 77.6 Gy). The median HPFS was 5.5 months (95% CI, 3.9-7.0 months). Analysis failed to identify any prognostic factor associated with HPFS. Imaging response at 3 months showed 56% disease control, and the best radiographic response was 71% disease control. The median OS from the radioembolization treatment was 19.4 months (95% CI, 5.0-33.7). Patients with solitary ICC had significantly longer median OS than patients with multifocal ICC: 25.9 months (95% CI, 20.8-31.0 months) versus 10.7 months (95% CI, 8.0-13.4 months) (P = .02). Patients with progression on the 3-month imaging follow-up had significantly shorter median OS than patients who had stable disease at 3 months: 10.7 months (95% CI, 0.7-20.7 months) versus 37.3 months (95% CI, 16.5-58.1 months) (P = .003). Two (8%) Grade 3 toxicities were reported.

CONCLUSIONS

First-line treatment of ICC with radioembolization showed promising OS and minimal toxicity, especially in patients with solitary tumor. Radioembolization may be considered as a first-line treatment option for unresectable ICC.

Induction Fluorouracil-Based Chemotherapy and PET-Adapted Consolidation Chemoradiation with Esophagectomy for High-Risk Gastroesophageal Adenocarcinoma

Background: Neoadjuvant chemoradiation with esophagectomy is standard management for locally advanced esophageal adenocarcinoma. Induction chemotherapy with a tailored approach to chemoradiation based on metabolic response to therapy on PET was explored as an alternative strategy in the CALGB 80803 trial. We sought to describe real-world institutional experience implementing this approach outside of a clinical trial. Methods: Patients who were treated with induction fluorouracil-leucovorin-oxaliplatin (FOLFOX) or fluorouracil-leucovorin-oxaliplatin-docetaxel (FLOT) with tailored chemoradiation based on PET response and subsequent esophagectomy were identified from a prospectively maintained database. Primary outcomes were pathologic complete response (pCR) and overall survival (OS) following completion of all therapy. Results: There were 35 patients who completed induction chemotherapy, chemoradiation, and esophagectomy. Thirty-three completed restaging PET following induction chemotherapy with metabolic response seen in 76% (n = 25/33). The pCR rate was 31% (n = 11/35) and the ypN0 rate was 71% (n = 25/35). Among the patients who demonstrated metabolic response to induction FOLFOX/FLOT and subsequently continued fluorouracil-based chemoradiation, the pCR rate was 39% (n = 9/23). The rate of pathologically negative lymph nodes in this group was high (n = 19/23, 83%) with 100% R0 resection rate (n = 23/23). With the median follow-up of 43 months, the median OS was not reached for this group and was significantly longer than the OS for the remainder of the cohort (p = 0.027, p = 0.046 adjusted for clinical stage). Conclusions: Induction FOLFOX/FLOT chemotherapy with evaluation of sensitivity via metabolic response and tailored chemoradiation seems to lead to high pCR and ypN0 rates in high-risk patients with adenocarcinoma of the esophagus and GE junction. This approach in clinical practice seems to recapitulate encouraging results in clinical trials.

Neoadjuvant chemotherapy and stereotactic body radiation therapy for borderline resectable pancreas adenocarcinoma: influence of vascular margin status and type of chemotherapy

BACKGROUND

The influence of chemotherapy type and vascular margin status after sequential chemotherapy and stereotactic body radiation therapy (SBRT) for borderline resectable pancreatic cancer (BRPC) is unknown.

METHODS

A retrospective review was performed on BRPC patients treated with chemotherapy and 5-fraction SBRT from 2009 to 2021. Surgical outcomes and SBRT-related toxicity were reported. Clinical outcomes were estimated by Kaplan-Meier with log rank comparisons.

RESULTS

A total of 303 patients received neoadjuvant chemotherapy and SBRT to a median dose of 40 Gy prescribed to the tumor-vessel interface and median dose of 32.4 Gyto 95% of the gross tumor volume. One hundred and sixty-nine patients (56%) were resected and benefited from improved median OS (41.1 vs 15.5 months, P < 0.001). Close/positive vascular margins were not associated with worse OS or FFLRF. Type of neoadjuvant chemotherapy did not influence OS for resected patients, but FOLFIRINOX was associated with improved median OS in unresected patients (18.2 vs 13.1 months, P = 0.001).

CONCLUSION

For BRPC, the effect of a positive or close vascular margin may be mitigated by neoadjuvant therapy. Shorter duration neoadjuvant chemotherapy as well as the optimal biological effective dose of radiotherapy should be prospectively explored.

Multi-Institutional Outcomes of Patients Aged 75 years and Older With Pancreatic Ductal Adenocarcinoma Treated With 5-Fraction Ablative Stereotactic Magnetic Resonance Image-Guided Adaptive Radiation Therapy (A-SMART)

PURPOSE

Treatment options for pancreatic ductal adenocarcinoma (PDAC) are commonly limited for patients with advanced age due to medical comorbidities and/or poor performance status. These patients may not be candidates for more aggressive chemotherapy regimens and/or surgical resection leaving few, if any, other effective treatments. Ablative stereotactic MRI-guided adaptive radiation therapy (A-SMART) is both efficacious and safe for PDAC and can achieve excellent long-term local control, however, the appropriateness of A-SMART for elderly patients with inoperable PDAC is not well understood.

METHODS

A retrospective analysis was performed of inoperable non-metastatic PDAC patients aged 75 years or older treated on the MRIdian Linac at 2 institutions. Clinical outcomes of interest included overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional (LRC). Toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE, v5).

RESULTS

A total of 49 patients were evaluated with a median age of 81 years (range, 75-91) and a median follow-up of 14 months from diagnosis. PDAC was classified as locally advanced (46.9%), borderline resectable (36.7%), or medically inoperable (16.3%). Neoadjuvant chemotherapy was delivered to 84% of patients and all received A-SMART to a median 50 Gy (range, 40-50 Gy) in 5 fractions. 1 Year LRC, PFS, and OS were 88.9%, 53.8%, and 78.9%, respectively. Nine patients (18%) had resection after A-SMART and benefited from PFS improvement (26 vs 6 months, P = .01). ECOG PS <2 was the only predictor of improved OS on multivariate analysis. Acute and late grade 3 + toxicity rates were 8.2% and 4.1%, respectively.

CONCLUSIONS

A-SMART is associated with encouraging LRC and OS in elderly patients with initially inoperable PDAC. This novel non-invasive treatment strategy appears to be well-tolerated in patients with advanced age and should be considered in this population that has limited treatment options.

A Practical Workflow for Magnetic Resonance-Guided Stereotactic Body Radiation Therapy to the Pancreas

The increased adoption of stereotactic body radiation therapy has allowed for delivery of higher doses, potentially associated with better outcomes but at the risk of higher toxicity. The intimate association of radiosensitive organs at risk (eg, stomach, duodenum, bowel) has historically limited the delivery of ablative doses to the pancreas. The advent of magnetic resonance-guided radiation therapy with improved soft-tissue contrast allows for gated delivery without an internal target volume and online adaptive replanning to maximize the therapeutic ratio. Patient selection requires additional resources, including increased patient on-table time, physician time, and physics support. Within our center's workflow, integrating an educational video at consultation as well as optimizing biofeedback mechanisms have significantly improved the experience for our patients.

Ablative 5-Fraction Stereotactic MRI-Guided Adaptive Radiotherapy for Oligometastatic Pancreatic Adenocarcinoma

INTRODUCTION

Metastatic pancreatic ductal adenocarcinoma (PDAC) carries a poor prognosis and significant morbidity from local tumor progression. We investigated outcomes among oligometastatic PDAC patients treated with stereotactic magnetic resonance image-guided ablative radiotherapy (SMART) to primary disease.

METHODS

We performed a retrospective multi-institutional analysis of oligometastatic PDAC at diagnosis or with metachronous oligoprogression during induction chemotherapy treated with primary tumor SMART. Outcomes of interest included overall survival (OS), progression-free survival (PFS), freedom from locoregional failure (FFLRF), and freedom from distant failure (FFDF). Acute and late toxicity were reported and in exploratory analyses patients were stratified by the number of metastases, SMART indication, and addition of metastasis-directed therapy.

RESULTS

From 2019 to 2021, 22 patients with oligometastatic PDAC (range: 1-6 metastases) received SMART to the primary tumor with a median follow-up of 11.2 months from SMART. Nineteen patients had de novo synchronous metastatic disease and three had metachronous oligoprogression. Metastasis location most commonly was liver only (40.9%), multiple organs (27.3%), lungs only (13.6%), or abdominal/pelvic nodes (13.6%). All patients received either FOLFIRINOX (64%) or gemcitabine/nab-paclitaxel (36%) followed by SMART (median 50 Gy, 5 fractions) for local control (77%), pain control (14%), or local progression (9%). Additionally, 41% of patients received other metastasis-directed treatments. The median OS from diagnosis and SMART was 23.9 months and 11.6 months, respectively. Calculated from SMART, the median PFS was 2.4 months with 91% of patients having distant progression, and 1-year local control was 68. Two patients (9%) experienced grade 3 toxicities, gastric outlet obstruction, and gastrointestinal bleed without grade 4 or 5 toxicity.

CONCLUSION

There was minimal morbidity of local disease progression after SMART in this cohort of oligometastatic PDAC. As systemic therapy options improve, additional strategies to identify patients who may derive benefits from local consolidation or metastasis-directed therapy are needed.

Developing a Dedicated Leadership Curriculum for Radiation Oncology Residents

The increasing complexity of healthcare emphasizes the need for continued physician leadership and leadership training. This study aims to determine baseline attitudes toward the perceptions and utility of a leadership development curriculum (LDC) for radiation oncology (RO) residents. A novel longitudinal LDC was implemented for RO residents at our institution from 2018 to 2019. Prior to the curriculum, current and past residents in our institution's RO residency program were surveyed on their attitudes towards leadership in healthcare, emotional intelligence competencies, and leadership training interests. After the completion of the LDC, a post-curriculum survey was forwarded to current residents. The response rate was 84% (21 of 24) for the baseline survey and 90% (9 of 10) for the post-curriculum survey. Having a leadership training curriculum during residency was rated as extremely useful, with top training interests involving leading clinical teams, effective communication strategies, and conflict management. After the LDC, the residents reported high satisfaction with the curriculum and utilization of leadership training into their daily work. Our LDC demonstrates significant potential to engage trainees and improve their leadership skills at the graduate medical education level.

The effect of histologic grade on neoadjuvant treatment outcomes in esophageal cancer

BACKGROUND AND OBJECTIVES

The gold standard for locoregional esophageal cancer (LEC) treatment includes preoperative chemoradiation and surgical resection, with possible perioperative or adjuvant systemic therapy. With few data associating histologic grade and prognosis in LEC patients receiving neoadjuvant chemoradiation followed by resection, we seek to evaluate this association.

METHODS

Our institutional esophagectomy database between 1999 and 2019 was queried, selecting esophageal adenocarcinoma patients who completed neoadjuvant therapy (NAT), followed by esophagectomy. Propensity-score matching of low- and high-histologic grade groups was performed to assess survival metrics using initial clinical grade (cG) and final pathologic grade (pG). We performed a multivariable logistic regression to study predictors of pathologic complete response as a secondary objective.

RESULTS

A total of 518 patients met the inclusion criteria. Kaplan-Meier analysis of the matched dataset showed no difference in initial or 5-year recurrence-free survival or overall survival (OS) between cG1 and cG2 versus cG3 based on original grade. When matched according to pG, cG1-2 had improved median survival parameters compared to cG3, with 5-year OS for cG1-2 of 45% versus 27% (p = 0.001). Higher pG, pathologic N stage, and poor response to NAT are predictors of poor survival.

CONCLUSION

Patients with post-NAT pG1-2 demonstrated improved survival. Integrating histologic grade into postneoadjuvant staging may be warranted.

Core homologous recombination mutations and improved survival in nonpancreatic GI cancers

663

Background: GI malignancies continue to be a major cause of cancer related deaths, despite advances in therapy options. In pancreatic cancer, the presence of homologous recombination mutations (HRM) has been shown to confer increased sensitivity to platinum chemotherapy. However, the role of HRM mutations in other GI cancers remains to be determined. The focus of this study is to evaluate the prognostic nature of core and noncore HRM in nonpancreatic GI cancers. Additionally, we aim to understand the predictive nature of these mutations related to platinum exposure. Methods: This was a retrospective review of patients at Moffitt Cancer Center with a primary stage IV nonpancreatic GI cancer treated with platinum therapy. All patients had next generation sequencing and were in the Clinical Genomics Action Committee database between 1/1/2013 and 11/1/2020. All patients had either a core HRM (BRCA1, BRCA2, PALB2) or noncore HRM (such as ATM, ATR, BARD1, BRIP1, FANCA, NBN, and RAD51). Patients were grouped into core HRM vs. noncore HRM. Response was stratified between responders (complete response and partial response) vs. non responders (stable disease and progressive disease), based on RECIST criteria. Progression free survival and overall survival were estimated using Kaplan-Meier method, and the log-rank test was used to assess the difference in progression free survival (PFS) and overall survival (OS) by HRM status and type of platinum therapy used. Results: There were 72 patients included in the study: the majority of patients were male (65.3%) and Caucasian (87.5%). Twenty-one (29.2%) patients had a core HRM and 51 (70.8%) had a noncore HRM. There was no significant difference in response rate between patients with core HRM and patients with noncore HRM for evaluable patients (n = 66): 20.0% of patients with core HRM vs. 21.7% of patients with noncore HRM demonstrated a response to platinum therapy (p = 0.41). An improved OS was noted for patients with core HRM vs. those with noncore HRM at 68.9 vs. 24.3 months (p = 0.019). An improved PFS was also seen in patients with core HRM at 10.4 months vs. 6.3 months with noncore HRM (p = 0.027). There was no difference in PFS based on type of platinum therapy used (oxaliplatin vs. carboplatin vs. cisplatin), while an improved OS was noted for patients treated with oxaliplatin vs. carboplatin vs. cisplatin at 43.1 vs. 28.2 vs. 16.0 months (p = 0.011). Conclusions: Our study demonstrated that in stage IV nonpancreatic GI malignancies treated with platinum therapy, patients with core HRM had a greater OS and PFS compared to those with noncore HRM, suggesting a potential prognostic and predictive role of these mutations. Further studies are needed to confirm our findings.

Association of BRAF V600E mutation with survival in patients with metastatic mismatch repair-deficient colorectal cancer

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Background: Colorectal cancer (CRC), while one of the most common cancer diagnoses, can behave heterogeneously based on molecular characteristics. A subset of patients (pts) with CRC are characterized with mismatch repair deficiency (MMR-d), these pts exhibit encouraging responses to immunotherapy. The predictive nature of various factors, such as BRAF status, age, and MMR-D protein loss type, have been investigated in pts with MMR-d CRC. However, the prognostic role of these factors has not been well established. The purpose of this study was to identify characteristics that influence survival in MMR-d mCRC. Methods: This study evaluated pts with MMR-d mCRC in the Flatiron database. Overall survival (OS) was determined from date of diagnosis of stage IV disease to date of death and stratified based on age greater than or less than 50 years, BRAF mutation status, RAS mutation status, and type of MMR gene loss. For statistical analysis, the Chi-Square test was implemented to determine the prognostic significance of clinical and molecular features. Univariate and multivariate analyses were determined through the Cox regression model. Results: There were 1,101 pts in the study. The majority of pts were older than 50 (79.7%), Caucasian (75%), and had ECOG 0-1 (83.4%). Among the 803 pts with known BRAF status, 44.3% (n=356) had BRAF V600E mutation and 55.7% (n=447) were BRAF wildtype. Pts with BRAF V600E mutation had OS of 18.9 months vs. 33.2 months for pts with wild type BRAF (HR 1.52, 95% CI: 1.25-1.86, p<0.001). Pts older than 50 had a lower median OS vs. those who were ≤50 at 21.4 months vs. 38.7 months (HR 1.66, 95% CI: 1.33-2.07, p<0.001). When comparing MSH2/MSH6 mutations to MLH1/PMS2, a trend towards improved OS was seen with median survival of 35.2 months vs. 22.7 months, respectively (HR 0.79, 95% CI: 0.61-1.02, p=0.067). On multivariate analysis, BRAF mutation and older age continued to be associated with differences in survival, while KRAS mutation and specific MMR gene loss did not. Conclusions: BRAF V600E mutation and age greater than 50 are associated with decreased survival for pts with MMR-D mCRC. KRAS mutations and specific MMR alterations are not associated with differences in survival.

Pathological outcomes of pancreatic adenocarcinoma (PA) after preoperative high biological effective dose (BED) magnetic resonance image-guided radiation therapy (MRgRT)

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Background: Pre-operative radiotherapy (RT) for PA has the potential to reduce positive surgical margin rates and increase pathologic tumor response, which has been associated with improved survival. Increasing the BED can improve local control and overall survival for patients with unresectable PA. Use of stereotactic body radiation therapy (SBRT) to achieve a higher BED has been limited by toxicity to adjacent radiosensitive structures, but this can be mitigated by MRgRT. We describe our use of MRgRT prior to potentially curative resection of localized PA. Methods: We performed a single institution retrospective analysis of all patients with localized PA who received high BED SBRT on the MR Linac followed by surgical resection with curative intent. Toxicity was evaluated according to Common Terminology Criteria for Adverse Events, version 5.0. Tumor response was evaluated according to the College of American Pathologists tumor regression grading criteria (CAP-TRG), ranging from CAP 0 indicating pathologic complete response to CAP grade 3 indicating no response. Ordinal logistic regression model was used to assess the association between time from RT to surgery and TRG. Follow up included MRI or CT scans at least every three months. Results: We analyzed 26 patients with borderline resectable (80.8%), locally advanced (11.5%), and resectable (7.7%) tumors who received high BED MRgRT followed by surgical resection. Median age at diagnosis was 68 years (34 - 86). Most patients received chemotherapy (80.8%) prior to RT, with 81% of these receiving FOLFINIRNOX and 19% receiving gemcitabine/nab-paclitaxel. All patients received MR-guided high BED SBRT to a median dose of 50 Gy (40 - 50) in 5 fractions. On-table adaptive replanning was performed in 88% of patients, with 74% having all 5 fractions adapted. No acute grade 2+ toxicity associated with RT was observed. The median time to resection was 50 days (37 – 115), and the procedure types included: Whipple (69%), distal (23%), or total pancreatectomy (8%). The R0 resection rate was 96% and no perioperative deaths occurred within 90 days. Complete (0) or near-complete (1) pathologic response was observed in 35% of cases and the time from RT to surgery was positively associated with TRG (R2= 0.22, p = 0.0003). The median follow-up after RT was 16.5 months (3.9- 26.2) during which 9 patients recurred, and 3 patients died of disease. The derived median progression-free survival from RT was 13.2 months. Conclusions: These initial pathology outcomes following high BED MR-guided SBRT are encouraging and suggest that the time from SBRT to surgical resection is associated with response. This finding is consistent with results from other preoperative GI tumor sites and results from prospective studies using high BED SBRT with MRI guidance in combined modality therapy against PA are eagerly awaited.

Multi-institutional outcomes of patients aged 75 years and older with pancreatic ductal adenocarcinoma treated with ablative 5-fraction stereotactic magnetic resonance image-guided adaptive radiation therapy (SMART)

569

Background: Dose escalated radiation therapy (RT) may improve long-term clinical outcomes compared to standard radiation dose for patients with initially inoperable pancreatic ductal adenocarcinoma (PDAC). Favorable outcomes have recently been reported of ablative stereotactic magnetic resonance image-guided adaptive radiation therapy (SMART) delivered in 5 fractions. The appropriateness of ablative SMART inoperable PDAC patients with advanced age (>75 years) is not well understood. Methods: A retrospective analysis was performed of inoperable non-metastatic PDAC patients aged 75 year or older treated on a 0.35T-MR Linac at two institutions. Patients were excluded who did not have at least 3 months follow up after SMART. Fiducial markers were not used. Treatment delivery was typically in breath hold. Most (65.3%) were treated to gross disease only without elective coverage. On-table adaptive replanning was performed for each fraction if needed, primarily to account for interfraction anatomic changes and ensure all organ-at-risk (OAR) constraints were met. Treatment response was defined using RECIST 1.1 criteria and CTCAE v5 criteria was used to assess toxicity. Results: 49 patients were evaluated with median age of 81 years (range 75-91). ECOG performance status (PS) was 0-1 in 89.8%. PDAC was locally advanced (46.9%), borderline resectable (36.7%), or medically inoperable (16.3%). Median CA19-9 at diagnosis was 235.8 U/mL. Most received induction chemotherapy (83.7%), usually gemcitabine/nab-paclitaxel (63.3%) and rarely FOLFIRINOX (12.2%), for a median 3.2 months. Median prescribed dose was 50 Gy (range, 40-50 Gy). Surgery was performed in 18.4% after a median 10 weeks from SMART, all having negative margins. Median follow-up was 14 months from diagnosis. Median and 1-year local control (LC) was 29 months and 88.9%, respectively. Median and 1-year progression free survival (PFS) was 13 months and 53.8%, respectively. Median and 1-year estimated overall survival (OS) was 23 months and 78.9%, respectively. ECOG PS < 2 was the only significant predictor of improved OS on multivariate analysis with a trend towards significance for induction chemotherapy >3 months. Acute and late grade 3+ toxicity rates were 8.2% and 4.1%, respectively. Conclusions: Ablative 5-fraction SMART is associated with encouraging long-term LC and OS among elderly patients with PDAC. This novel treatment strategy is noninvasive, does not require anesthesia, is remarkably well tolerated among patients with advanced age despite the high prescription dose, and therefore should be strongly considered especially among older patients who have limited treatment options.

Delta radiomics analysis of Magnetic Resonance guided radiotherapy imaging data can enable treatment response prediction in pancreatic cancer

Background

Magnetic Resonance Image guided Stereotactic body radiotherapy (MRgRT) is an emerging technology that is increasingly used in treatment of visceral cancers, such as pancreatic adenocarcinoma (PDAC). Given the variable response rates and short progression times of PDAC, there is an unmet clinical need for a method to assess early RT response that may allow better prescription personalization. We hypothesize that quantitative image feature analysis (radiomics) of the longitudinal MR scans acquired before and during MRgRT may be used to extract information related to early treatment response.

Methods

Histogram and texture radiomic features (n = 73) were extracted from the Gross Tumor Volume (GTV) in 0.35T MRgRT scans of 26 locally advanced and borderline resectable PDAC patients treated with 50 Gy RT in 5 fractions. Feature ratios between first (F1) and last (F5) fraction scan were correlated with progression free survival (PFS). Feature stability was assessed through region of interest (ROI) perturbation.

Results

Linear normalization of image intensity to median kidney value showed improved reproducibility of feature quantification. Histogram skewness change during treatment showed significant association with PFS (p = 0.005, HR = 2.75), offering a potential predictive biomarker of RT response. Stability analyses revealed a wide distribution of feature sensitivities to ROI delineation and was able to identify features that were robust to variability in contouring.

Conclusions

This study presents a proof-of-concept for the use of quantitative image analysis in MRgRT for treatment response prediction and providing an analysis pipeline that can be utilized in future MRgRT radiomic studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01957-5.

Overcoming resistance to anti-PD-1 with tumor agnostic NBTXR3: From bench to bed side

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Background: Despite recent advances, resistance to immune checkpoint inhibitors (ICI), observed in over 80% of treated patients, is currently the main challenge in immuno-oncology. Intense efforts are being made to identify combination therapies that could improve ICI response rates. NBTXR3, a novel radioenhancer administered by direct intratumoral injection (ITI), is designed at the nanoscale to increase radiation therapy (XRT) dose deposit within tumor cells and subsequent tumor cell killing, without increasing toxicity to surrounding healthy tissue. Here we present evidence that NBTXR3 activated by XRT primes the immune system, producing an anti-tumor response, including activation of the cGAS-STING pathway, that overcomes anti-PD-1 resistance both in mice models and patients. Methods: Abscopal assays were conducted in immunocompetent mice. Anti-PD-1 sensitive or resistant tumor cell lines, were injected in both flanks of mice. Intratumoral injection of NBTXR3 (or vehicle) followed by XRT was performed in right flank (primary) tumors only. Some mice also received anti-PD-1 injections. Tumor growth was monitored, and tumor immune cell infiltrates analyzed by immunohistochemistry (IHC). Separately, in the phase II/III randomized Act.in.Sarc [NCT02379845] trial patients with locally advanced soft tissue sarcoma (STS) received either NBTXR3+XRT or XRT alone followed by tumor resection. Pre- and post-treatment tumor samples from patients in both groups were analyzed by IHC and Digital Pathology for immune biomarkers. The safety and efficacy (RECIST 1.1/iRECIST) of NBTXR3 plus stereotactic body radiotherapy (SBRT) in combination with anti-PD-1 is being evaluated in three cohorts of patients with advanced cancers [NCT03589339]. Results: Pre-clinical studies demonstrated that NBTXR3+XRT induces an immune response not observed with XRT alone and enhances systemic control. IHC showed significant increase of CD8+ T-cell infiltrates in both NBTXR3+XRT treated and untreated tumors compared to XRT alone. Similarly, increased CD8+ T-cell and decreased FOXP3+ Treg density (pre- vs post-treatment) was observed in tumor tissues from STS patients treated with NBTXR3+XRT. Furthermore, NBTXR3+XRT in combination with anti-PD-1 improved local and systemic control in mice bearing anti-PD-1 resistant lung tumors, as well as reduced the number of spontaneous lung metastases. Preliminary efficacy data from the first in human trial of NBTXR3+XRT in combination with anti-PD-1 showed tumor regression in the majority of patients (8/9). Of note, tumor regression was observed in 6/7 pts who had progressed on prior anti-PD-1. Conclusions: The clinical efficacy of NBTXR3+XRT has been demonstrated as a single agent. We now demonstrate that it potentiates anti-PD-1 treatment to overcome resistance mechanisms. These results highlight the potential of NBTXR3+XRT to positively impact the immuno-oncology field. Clinical trial information: NCT03589339.

A phase I trial evaluating NBTXR3 activated by radiotherapy in combination with nivolumab or pembrolizumab in patients with advanced cancers

2590

Background: Immune checkpoint inhibitors (ICIs) targeting PD-1 are an effective treatment for a variety of cancers. However, the majority of patients (pts) exhibit resistance to ICIs. Overcoming this resistance represents a major challenge in immuno-oncology. Emerging evidence suggests radiation therapy (RT) produces an immunomodulatory effect that may act synergistically with ICIs. However, RT dose and ultimate efficacy are limited by toxicity to surrounding healthy tissues. NBTXR3, a novel radioenhancer administered by direct intratumoral injection (ITI), is designed at the nanoscale to increase RT dose deposit within tumor cells and subsequent tumor cell killing, without increasing toxicity to surrounding healthy tissue. Preclinical data suggest NBTXR3/RT can trigger a local and systemic anti-tumor immune response and overcome anti-PD-1 resistance. NBTXR3/RT combined with anti-PD-1 may prime the immune system to increase the proportion of ICI responders, or convert ICI non-responders to responders. Methods: This is a multicenter, open-label, phase I trial [NCT03589339] to evaluate NBTXR3/RT/anti-PD-1 in 3 cohorts: (1) Locoregional recurrent or recurrent and metastatic head and neck squamous cell carcinoma (HNSCC) amenable to HN re-irradiation, and metastases from any primary cancer eligible for anti-PD-1 (nivolumab or pembrolizumab) treatment specifically localized in the lung (2) or liver (3), respectively. Stereotactic body RT (SBRT) is delivered at tumor-site selective doses per standard practice. The primary objective is NBTXR3/RT/anti-PD-1 recommended phase 2 dose in each cohort. Secondary objectives are anti-tumor response (objective response rate), safety and feasibility of NBTXR3 injection. Results: Nine pts have been treated: 3 HNSCC, 4 lung, 2 liver. 7/9 pts were anti-PD-1 non-responders. Overall tumor regression was observed in 8/9 pts. NBTXR3/RT/anti-PD-1 resulted in tumor regression in 6/7 pts who had progressed on prior anti-PD-1. A complete response in the injected lymph node lasting over 1 year was observed in 1 anti-PD-1 naïve pt. 2 SAEs related to anti-PD-1 and possibly related to NBTXR3 (G5 pneumonitis, G4 hyperglycemia) were observed in 1 anti-PD-1 naïve HNSCC pt and considered DLTs. This pt also experienced 2 other SAEs related to anti-PD-1 (G4 diabetic ketoacidosis, G4 acute kidney injury). SBRT-related safety profile was as expected. Updated results will be presented. Conclusions: Data from this first-in-human phase I trial evaluating NBTXR3/RT/anti-PD-1 in pts with advanced cancers, show NBTXR3 ITI is feasible and well-tolerated. NBTXR3/RT/anti-PD-1 demonstrated promising signs of efficacy. Of particular interest, NBTXR3/RT can overcome ICI resistance in pts having progressed on prior anti-PD-1, supporting further development of NBTXR3 in combination with anti-PD-1 as well as other ICIs. Clinical trial information: NCT03589339.

Pretreatment CT and PET radiomics predicting rectal cancer patients in response to neoadjuvant chemoradiotherapy

Background

The purpose of this study was to characterize pre-treatment non-contrast computed tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) based radiomics signatures predictive of pathological response and clinical outcomes in rectal cancer patients treated with neoadjuvant chemoradiotherapy (NACR T).

Materials and methods

An exploratory analysis was performed using pre-treatment non-contrast CT and PET imaging dataset. The association of tumor regression grade (TRG) and neoadjuvant rectal (NAR) score with pre-treatment CT and PET features was assessed using machine learning algorithms. Three separate predictive models were built for composite features from CT + PET.

Results

The patterns of pathological response were TRG 0 (n = 13; 19.7%), 1 (n = 34; 51.5%), 2 (n = 16; 24.2%), and 3 (n = 3; 4.5%). There were 20 (30.3%) patients with low, 22 (33.3%) with intermediate and 24 (36.4%) with high NAR scores. Three separate predictive models were built for composite features from CT + PET and analyzed separately for clinical endpoints. Composite features with α = 0.2 resulted in the best predictive power using logistic regression. For pathological response prediction, the signature resulted in 88.1% accuracy in predicting TRG 0 vs. TRG 1-3; 91% accuracy in predicting TRG 0-1 vs. TRG 2-3. For the surrogate of DFS and OS, it resulted in 67.7% accuracy in predicting low vs. intermediate vs. high NAR scores.

Conclusion

The pre-treatment composite radiomics signatures were highly predictive of pathological response in rectal cancer treated with NACR T. A larger cohort is warranted for further validation.

The effect of gender on outcomes in esophageal cancer

170

Background: Few epidemiological studies address differences in outcomes by gender in locoregional esophageal cancer (LEC) for which the current standard of care is chemoradiation followed by surgical resection. Although male gender is associated with the majority of LEC cases, we sought to determine if gender could impact clinical presentation as well as surgical and oncologic outcomes in our single institution 20 year experience. Methods: A retrospective query of our institution’s IRB-approved database of patients that had surgical therapy between 2008 and 2019 for esophageal cancer (EC) was performed. Patients were stratified by gender and analyzed based on characteristics such as tumor histology, tumor location, clinical stage at presentation, age at diagnosis, receipt of neoadjuvant therapy, surgical intent, surgical complications, length of post-operative hospital stay, response to neoadjuvant therapy, final pathology, and recurrence. Chi-square, ANOVA and Kaplan Meier survival analysis were performed on the previously defined groups. Results: The cohort studied included 1180 patients with resection for EC. Of those, 1005 (85.2%) had adenocarcinoma, 145 (12.3%) had squamous cell cancer (SCC), 10 (0.8%) had adenosquamous carcinoma, and 20 (1.7%) had other histological variants. There were 985 (83.5%) male patients and 195 (16.5%) female patients. SCC was more common in females (29.2% in females vs. 8.9% in males, p = 0.000) and females tended to have tumor location in the upper thoracic esophagus more often (4.7% in females vs. 0.9% of males, p = 0.000). Additionally, females developed surgical complications more often than males (72.2% vs. 64.7%, p = 0.045). Staging at diagnosis (p = 0.508), receipt of neoadjuvant treatment (p = 0.676), and age at diagnosis (65.3 years in males vs. 66.3 years in females, p = 0.934) had no association with gender. Response to neoadjuvant therapy (p = 0.157) and cancer recurrence (p = 0.434) did not have significant associations with gender. The median overall survival was not statistically significantly different but trended to be longer for females (73.4 months in females [95% CI: 51.5-95.4] vs. 47.0 months in males [95% CI: 39.6-54.5], p = 0.160). Conclusions: Based on our high-volume cancer center study, female patients were more likely to have SCC, upper thoracic esophageal lesions, and surgical complications following resection. While univariate analysis did not demonstrate significant differences in overall survival between genders, there are plans to report additional data after controlling for other variables. Further studies are warranted to validate these findings, given the potential for higher prioritization of an organ preservation approach for this patient population.

Early outcomes of irreversible electroporation after stereotactic body radiation therapy for the treatment of locally advanced pancreatic adenocarcinoma (LAPC): A matched pair analysis

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Background: Outcomes remain poor for those diagnosed with unresectable pancreatic cancer. SBRT and IRE have independently demonstrated high rates of local control and minimal toxicity for patients with locally advanced pancreatic cancer (LAPC). Data is limited regarding safety and efficacy in the sequential use of both therapies. Materials and Methods: A single institution retrospective matched cohort analysis was performed for patients with non-metastatic pancreatic cancer treated with induction chemotherapy and SBRT followed by IRE, compared with patients of the same cohort who did not receive IRE. Patients were paired based on age, tumor stage, GTV D95, CA19-9 prior to SBRT, and chemotherapy type to mitigate selection bias in surgical candidates. Overall survival (OS), progression free survival (PFS), freedom from local failure (FFLF) and freedom from distant failure (FFDF) were the primary outcomes compared via Kaplan-Meier survival analysis with log-rank methods. Results: From July, 2014 to February, 2020 17 patients received SBRT followed by IRE. These patients were matched with 17 patients who received SBRT from January, 2012 to March, 2019. Most patients received neoadjuvant FOLFIRINOX (82.4%) and were AJCC 8 stage III (79.4%). Median age of the overall cohort was 65.5 years and 50% were male. Median dose delivered to 95% of gross tumor volume was 32.61 Gy, and median pre SBRT CA19-9 value was 70.5 U/mL. There were no statistically significant differences in matched characteristics between the two cohorts. Among the SBRT+IRE, the median time between IRE and SBRT was 66 days (range:49-467 days). The median OS, PFS, FFLF, and FFDF for IRE+SBRT vs. SBRT alone from SBRT was 10.8 vs 15.1 months, 9.6 vs. 15.3 months, 15.7 vs. 15.3 months, 15.9 vs. 14.4 months respectively (all P > .10). 11 patients in the entire cohort experienced toxicity as a result of their radiation therapy (35%), with one G3 GIB and one patient experiencing G3 abdominal pain. Among the 17 patients who underwent IRE, nine patients experienced toxicity (53%). Most of these events were G3, with two G4 intestinal bleeds. There was zero mortality in the 90 day period post operatively. Conclusions: In a retrospective cohort,non-selective delivery ofIRE afterSBRT demonstrated no oncological benefit for patients with unresectable pancreatic adenocarcinoma compared to only SBRT. Compared to historical experiences of IRE alone, there was no increase in overall toxicity with the combination of SBRT and IRE. The optimal timing, sequencing, and indications for IRE and SBRT in LAPC remain unknown and are best assessed prospectively. [Table: see text]

Comprehensive evaluation of genomic alterations in patients with gastric and gastroesophageal adenocarcinoma stratified according to TP53 mutation status

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Background: Gastric (GC) and gastroesophageal adenocarcinomas (GEA) are molecularly diverse. Molecular biomarkers of clinical significance have been identified that impact treatment decision making. TP53 is the most frequently altered gene with approximately 50% of patients harboring mutations. However, TP53 mutations have not yet been confirmed as a target of therapeutic benefit. This study aimed to identify distinct genomic alterations that are dominant in TP53 mutated (MUT) versus wild-type (WT) GC and GEA in order to elucidate alternative therapeutic targets within these subsets. Methods: De-identified data for 3741 patients with GC and GEA was obtained from Foundation Medicine. The data obtained were age, gender, tumor mutational burden (TMB), and the distinct genomic alterations noted on DNA sequencing. The dataset was sorted by TP53 mutation status. Differences in mutation frequency were detected using the Fisher’s exact test of independence with a p-value of < 0.01 designated as the cutoff value for statistical significance. Results: The dataset consisted of 2946 GCs and 795 GEAs. TP53 mutations were present in 65.8% of specimens. 61.6% of GCs and 81.4% of GEAs were TP53 MUT positive (p = < .001). Median TMB score and the frequency of tumors with a TMB score > 10 was similar in both TP53 MUT and WT groups. 49 genes had statistically different mutation frequencies in TP53 MUT vs. WT patients. Top co-occurring genetic alterations in TP53 MUT patients included amplification and point mutations in MYC, CCNE1, MET, ERBB2, and EGFR. Amplification and point mutations in MDM2, CDK4, ARID1A, PIK3CA, and ERBB3 were the top co-occurring genetic alterations in TP53 WT patients. Conclusions: There was a high frequency of TP53 mutations in this group of GC and GEA patients, with a higher incidence of TP53 mutations identified in GEA samples. The mutational profiles of these tumors differed according to TP53 mutation status. These differences may be able to serve as the foundation for future clinical investigations.

Pretreatment CT and 18 F-FDG PET-based radiomic model predicting pathological complete response and loco-regional control following neoadjuvant chemoradiation in oesophageal cancer

INTRODUCTION

To develop a radiomic-based model to predict pathological complete response (pCR) and outcome following neoadjuvant chemoradiotherapy (NACRT) in oesophageal cancer.

METHODS

We analysed 68 patients with oesophageal cancer treated with NACRT followed by esophagectomy, who had staging 18F-fluorodeoxyglucose (¹⁸ F-FDG) positron emission tomography (PET) and computed tomography (CT) scans performed at our institution. An in-house data-chjmirocterization algorithm was used to extract 3D-radiomic features from the segmented primary disease. Prediction models were constructed and internally validated. Composite feature, F_c  = α * F_PET  + (1 - α) * F_CT , 0 ≤ α ≤ 1, was constructed for each corresponding CT and PET feature. Loco-regional control (LRC), recurrence-free survival (RFS), metastasis-free survival (MFS) and overall survival (OS) were estimated by Kaplan-Meier analysis, and compared using log-rank test.

RESULTS

Median follow-up was 59 months. pCR was achieved in 34 (50%) patients. Five-year RFS, LRC, MFS and OS were 67.1%, 88.5%, 75.6% and 57.6%, respectively. Tumour Regression Grade (TRG) 0-1 indicative of complete response or minimal residual disease was significantly associated with improved 5-year LRC [93.7% vs 71.8%; P = 0.020; HR 0.19, 95% CI 0.04-0.85]. Four sepjmirote pCR predictive models were built for CT alone, PET alone, CT+PET and composite. CT, PET and CT+PET models had AUC 0.73 ± 0.08, 0.66 ± 0.08 and 0.77 ± 0.07, respectively. The composite model resulted in an improvement of pCR predicting power with AUC 0.87 ± 0.06. Stratifying patients with a low versus high radiomic score showed clinically relevant improvement in 5-year LRC favouring low-score group (91.1% vs. 80%, 95% CI 0.09-1.77, P = 0.2).

CONCLUSION

The composite CT/PET radiomics model was highly predictive of pCR following NACRT. Validation in larger data sets is warranted to determine whether the model can predict clinical outcomes.

Novel MR-Guided Radiotherapy Elective Rotation for Radiation Oncology Trainees

MR-guided adaptive radiation therapy (RT) is emerging as an integral treatment modality for certain applications and is poised to become an exciting opportunity for greater treatment precision and personalization. However, this is still a relatively nascent technology and only a few institutions and programs have access to this technology for clinical use and trainee education. To increase the diversity of elective offerings and improve the understanding of an MR-guided radiotherapy program, we initiated a unique MR-guided radiotherapy elective rotation for radiation oncology residents. During a representative four-week rotation, 21 simulations were completed by the resident on service. A plurality of simulations were for pancreas stereotactic body radiation therapy (SBRT; 48%) and a majority (71%) of simulations were for adaptive treatments. Additionally, 74 adaptive fractions were completed during this month, of which a significant majority (74%) were for pancreas SBRT. Of the non-adaptive fractions, the majority were for prostate SBRT and intensity-modulated radiation therapy (IMRT). Although many programs may offer training in some aspects of MR-guided radiotherapy as trainees rotate through certain disease sites, we hope this may serve as a blueprint to encourage programs with this technology to fully embrace training in essential competencies related to MR-guided radiotherapy. MR-guided radiotherapy has unique challenges that trainees need to understand to deliver treatment safely: geometric uncertainty, MRI to RT isocenter, and uncertainties with voxel size/tracking.

Abstract 4293: Final result of lenvatinib and capecitabine in combination with external beam radiation in treatment of locally advanced rectal cancer: Phase I clinical trial

Purpose: Targeting dual/multiple angiogenesis receptor has been shown to augment tumor response. Lenvatinib, a multikinase inhibitor aimed towards FGFR/ PDGFR/ KIT/RET has shown potent antitumor activity in preclinical models. This study aims to understand the effectiveness and safety of lenvatinib and capecitabine combined with radiation in patients with locally advanced rectal cancer (LARC).

Methods: Patients with MRI or endoscopic ultrasound confirmed stage II or stage III rectal cancer were enrolled in 3 cohorts. All cohorts received standard dose 850 mg/m2 PO BID of capecitabine and external beam radiation (180 cGY) on day 1-5 weekly for 5 ½ to 6 weeks. Oral lenvatinib was administered in dose escalation manner in 3 cohorts of 3 patients per dose level (DL), with an expansion cohort at the MTD [cohort 1:14 mg daily; cohort 2: 20 mg daily; cohort 3:24 mg daily]. At the MTD dose, 10 additional patients were added to further evaluate safety and efficacy.

Results: Twenty patients were enrolled and received at least 1 dose of study drug. One patient was deemed not eligible due to having stage IV disease at the time of diagnosis and is only reviewed for toxicity. 3/19 patients had stage II and 16/19 had stage III cancer at time of enrollment. 73.6% (14/19) patients enrolled were male and 26.4% (5/19) were female. The median age was 55 years (42,73). There was no noted dose limited toxicity at maximum tolerated dose (24 mg) of lenvatinib. There were no grade 4 adverse events. The most common grade 3 toxicities were hypertension observed in 15% (3/20) and lymphopenia in 15% (3/20) patients. Other grade 3 toxicities included rectal pain, hyponatremia, lymphopenia, leukocytosis and transaminitis, each noted in 5% (1/20) patients respectively. 19 patients underwent surgery in 6-10 weeks following completion of dual-targeted therapy and radiation. Median time to surgery was 62 days. There were no peri-operative adverse events. 14/19 patients underwent low anterior resection and 5 have had abdominoperineal resection. 7/19 (36.8%) showed complete pathological response (cPR), and downstaging were seen in 73.7% of the patients (14/19). The mean neoadjuvant rectal cancer score (NAR) was 10.4 and median NAR was 8.43.

Conclusion: The combination of lenvatinib and capecitabine plus radiation shows encouraging safety and efficacy results. Larger randomized study is warranted to verify our findings.

Citation Format: Ankita Tandon, Jessica M. Frakes, Rutika Mehta, Sarah Hoffe, Iman Imanirad, Maria E. Martinez Jimenez, Julian Sanchez, Mokenge Malafa, Seth Felder, Sophie Dessureault, Richard D. Kim. Final result of lenvatinib and capecitabine in combination with external beam radiation in treatment of locally advanced rectal cancer: Phase I clinical trial [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4293.

Modeling precision genomic-based radiation dose response in rectal cancer

Aim: Genomic-based risk stratification to personalize radiation dose in rectal cancer. Patients & methods: We modeled genomic-based radiation dose response using the previously validated radiosensitivity index (RSI) and the clinically actionable genomic-adjusted radiation dose. Results: RSI of rectal cancer ranged from 0.19 to 0.81 in a bimodal distribution. A pathologic complete response rate of 21% was achieved in tumors with an RSI <0.31 at a minimal genomic-adjusted radiation dose of 29.76 when modeling RxRSI to the commonly prescribed physical dose of 50 Gy. RxRSI-based dose escalation to 55 Gy in tumors with an RSI of 0.31-0.34 could increase pathologic complete response by 10%. Conclusion: This study provides a theoretical platform for development of an RxRSI-based prospective trial in rectal cancer.

CT-based radiomic features to predict pathological response in rectal cancer: A retrospective cohort study

INTRODUCTION

Innovative biomarkers to predict treatment response in rectal cancer would be helpful in optimizing personalized treatment approaches. In this study, we aimed to develop and validate a CT-based radiomic imaging biomarker to predict pathological response.

METHODS

We used two independent cohorts of rectal cancer patients to develop and validate a CT-based radiomic imaging biomarker predictive of treatment response. A total of 91 rectal cancer cases treated from 2009 to 2018 were assessed for the tumour regression grade (TRG) (0 = pathological complete response, pCR; 1 = moderate response; 2 = partial response; 3 = poor response). Exploratory analysis was performed by combining pre-treatment non-contrast CT images and patterns of TRG. The models built from the training cohort were further assessed using the independent validation cohort.

RESULTS

The patterns of pathological response in training and validation groups were TRG 0 (n = 14, 23.3%; n = 6, 19.4%), 1 (n = 31, 51.7%; n = 15, 48.4%), 2 (n = 12, 20.0%; n = 7, 22.6%) and 3 (n = 3, 5.0%; n = 3, 9.7%), respectively. Separate predictive models were built and analysed from CT features for pathological response. For pathological response prediction, the model including 8 radiomic features by random forest method resulted in 83.9% accuracy in predicting TRG 0 vs TRG 1-3 in validation.

CONCLUSION

The pre-treatment CT-based radiomic signatures were developed and validated in two independent cohorts. This imaging biomarker provided a promising way to predict pCR and select patients for non-operative management.

Clinical factors associated with the development of postoperative atrial fibrillation in esophageal cancer patients receiving multimodality therapy before surgery

Background

The incidence of esophageal cancer (EC) is increasing in the USA. Neoadjuvant therapy for locally advanced cancers followed by surgical resection is the standard of care. The most common post-esophagectomy cardiac complication is atrial fibrillation (AF). New-onset postoperative AF can require a prolonged hospital stay and may confer an overall poorer prognosis. In this study, we seek to identify clinical factors associated with postoperative AF.

Methods

Query of an IRB approved database of 1,039 esophagectomies at our institution revealed 677 patients with EC from 1999 to 2017 who underwent esophagectomy after neoadjuvant treatment. Age, treatment location (primary vs. other), gender, neoadjuvant radiation type [2D vs. 3D vs. intensity modulated radiation therapy (IMRT)], radiation dose, surgery type (transthoracic vs. transhiatal vs. three field), smoking history, coronary artery disease (CAD), chronic obstructive pulmonary disease (COPD), operative time, blood transfusions, fluid management, and length of stay (LOS) were analyzed in relationship to the development of AF. Statistical analysis was performed with SPSS 24.

Results

The mean age of the entire cohort was 64.3 (range, 28-86 years), with a Caucasian and male preponderance (White: 94.5%; male: 83.6%). Of the 677 patients, 14.9% (n=101) developed postoperative AF. Increasing age (P<0.001), increased radiation dose (P=0.034), operative time (P=0.001), and blood transfusions (P=0.027) were associated with AF. LOS was longer in patients with AF than those without AF (10.5 vs. 10.0 days, P=0.001). On multivariate analysis, increasing age (95% CI: 1.023-1.080, P<0.001) and radiation dose (95% CI: 1.000-1.001, P=0.034) remained significant. None of the other parameters assessed were associated with the development of AF.

Conclusions

Increasing age and radiation dose were associated with the development of postoperative AF in this cohort. This study suggests that older patients or patients receiving higher radiation dose should be monitored more closely in the postoperative setting and potentially referred earlier preoperatively for cardio-oncology assessment. Future study is required to determine if modification of current radiation techniques and cardiac dose constraints in this patient population may be warranted.

Clinical Factors and Outcomes of Octogenarians Receiving Curative Surgery for Esophageal Cancer

BACKGROUND

The incidence of esophageal cancer is increasing in the United States. Although neoadjuvant therapy (NAT) for locally advanced cancers followed by surgical resection is the standard of care, there are no clearly defined guidelines for patients aged ≥79 y.

METHODS

Query of an institutional review board-approved database of 1031 esophagectomies at our institution revealed 35 patients aged ≥79 y from 1999 to 2017 who underwent esophagectomy. Age, gender, tumor location, histology, clinical stage, Charlson Comorbidity Index (CCI), NAT administration, pathologic response rate to NAT, surgery type, negative margin resection status, postoperative complications, postoperative death, length of stay, 30- and 90-d mortality, and disease status parameters were analyzed in association with clinical outcome.

RESULTS

The median age of the octogenarian cohort was 82.1 y with a male preponderance (91.4%). American Joint Committee on Cancer clinical staging was stage I for 20% of patients, stage II for 27% of patients, and stage III for 50% of patients, which was not statistically significant compared with the younger cohort (P = 0.576). Within the octogenarian group, 54% received NAT compared with 67% in the younger group (P = 0.098). There was no difference in postoperative complications (P = 0.424), postoperative death (P = 0.312), and recurrence rate (P = 0.434) between the groups. However, CCI was significantly different between the octogenarian and nonoctogenarian cohort (P = 0.008), and octogenarians had shorter overall survival (18 versus 62 mo, P<0.001). None of the other parameters assessed were associated with clinical outcomes.

CONCLUSIONS

Curative surgery is viable and safe for octogenarians with esophageal cancer. Long-term survival was significantly shorter in the octogenarian group, suggesting the need for better clinical selection criteria for esophagectomy after chemoradiation and that identification of complete responders for nonoperative management is warranted.

Radiation-induced hepatitis masquerading as metastatic disease: the importance of correlating diagnostic imaging with treatment planning

We are presenting a 63-year-old Caucasian male who complained of 2 months of progressive dysphagia. Upper endoscopy discovered a mass in the distal esophagus near the gastroesophageal junction. Biopsy was consistent with adenocarcinoma. Endoscopic ultrasound (EUS) showed extension beyond the muscularis propria, with an enlarged paraesophageal lymph node (T3N1). Initial positron emission tomography (PET)/computed tomography (CT) showed hypermetabolic portocaval lymphadenopathy presumed to be metastatic, but otherwise without distant disease extension. Neoadjuvant treatment included induction FOLFOX followed by 5,600 cGy over 28 fractions in combination with 5-FU and oxaliplatin. Approximately 3.5 weeks after completion, a repeat PET/CT revealed reduced uptake in both the primary esophageal mass and regional lymph nodes. Of note there were several new mass-like foci of hypermetabolism in the liver, specifically the left lobe, concerning for metastatic disease. Image-guided biopsy did not show any identifiable lesions, but sampling was performed based on anatomical landmarks. Pathology revealed benign parenchyma with minimal inflammation and mild reactive regeneration. In light of this, the patient proceeded to undergo definitive resection via robotic Ivor-Lewis esophagectomy with only 1 positive lymph node. Given pleural involvement by the tumor, staging was revised to pT4aN1 with final histology characterized as adenosquamous carcinoma. Postoperative course was fairly uneventful, with a mild exacerbation of his chronic heart failure. The patient was discharged on post-operative day 7, with his feeding tube removed at his 2-week post-operative clinic visit. This scenario is of particular educational value from the standpoint that when the post-treatment PET/CT images are registered to the radiotherapy treatment planning CT and dose, the areas of abnormal uptake in the liver fall within the higher dose regions. Given this and the liver biopsy findings, caution should be exercised before declaring progressive disease following radiotherapy without first reviewing the treatment plan.

Neoadjuvant FOLFIRINOX in Patients With Borderline Resectable Pancreatic Cancer: A Systematic Review and Patient-Level Meta-Analysis

BACKGROUND

FOLFIRINOX is a standard treatment for metastatic pancreatic cancer patients. The effectiveness of neoadjuvant FOLFIRINOX in patients with borderline resectable pancreatic cancer (BRPC) remains debated.

METHODS

We performed a systematic review and patient-level meta-analysis on neoadjuvant FOLFIRINOX in patients with BRPC. Studies with BRPC patients who received FOLFIRINOX as first-line neoadjuvant treatment were included. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival, resection rate, R0 resection rate, and grade III-IV adverse events. Patient-level survival outcomes were obtained from authors of the included studies and analyzed using the Kaplan-Meier method.

RESULTS

We included 24 studies (8 prospective, 16 retrospective), comprising 313 (38.1%) BRPC patients treated with FOLFIRINOX. Most studies (n = 20) presented intention-to-treat results. The median number of administered neoadjuvant FOLFIRINOX cycles ranged from 4 to 9. The resection rate was 67.8% (95% confidence interval [CI] = 60.1% to 74.6%), and the R0-resection rate was 83.9% (95% CI = 76.8% to 89.1%). The median OS varied from 11.0 to 34.2 months across studies. Patient-level survival data were obtained for 20 studies representing 283 BRPC patients. The patient-level median OS was 22.2 months (95% CI = 18.8 to 25.6 months), and patient-level median progression-free survival was 18.0 months (95% CI = 14.5 to 21.5 months). Pooled event rates for grade III-IV adverse events were highest for neutropenia (17.5 per 100 patients, 95% CI = 10.3% to 28.3%), diarrhea (11.1 per 100 patients, 95% CI = 8.6 to 14.3), and fatigue (10.8 per 100 patients, 95% CI = 8.1 to 14.2). No deaths were attributed to FOLFIRINOX.

CONCLUSIONS

This patient-level meta-analysis of BRPC patients treated with neoadjuvant FOLFIRINOX showed a favorable median OS, resection rate, and R0-resection rate. These results need to be assessed in a randomized trial.

Intensity-modulated radiotherapy at high-volume centers improves survival in patients with esophageal adenocarcinoma receiving trimodality therapy

The standard of care trimodality therapy for resectable locally advanced esophageal adenocarcinoma is complex and necessitates multidisciplinary care and expertise. In this work, it is hypothesized that facility clinical volume and utilization of intensity-modulated radiotherapy (IMRT) may influence outcomes. The National Cancer Data Base was queried for patients with cT1-4-N0-3 M0 esophageal adenocarcinoma undergoing trimodality therapy from 2004 to 2013 (n = 2445). All patients received chemoradiation followed by esophagectomy at a Commission on Cancer facility. The facility volume was categorized into tertiles: high-volume centers (HVCs) in the highest 25th percentile of cases per year, intermediate-volume centers (IVCs) with the next highest 25th percentile of cases, and low- and very low-volume centers (LVCs) in the lowest 50th percentile. Overall survival (OS) was estimated using Kaplan-Meier methods and Cox proportional hazard regression. Propensity score matching to balance patient characteristics between volume centers was performed. Subgroup analysis was done comparing IMRT versus 3D conformal radiotherapy. The median follow-up was 26 months. Treatment at an HVC (hazard ratio 0.63, 95% CI 0.49-0.81, P < 0.001) was found to be independently associated with improved overall survival in multivariable analysis. Three-year OS was 58.4%, 46.2%, and 47.5% for HVCs, IVCs, and LVCs, respectively (P < 0.001). Patients at HVCs were more likely to receive IMRT over 3D chemoradiation (CRT; OR 3.45, 95% CI 2.4-5.0, P < 0.001). Patients treated using IMRT at HVCs had improved OS compared to those treated at IVCs or LVCs (HR 0.68, 95% CI 0.52-0.90, P < 0.01), while patients treated with 3D CRT at HVCs had no survival advantage over those at IVCs or LVCs (P = 0.28). Patients with locally advanced esophageal adenocarcinoma treated with IMRT and at HVCs appear to have improved survival.

The impact of location on the prognosis of squamous cell carcinomas of the anorectal region

BACKGROUND

Because anal and rectal squamous cell carcinomas (R-SCCs and A-SCCs) share a common histology and an excellent response to chemoradiation, we hypothesized that R-SCC and A-SCC may represent a similar biological entity, and location would not affect clinical presentation and prognosis.

METHODS

Patients diagnosed with R-SCC (n = 2881) and A-SCC (n = 21,854) were identified in the Surveillance, Epidemiology, and End Results database (1998-2013). R-SCCs were staged based on American Joint Committee on Cancer classification for A-SCC, and impact of location was analyzed accordingly.

RESULTS

Compared to A-SCC, R-SCCs were more common in females (65% versus 48%, P < 0.001) and older patients (62 versus 56 yrs, P < 0.001). R-SCC presented with more advanced disease than A-SCC: mean size 4.2 versus 3.6 cm; T4 14% versus 5%; nodal involvement 20% versus 15%; and metastases 13% versus 6% (all P < 0.001). In multivariable analysis, R-SCCs and A-SCCs had similar disease-specific survival (DSS) for stages 0, I, and III; however, stage II R-SCC had significantly worse DSS than A-SCCs (P = 0.002). This was due to a greater proportion of T3 (>5 cm) R-SCC tumors (36% versus 27%, P < 0.001), which had a lower DSS than T2 (2-5 cm) tumors. Within T3 and T4 tumors, R-SCCs had lower DSS than A-SCCs.

CONCLUSIONS

R-SCC presented with higher stages than A-SCC, suggesting a delayed diagnosis. Larger R-SCC (T3-T4) had worse survival compared to T3-4 A-SCC, which may be due to a combination of more advanced disease within-stage as well as the use of less efficacious therapeutic regimens. Therefore, location may represent a significant prognostic factor for SCC of the anorectal region.

Patient choice for high-volume center radiation impacts head and neck cancer outcome

Background

Studies suggest treatment outcomes may vary between high (HVC)‐ and low‐volume centers (LVC). Radiation therapy (RT) for head and neck cancer (HNC) requires weeks of treatment, the inconvenience of which may influence a patient's choice for treatment location. We hypothesized that receipt of RT for HNC at a HVC would influence outcomes compared to patients evaluated at a HVC, but who chose to receive RT at a LVC.

Methods

From 1998 to 2011, 1930 HNC patients were evaluated at a HVC and then treated with RT at either a HVC or LVC. Time‐to‐event outcomes and treatment factors were compared.

Results

Median follow‐up was 34 months. RT was delivered at a HVC for 1368 (71%) patients and at a LVC in 562 (29%). Patients were more likely to choose HVC‐RT if they resided in the HVC's county or required definitive RT (all P < 0.001). HVC‐RT was associated with a significant improvement in 3‐year LRC (84% vs 68%), DFS (68% vs 48%), and OS (72% vs 57%) (all P < 0.001). On multivariate analysis (MVA), HVC‐RT independently predicted for improved LRC, DFS, and OS (all P < 0.05).

Conclusions

In patients evaluated at a HVC, the choice of RT location was primarily influenced by their residing distance from the HVC. HVC‐RT was associated with improvements in LRC, DFS, and OS in HNC. As treatment planning and delivery are technically demanding in HNC, the choice to undergo treatment at a HVC may result in more optimal delivered dose, RT duration, and outcome.

Intrahepatic Cholangiocarcinoma Treated with Transarterial Yttrium-90 Glass Microsphere Radioembolization: Results of a Single Institution Retrospective Study

PURPOSE

To evaluate the efficacy and safety of transarterial yttrium-90 glass microsphere radioembolization in patients with unresectable intrahepatic cholangiocarcinoma (ICC).

MATERIALS AND METHODS

Retrospective review of 85 consecutive patients (41 men and 44 women; age, 73.4 ± 9.3 years) was performed. Survival data were analyzed by the Kaplan-Meier method, Cox regression models, and the log-rank test.

RESULTS

Median overall survival (OS) from diagnosis was 21.4 months (95% confidence interval [CI]: 16.6-28.4); median OS from radioembolization was 12.0 months (95% CI: 8.0-15.2). Seven episodes of severe toxicity occurred. At 3 months, 6.2% of patients had partial response, 64.2% had stable disease, and 29.6% had progressive disease. Median OS from radioembolization was significantly longer in patients with Eastern Cooperative Oncology Group (ECOG) scores of 0 and 1 than patients with an ECOG score of 2 (18.5 vs 5.5 months, P = .0012), and median OS from radioembolization was significantly longer in patients with well-differentiated histology than patients with poorly differentiated histology (18.6 vs 9.7 months, P = .012). Patients with solitary tumors had significantly longer median OS from radioembolization than patients with multifocal disease (25 vs. 6.1 months, P = .006). The absence of extrahepatic metastasis was associated with significantly increased median OS (15.2 vs. 6.8 months, P = .003). Increased time from diagnosis to radioembolization was a negative predictor of OS. The morphology of the tumor (mass-forming or infiltrative, hyper- or hypo-enhancing) had no effect on survival. Post-treatment increased cancer antigen 19-9 level, increased international normalized ratio, decreased albumin, increased bilirubin, increased aspartate aminotransferase, and increased Model for End-Stage Liver Disease score were significant predictors of decreased OS.

CONCLUSIONS

These data support the therapeutic role of radioembolization for the treatment of unresectable ICC with good efficacy and an acceptable safety profile.

Viral hepatitis associated hepatocellular carcinoma outcomes with yttrium-90 radioembolization

Background

Viral associated (VA) malignancies have recently been correlated with improved outcomes. We sought to evaluate outcomes of patients with hepatocellular carcinoma (HCC) with and without viral hepatitis (hepatitis B and C) treated with lobar yttrium-90 radioembolization (Y-90 RE).

Methods

After IRB approval, an institutional database of patients with HCC who received RE between 2009-2014 was queried and 99 patients were identified that received a total of 122 lobar RE. Charts were reviewed to capture previous treatments, viral hepatitis status, α-fetoprotein values (AFP), Child-Pugh class (CP), albumin-bilirubin score (ALBI), portal vein thrombosis (PVT), volumes treated and doses delivered. Comparison was made with Chi-square and Mann-Whitney U test. Intrahepatic control (IHC), extrahepatic control (EHC), progression free survival (PFS), and overall survival (OS) were calculated according to the Kaplan-Meier method stratified by cause of underlying liver disease (viral vs. non-viral) and survival differences were assessed via the log-rank test. Hazard ratios were calculated using Cox regression.

Results

Median follow up for VA HCC and non-VA (NVA) HCC patients was 10.9 months (range, 0.8-46.7 months) and 11.8 months (range, 1.1-62.8 months), respectively. Patients with VA HCC (n=44) were younger (P<0.001) and had smaller pretreatment liver volumes (P<0.001); however, there was no difference with respect to gender, pre-treatment AFP, CP, ALBI, PVT, extrahepatic disease, previous treatment, or dose delivered. Median doses for VA and NVA HCC patients were 129.5 Gy (range, 90-215.8 Gy) and 131 Gy (range, 100.9-265 Gy), respectively (P=0.75). One year IHC showed a strong trend to better control for VA HCC at 67% versus 34% for NVA HCC (P=0.067) but 1 year EHC was significantly worse at 63% for VA HCC versus 86% for NVA HCC (P=0.027). There were no significant differences in survival, with a 1-year PFS of 45% for VA HCC versus 31% for NVA HCC (P=0.56) and 1 year OS of 46% versus 55% (P=0.55). Patients that received salvage treatments, CP A, no PVT, and those without extrahepatic disease had improved OS.

Conclusions

Patients with VA HCC had a trend to improved IHC and significantly worse EHC. Prospective investigation of novel systemic therapies following Y-90 RE in patients with VA HCC is warranted to potentially further extend survival in VA HCC patients by addressing extra-hepatic disease.

Adjuvant radiation provides survival benefit for resected pancreatic adenocarcinomas of the tail

BACKGROUND

The appropriate adjuvant treatment for resected pancreatic cancer remains a controversy. We sought to determine the effect of adjuvant treatment on overall survival (OS) in patients with pancreatic tail adenocarcinoma.

METHODS

Retrospective review of patients with upfront surgically resected pancreatic tail cancer treated at our institution between 2000-2012 was performed to determine outcomes of patients treated with and without adjuvant radiation therapy (RT). Survival curves were calculated according to the Kaplan-Meier method. Univariate analysis (UVA) and multivariate analysis (MVA) were performed using the Cox proportional hazards model.

RESULTS

Thirty-four patients met inclusion criteria. 79% received adjuvant chemotherapy, either concurrent with RT or alone. The groups were well matched, with the only significant difference being patient sex. On both UVA and MVA there was significantly worse survival in patients with a post-op CA19-9 >90 [hazard ratio (HR) 5.55; 95% confidence interval (CI): 1.20-25.7, P=0.03] and improved survival in patients treated with adjuvant RT (HR 0.15; 95% CI: 0.04-0.58, P=0.006). The median and 2-year OS were 21.6 months and 47% for patients treated with adjuvant RT compared with 11.3 months and 21% for those treated without RT.

CONCLUSIONS

Although few in patient numbers, this data suggests integration of adjuvant RT in resected pancreatic tail adenocarcinoma may improve OS.

Association of radiomics and outcome in esophageal cancer following neoadjuvant chemo-radiation

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Background: Radiomic data extraction from medical images has the potential to differentiate tumor phenotypes. We investigated the potential of esophageal cancer radiomic features to differentiate clinical outcomes following neoadjuvant chemoradiation (NACRT). Methods: We retrospectively reviewed 68 biopsy-proven mid-distal esophageal/gastroesophageal junction (GEJ) cancer patients treated from 2007-2014 with NACRT followed by esophagectomy on an IRB approved study in which patients were eligible if imaging was performed at our institution. The primary tumor was segmented on baseline computed tomography (CT) and 18-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) scans with contour review by two independent radiation oncologists. A total of 126 quantitative 3-D shape and intensity-based radiomics features were extracted using in-house data algorithm software. Locoregional control (LRC), metastasis free survival (DFS), metastasis free survival (MFS) and overall survival (OS) were estimated by Kaplan-Meier analysis and multivariate Cox proportion hazard. Results: Estimated actuarial 5-year RFS, LRC, MFS, OS was 56.6% (mean: 67.8 months, 95% CI 53.7-81.8 months), 83.1% (mean: 92.8 months, 95% CI 81.4-104.2 months), 64.9% (mean: 76.4 months, 95% CI 62.2-90.7 months), 39.5% (median survival 40 months, 95% CI 24.59-55.40), respectively. Pathological complete response (pCR) was achieved in 34 (50%) patients. Tumor Regression Grade (TRG) 0-1 indicative of complete response was associated with improved LRC [p = 0.04; Hazard Ratio (HR) 4.24 (1.01-19.01)]. On univariate analysis, 16 PET-based and 14 CT-based radiomics features were found to independently predict pCR. On multivariate analysis (MVA), three PET-CT based radiomic features [sphericity (p = 0.04), compactness (p = .05) and PET_TGV (p = 0.08)] were found to closely predict pCR. When grouped by median, PET sphericity independently predicted RFS [p = 0.014; Hazard Ratio (HR) 0.31 95% Confidence Interval (CI) 0.11-0.83]. Conclusions: This study suggests pre-treatment radiomic features in esophageal cancer may be prognostic for response assessment (pCR) and overall outcome following NACRT.

Development of a radiomic signature for prediction of pathological complete response following neoadjuvant chemoradiotherapy in esophageal cancer

106

Background: Pivotal to personalized therapy is accurate pre-treatment patient selection based on predictive biomarkers. We developed a radiomic signature model to predict pathological complete response (pCR) following neoadjuvant chemo-radiotherapy (NACRT) in esophageal cancers. Methods: We retrospectively identified 68 patients with esophageal cancer, treated with NACRT followed by esophagectomy, with baseline 18F-fluorodeoxyglucose Positron Emission Tomography (PET) and computed tomography (CT) scans performed at our institution. In-house data-characterization algorithm was used to extract 3D radiomics features from the segmented primary disease. Prediction models were constructed and internally validated (2/3rd training, 1/3rd validation) using machine learning software. Cox regression hazard used to assess association with relapse free survival (RFS). Results: pCR was observed in 34 (50%) patients. A total of 126 features were extracted individually from PET and CT scans. On univariate analysis, 16 PET and 14 CT features were found to independently predict pCR. Three separate predictive models were built for CT, PET and combined CT+PET. Individually, both CT and PET had a good predictive power with AUC 0.74 and 0.730, respectively. Combined CT+PET radiomic features resulted in a significant improvement of predicting power, with AUC 0.856. Good discrimination (82.6%) was observed in validation dataset. Final model was: 13.439-34.632(CT-eccentricity)-2.469(CT-LRLGE)+10.626(CT-Gnorm_HIE)-2.094(CT-SD_Lac2)-19.337(CT-FD_SD)-0.344(PET-Contrast), where eccentricity is shape feature, LRLGE a gray level run length feature, Gnorm_HIE gray-level size zone feature, SD_Lac2 a fractal dimension feature. Stratifying patients with low vs. high radiomic signature score predicted RFS: median RFS 80.1 vs. 40.1 months; and 2-year RFS 77.4% vs. 52.6% [Hazard Ratio: 2.24, 95% CI 1.01-5.58], respectively. Conclusions: The developed radiomics signature models were highly predictive of pCR following NACRT. Further validation in larger data sets is needed to determine whether the model can predict clinical outcomes.

Impact of sarcopenia in borderline resectable and locally advanced pancreatic cancer patients receiving stereotactic body radiation therapy

Background

Total psoas area (TPA), a marker of sarcopenia, has been used as an independent predictor of clinical outcomes in gastrointestinal (GI) cancers as a proxy for frailty and nutritional status. Our study aimed to evaluate whether TPA, in contrast to traditional measurements of nutrition like body mass index (BMI) and body surface area (BSA), was predictive of outcomes in borderline resectable pancreatic cancer (BRPC) and locally advanced pancreatic cancer (LAPC) patients receiving stereotactic body radiation therapy (SBRT).

Methods

Retrospective analysis of an institutional review board approved database of 222 BRPC and LAPC treated with SBRT from 2009-2016 yielded 183 patients that met our selection criteria of pre-SBRT computed tomography (CT) imaging with an identifiable L4 vertebra. Once the L4 vertebral level was identified, the bilateral psoas muscles were manually contoured. This area was normalized by patient height, with units described in mm²/m². Receiver operating characteristic (ROC) curves were generated for TPA, BMI, and BSA to elicit clinically relevant cutoffs. Regression and Kaplan-Meier analyses were used to correlate toxicity with survival functions.

Results

Low TPA (OR =1.903, P=0.036) was predictive of acute toxicities, and only TPA was predictive of Grade 3 or higher acute toxicities (OR =10.24, P=0.007). Both findings were independent of tumor resectability. Pain (P=0.003), fatigue (P=0.040), and nausea (P=0.039) were significantly associated with low TPA. No association was identified between any measurement of nutritional status and the development of late toxicities, overall survival, local progression or local recurrence. However, BRPC patients survived longer (median =21.98 months) than their LAPC (median =16.2 months) counterparts (P=0.002), independent of nutritional status.

Conclusions

TPA measurement is readily available and more specific than BMI or BSA as a predictor of acute radiotoxic complications following SBRT in BRPC/LAPC patients. A TPA of <500 mm²/m² is a clinically relevant cutoff that can direct physicians to address expected complications of pain, fatigue, and nausea. However, tumor resectability remains as the only predictor of overall survival in this cohort.

Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

The role of external beam radiation therapy for primary liver malignancies has historically been limited due to the risk of radiation-induced liver disease. However, with the advent of stereotactic body radiotherapy (SBRT), we are able to dose escalate while safely sparing critical nearby structures. This review explores the evidence surrounding the use of SBRT for the treatment of primary liver malignancies. A review of the literature was performed. This article discusses the challenges, efficacy, and safety of SBRT for primary liver malignancies in order to conceptualize its role within a multidisciplinary framework. Prospective phase I and II trials show local control rates at 1 to 2 years ranging from 65% to 100%. Overall survival at 1 to 2 years ranged from 48% to 77%. Grade >3 toxicity ranged from 0% to 36%. Total radiotherapy doses ranged from 24 to 60 Gy delivered in 1 to 6 fractions. The SBRT offers a noninvasive therapy for patients with limited treatment options and should be considered in a multidisciplinary setting for the management of unresectable, locally advanced primary liver malignancies. Prospective randomized trials are warranted to determine the efficacy and safety of SBRT compared to and in combination with other treatment modalities.