Stereotactic body radiation vs. intensity-modulated radiation for unresectable pancreatic cancer

Prediction of Isolated Local Recurrence After Resection of Pancreatic Ductal Adenocarcinoma: A Nationwide Study

BACKGROUND

Distinguishing postoperative fibrosis from isolated local recurrence (ILR) after resection of pancreatic ductal adenocarcinoma (PDAC) is challenging. A prognostic model that helps to identify patients at risk of ILR can assist clinicians when evaluating patients' postoperative imaging. This nationwide study aimed to develop a clinically applicable prognostic model for ILR after PDAC resection.

PATIENTS AND METHODS

An observational cohort study was performed, including all patients who underwent PDAC resection in the Netherlands (2014-2019; NCT04605237). On the basis of recurrence location (ILR, systemic, or both), multivariable cause-specific Cox-proportional hazard analysis was conducted to identify predictors for ILR and presented as hazard ratios (HRs) with 95% confidence intervals (CIs). A predictive model was developed using Akaike's Information Criterion, and bootstrapped discrimination and calibration indices were assessed.

RESULTS

Among 1194/1693 patients (71%) with recurrence, 252 patients (21%) developed ILR. Independent predictors for ILR were resectability status (borderline versus resectable, HR 1.42; 95% CI 1.03-1.96; P = 0.03, and locally advanced versus resectable, HR 1.11; 95% CI 0.68-1.82; P = 0.66), tumor location (head versus body/tail, HR 1.50; 95% CI 1.00-2.25; P = 0.05), vascular resection (HR 1.86; 95% CI 1.41-2.45; P < 0.001), perineural invasion (HR 1.47; 95% CI 1.01-2.13; P = 0.02), number of positive lymph nodes (HR 1.04; 95% CI 1.01-1.08; P = 0.02), and resection margin status (R1 < 1 mm versus R0 ≥ 1 mm, HR 1.64; 95% CI 1.25-2.14; P < 0.001). Moderate performance (concordance index 0.66) with adequate calibration (slope 0.99) was achieved.

CONCLUSIONS

This nationwide study identified factors predictive of ILR after PDAC resection. Our prognostic model, available through www.pancreascalculator.com , can be utilized to identify patients with a higher a priori risk of developing ILR, providing important information in patient evaluation and prognostication.

Stereotactic body radiotherapy for pancreatic cancer - A systematic review of prospective data

Purpose

This systematic review aims to comprehensively summarize the current prospective evidence regarding Stereotactic Body Radiotherapy (SBRT) in various clinical contexts for pancreatic cancer including its use as neoadjuvant therapy for borderline resectable pancreatic cancer (BRPC), induction therapy for locally advanced pancreatic cancer (LAPC), salvage therapy for isolated local recurrence (ILR), adjuvant therapy after radical resection, and as a palliative treatment. Special attention is given to the application of magnetic resonance-guided radiotherapy (MRgRT).

Methods

Following PRISMA guidelines, a systematic review of the Medline database via PubMed was conducted focusing on prospective studies published within the past decade. Data were extracted concerning study characteristics, outcome measures, toxicity profiles, SBRT dosage and fractionation regimens, as well as additional systemic therapies.

Results and conclusion

31 studies with in total 1,571 patients were included in this review encompassing 14 studies for LAPC, 9 for neoadjuvant treatment, 2 for adjuvant treatment, 2 for ILR, with an additional 4 studies evaluating MRgRT. In LAPC, SBRT demonstrates encouraging results, characterized by favorable local control rates. Several studies even report conversion to resectable disease with substantial resection rates reaching 39%. The adoption of MRgRT may provide a solution to the challenge to deliver ablative doses while minimizing severe toxicities. In BRPC, select prospective studies combining preoperative ablative-dose SBRT with modern induction systemic therapies have achieved remarkable resection rates of up to 80%. MRgRT also holds potential in this context. Adjuvant SBRT does not appear to confer relevant advantages over chemotherapy. While prospective data for SBRT in ILR and for palliative pain relief are limited, they corroborate positive findings from retrospective studies.

Involved-Field Radiation Therapy for Patients With Unresectable Pancreatic Adenocarcinomas: Failure Pattern Analysis

Introduction Unresectable pancreatic tumors are frequently diagnosed. Initial treatment is carried out with chemotherapy. Eventually, in selected cases, radiotherapy may be used to improve local control rates and relieve the symptoms. The volume of radiotherapy treatment fields is the subject of controversy in the literature. The use of involved fields with the gross tumor volume encompassing the primary tumor and lymph nodes considered clinically positive is associated with a lower rate of side effects, but can lead to a higher rate of regional loco failures, especially in regional lymph nodes. The purpose of this article is to analyze the failure pattern of chemotherapy and involved-field radiation therapy (IFRT) for treating patients with unresectable pancreatic adenocarcinomas. Methods Clinical records of thirty consecutive patients treated from March 2016 to June 2020 for unresectable pancreatic adenocarcinoma were analyzed. The patients were treated with initial systemic chemotherapy (median: 6 cycles) with regimens based on gemcitabine or oxaliplatin-irinotecan (folfirinox/folfox) followed by radiotherapy (total dose of 50-54 Gy/with fractionation of 2 Gy/day). The patients were treated with IFRT. Local failure (LF) was defined as an increase in radiographic abnormality within the planning target volume (PTV). Elective nodal failure (ENF) was defined as recurrence in any lymph node region outside the PTV. Any other failure was defined as distant failure (DF). Results The median age of the patients was 68 years (range: 44-80 years); 20 patients (66.7%) were men, and 11 (36.6%) and 19 (63.4%) patients presented with tumors of stage II and III, respectively. Most patients (63.3%) had tumors in the pancreatic head. The median survival was 17.2 months. Tumor recurrences were classified as LF, DF, LF and DF in 7 (23.3%), 17 (56.7%), and 5 (16.7%) patients, respectively. Only one patient (3.3%) had both LF and ENF. No severe side effects related to radiotherapy were reported. Conclusion The use of IFRT did not cause a significant amount of ENF, besides presenting low morbidity, which is of special importance for patients with locally advanced tumors or low performance status. The predominant failure pattern was distant metastases.

Comparative Effectiveness of Chemotherapy Alone Versus Radiotherapy-Based Regimens in Locally Advanced Pancreatic Cancer: A Real-World Multicenter Analysis (PAULA-1)

Different options for locally advanced pancreatic cancer (LAPC) are available based on international guidelines: chemotherapy (CHT), chemoradiation (CRT), and stereotactic body radiotherapy (SBRT). However, the role of radiotherapy is debated in LAPC. We retrospectively compared CHT, CRT, and SBRT ± CHT in a real-world setting in terms of overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS). LAPC patients from a multicentric retrospective database were included (2005-2018). Survival curves were calculated using the Kaplan-Meier method. Multivariable Cox analysis was performed to identify predictors of LC, OS, and DMFS. Of the 419 patients included, 71.1% were treated with CRT, 15.5% with CHT, and 13.4% with SBRT. Multivariable analysis showed higher LC rates for CRT (HR: 0.56, _95%CI 0.34-0.92, p = 0.022) or SBRT (HR: 0.27, _95%CI 0.13-0.54, p < 0.001), compared to CHT. CRT (HR: 0.44, _95%CI 0.28-0.70, p < 0.001) and SBRT (HR: 0.40, _95%CI 0.22-0.74, p = 0.003) were predictors of prolonged OS with respect to CHT. No significant differences were recorded in terms of DMFS. In selected patients, the addition of radiotherapy to CHT is still an option to be considered. In patients referred for radiotherapy, CRT can be replaced by SBRT considering its duration, higher LC rate, and OS rate, which are at least comparable to that of CRT.

Ablative vs. Non-Ablative Radiotherapy in Palliating Locally Advanced Pancreatic Cancer: A Single Institution Experience and a Systematic Review of the Literature

We studied the dose-local control (LC) relationship in ablative vs. non-ablative radiotherapy in a non-radical treatment setting of "locally advanced pancreatic cancer (LAPC)" by comparing our patients (n = 89) treated with SBRT on the CyberKnife unit vs. conventional radiation between January 2005 and January 2021, and by reviewing the literature. A systematic search was performed leveraging Medline for references on SBRT use in pancreatic cancer without date terms or language restrictions. A total of 3702 references were identified and the search was then repeated in Embase and the Cochrane database. Ultimately, 12 studies were eligible for inclusion, which either compared SBRT to conventional radiation, or SBRT use in dose escalation for primary LAPC in a non-neoadjuvant setting. Our cohort's median overall survival was 152 days (CI 95%, 118-185); including 371 days (CI 95%, 230-511) vs. 126 days (CI 95%, 90-161) favoring SBRT, p = 0.004. The median time to local progression was 170 days (48-923) for SBRT vs. 107 days (27-489) for the non-ablative group. In our SBRT patients, no local progressions were seen with BED₁₀ > 60 Gy. Even when palliating LAPC, SBRT should be considered as an alternative to conventional radiation, especially in patients with a low disease burden. BED₁₀ ≥ 60-70 Gy offers better local control without increasing toxicity rates. Less local progression may provide a better quality of life to those patients who already have a short life expectancy.

Impact of chemoradiotherapy on the survival of unresectable locally advanced pancreatic cancer: a retrospective cohort analysis

BACKGROUND

The role of chemoradiotherapy in unresectable locally advanced pancreatic cancer is still unclear.

METHODS

Data from patients with unresectable locally advanced pancreatic cancer were extracted from the Surveillance, Epidemiology, and End Results Program database. Univariate and multivariate Cox regression analyses were conducted to identify the independent prognostic factors of survival. Propensity score matching was carried out to minimize the interference of confounding factors. Subgroup analysis was performed to screen the characteristics of patients who would benefit from chemoradiotherapy.

RESULTS

A total of 5002 patients with unresectable locally advanced pancreatic cancer were included. Among them, 2423 (48.4%) received chemotherapy, and 2579 (51.6%) received chemoradiotherapy. The median overall survival of all patients was 11 months. Multivariate Cox analysis showed that age (p < 0.001), marital status (p < 0.001), tumor size (p = 0.001), N stage (p = 0.015) and radiotherapy (p < 0.001) were independent prognostic factors of survival. Both before (HR, 0.817; 95% CI, 0.769-0.868; p < 0.001) and after (HR, 0.904; 95% CI, 0.876-0.933; p < 0.001) propensity score matching, chemoradiotherapy significantly improved the median overall survival of patients from 10 to 12 months. Subgroup analysis showed that chemoradiotherapy was significantly associated with improved survival regardless of sex, primary site or N stage. In addition, the following subgroups all significantly benefited from chemoradiotherapy: age ≥ 50 years, not divorced, grade 2-4, tumor size > 2 cm, adenocarcinoma, mucinous adenocarcinoma and white race.

CONCLUSIONS

Chemoradiotherapy is highly recommended for patients with unresectable locally advanced pancreatic cancer.

The Current Role of Radiation in Pancreatic Cancer and Future Directions

Survival outcomes for localized pancreatic adenocarcinoma remains poor. Multimodality therapeutic regimens are critical to maximizing survival outcomes for these patients, which includes the use of systemic therapy, surgery, and radiation. In this review, the evolution of radiation techniques are discussed with a focus on modern techniques such as intensity modulated radiation and stereotactic body radiation therapy. However, the current role of radiation within the most common clinical scenarios for pancreatic cancer in the neoadjuvant, definitive, and adjuvant settings continues to be highly debated. The role of radiation in these settings is reviewed in the context of historical and modern clinical studies. In addition, emerging concepts including dose-escalated radiation, magnetic resonance-guided radiation therapy, and particle therapy are discussed to promote an understanding of how such concepts may change the role of radiation in the future.

Advances in Radiation Oncology for Pancreatic Cancer: An Updated Review

This review aims to summarize the recent advances in radiation oncology for pancreatic cancer. A systematic search of the MEDLINE/PubMed database and Clinicaltrials.gov was performed, focusing on studies published within the last 10 years. Our search queried "locally advanced pancreatic cancer [AND] stereotactic body radiation therapy (SBRT) [OR] hypofractionation [OR] magnetic resonance guidance radiation therapy (MRgRT) [OR] proton" and "borderline resectable pancreatic cancer [AND] neoadjuvant radiation" and was limited only to prospective and retrospective studies and metanalyses. For locally advanced pancreatic cancers (LAPC), retrospective evidence supports the notion of radiation dose escalation to improve overall survival (OS). Novel methods for increasing the dose to high risk areas while avoiding dose to organs at risk (OARs) include SBRT or ablative hypofractionation using a simultaneous integrated boost (SIB) technique, MRgRT, or charged particle therapy. The use of molecularly targeted agents with radiation to improve radiosensitization has also shown promise in several prospective studies. For resectable and borderline resectable pancreatic cancers (RPC and BRPC), several randomized trials are currently underway to study whether current neoadjuvant regimens using radiation may be improved with the use of the multi-drug regimen FOLFIRINOX or immune checkpoint inhibitors.

Multiagent Chemotherapy and Stereotactic Body Radiation Therapy in Patients with Unresectable Pancreatic Adenocarcinoma: A Prospective Nonrandomized Controlled Trial

PURPOSE

In a prospective multicenter study, gemcitabine monotherapy followed by stereotactic body radiation therapy (SBRT) was well tolerated with outcomes comparable to chemoradiation for locally advanced pancreatic cancer (LAPC). Recent trials have reported improved survival with multiagent chemotherapy (MA-CTX) alone. This prospective trial explored whether SBRT could be safely delivered after MA-CTX. Herein, we report the long-term outcomes of adding SBRT after MA-CTX in LAPC patients and evaluate whether genetic profiles of specimens obtained before SBRT influence outcomes.

METHODS AND MATERIALS

This prospective nonrandomized controlled phase 2 trial enrolled 44 LAPC and 4 locally recurrent patients after multidisciplinary evaluation between 2012 and 2015 at a high-volume pancreatic cancer center. For induction CTX, most received modified FOLFIRINOX (mFFX), or gemcitabine and nab-paclitaxel (GnP) followed by 5-fraction SBRT for all. During fiducial placement, biopsies were obtained with DNA extracted for targeted sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets platform.

RESULTS

Median induction CTX duration was ≥4 months, and 31 patients received mFFX (65%). Among 44 LAPC patients, 17 (39%) were surgically explored, and 12 of 16 (75%) achieved a R0 resection. Median overall survival (mOS) was 20.2 and 14.6 months from diagnosis and SBRT, respectively. One- and 2-year OS from SBRT was 58% and 28%. The mOS after resection was 28.6 and 22.4 months from diagnosis and SBRT, respectively. Median local progression-free survival was 23.9 and 15.8 months from diagnosis and SBRT, respectively. The mOS for pre-SBRT CA 19-9 ≤180 U/mL versus >180 was 23.1 and 11.3 months, respectively (hazard ratio, 0.53; P = .04). Only 1 patient (2.1%) had late grade ≥2 gastrointestinal toxic effects attributable to SBRT. Despite significant pretreatment with chemotherapy, 88% of tumor specimens were effectively sequenced; survival outcomes were not significantly associated with specific mutational patterns. Quality of life was prospectively collected pre- and post-SBRT with the EORTC QLQ-C30 and PAN26 questionnaires showing no significant change.

CONCLUSIONS

SBRT was safely administered with MA-CTX with minimal toxicity. A high proportion of LAPC patients underwent R0 resection with favorable survival outcomes.

A nationwide randomized controlled trial on additional treatment for isolated local pancreatic cancer recurrence using stereotactic body radiation therapy (ARCADE)

BACKGROUND

Disease recurrence is the main cause of mortality after resection of pancreatic ductal adenocarcinoma (PDAC). In 20-30% of resected patients, isolated local PDAC recurrence occurs. Retrospective studies have suggested that stereotactic body radiation therapy (SBRT) might lead to improved local control in these patients, potentially having a beneficial effect on both survival and quality of life. The "nationwide randomized controlled trial on additional treatment for isolated local pancreatic cancer recurrence using stereotactic body radiation therapy" (ARCADE) will investigate the value of SBRT in addition to standard of care in patients with isolated local PDAC recurrence compared to standard of care alone, regarding both survival and quality of life outcomes.

METHODS

The ARCADE trial is nested within a prospective cohort (Dutch Pancreatic Cancer Project; PACAP) according to the 'Trials within Cohorts' design. All PACAP participants with isolated local PDAC recurrence after primary resection who provided informed consent for being randomized in future studies are eligible. Patients will be randomized for local therapy (5 fractions of 8 Gy SBRT) in addition to standard of care or standard of care alone. In total, 174 patients will be included. The main study endpoint is survival after recurrence. The most important secondary endpoint is quality of life.

DISCUSSION

It is hypothesized that additional SBRT, compared to standard of care alone, improves survival and quality of life in patients with isolated local recurrence after PDAC resection.

TRIAL REGISTRATION

ClinicalTrials.gov registration NCT04881487 . Registered on May 11, 2021.

Stereotactic Body Radiotherapy (SBRT) of Pancreatic Cancer-A Critical Review and Practical Consideration

Pancreatic cancer is the third leading cause of cancer death in the developed world and is predicted to become the second by 2030. A cure may be achieved only with surgical resection of an early diagnosed disease. Surgery for more advanced disease is challenging and can be contraindicated for many reasons. Neoadjuvant therapy may improve the probability of achieving R0 resection. It consists of systemic treatment followed by radiation therapy applied concurrently or sequentially with cytostatics. A novel approach to irradiation, stereotactic body radiotherapy (SBRT), has the potential to improve treatment results. SBRT can deliver higher doses of radiation to the tumor in only a few treatment fractions. It has attracted significant interest for pancreatic cancer patients, as it is completed quickly, requires less time away from full-dose chemotherapy, and is well-tolerated than conventional radiotherapy. In this review, we aim to provide the reader with a basic overview of current evidence for SBRT indications in the treatment of pancreatic tumors. In the second part of the review, we focus on practical information with respect to SBRT treatment plan preparation the performance of such therapy. Finally, we discuss future directions related to the use of magnetic resonance linear accelerators.

Brachytherapy via a depot of biopolymer-bound 131I synergizes with nanoparticle paclitaxel in therapy-resistant pancreatic tumours

Locally advanced pancreatic tumours are highly resistant to conventional radiochemotherapy. Here we show that such resistance can be surmounted by an injectable depot of thermally responsive elastin-like polypeptide (ELP) conjugated with iodine-131 radionuclides (131I-ELP) when combined with systemically delivered nanoparticle albumin-bound paclitaxel. This combination therapy induced complete tumour regressions in diverse subcutaneous and orthotopic mouse models of locoregional pancreatic tumours. 131I-ELP brachytherapy was effective independently of the paclitaxel formulation and dose, but external beam radiotherapy (EBRT) only achieved tumour-growth inhibition when co-administered with nanoparticle paclitaxel. Histological analyses revealed that 131I-ELP brachytherapy led to changes in the expression of intercellular collagen and junctional proteins within the tumour microenvironment. These changes, which differed from those of EBRT-treated tumours, correlated with the improved delivery and accumulation of paclitaxel nanoparticles within the tumour. Our findings support the further translational development of 131I-ELP depots for the synergistic treatment of localized pancreatic cancer.

Pain Relief after Stereotactic Radiotherapy of Pancreatic Adenocarcinoma: An Updated Systematic Review

Severe pain is frequent in patients with locally advanced pancreatic ductal adenocarcinoma (PDCA). Stereotactic body radiotherapy (SBRT) provides high local control rates in these patients. The aim of this review was to systematically analyze the available evidence on pain relief in patients with PDCA. We updated our previous systematic review through a search on PubMed of papers published from 1 January 2018 to 30 June 2021. Studies with full available text, published in English, and reporting pain relief after SBRT on PDCA were included in this analysis. Statistical analysis was carried out using the MEDCALC statistical software. All tests were two-sided. The I2 statistic was used to quantify statistical heterogeneity (high heterogeneity level: >50%). Nineteen papers were included in this updated literature review. None of them specifically aimed at assessing pain and/or quality of life. The rate of analgesics reduction or suspension ranged between 40.0 and 100.0% (median: 60.3%) in six studies. The pooled rate was 71.5% (95% CI, 61.6−80.0%), with high heterogeneity between studies (Q2 test: p < 0.0001; I2 = 83.8%). The rate of complete response of pain after SBRT ranged between 30.0 and 81.3% (median: 48.4%) in three studies. The pooled rate was 51.9% (95% CI, 39.3−64.3%), with high heterogeneity (Q2 test: p < 0.008; I2 = 79.1%). The rate of partial plus complete pain response ranged between 44.4 and 100% (median: 78.6%) in nine studies. The pooled rate was 78.3% (95% CI, 71.0−84.5%), with high heterogeneity (Q2 test: p < 0.0001; I2 = 79.4%). A linear regression with sensitivity analysis showed significantly improved overall pain response as the EQD2α/β:10 increases (p: 0.005). Eight papers did not report any side effect during and after SBRT. In three studies only transient acute effects were recorded. The results of the included studies showed high heterogeneity. However, SBRT of PDCA resulted reasonably effective in producing pain relief in these patients. Further studies are needed to assess the impact of SBRT in this setting based on Patient-Reported Outcomes.

Neoadjuvant Stereotactic Body Radiotherapy After Upfront Chemotherapy Improves Pathologic Outcomes Compared With Chemotherapy Alone for Patients With Borderline Resectable or Locally Advanced Pancreatic Adenocarcinoma Without Increasing Perioperative Toxicity

BACKGROUND

Patients with borderline resectable pancreatic cancer (BRPC) or locally advanced pancreatic cancer (LAPC) are at high risk of margin-positive resection. Neoadjuvant stereotactic body radiation therapy (SBRT) may help sterilize margins, but its additive benefit beyond neoadjuvant chemotherapy (nCT) is unclear. The authors report long-term outcomes for BRPC/LAPC patients explored after treatment with either nCT alone or nCT followed by five-fraction SBRT (nCT-SBRT).

METHODS

Patients with BRPC or LAPC from 2011 to 2016 who underwent resection after nCT alone or nCT-SBRT were retrospectively reviewed. Baseline characteristics were compared, and the propensity score with inverse probability weighting (IPW) was used to compare pathologic/survival outcomes.

RESULTS

Of 198 patients, 76 received nCT, and 122 received nCT-SBRT. The nCT-SBRT cohort had a higher proportion of LAPC (53% vs 22%; p < 0.001). The duration of nCT was longer for nCT-SBRT (4.6 vs 2.9 months; p = 0.03), but adjuvant chemotherapy was less frequently administered (53% vs 67.1%; p < 0.001). Adjuvant radiation was administered to 30% of the nCT patients. The nCT-SBRT regimen more frequently achieved negative margins (92% vs 70%; p < 0.001), negative nodes (59% vs 42%; p < 0.001), and pathologic complete response (7% vs 0%; p = 0.02). In the multivariate analysis, nCT-SBRT remained associated with R0 resection (p < 0.001). The nCT-SBRT cohort experienced no significant difference in median overall survival (OS) (22.1 vs 24.5 months), local progression-free survival (LPFS) (13.5 vs. 15.4 months), or distant metastasis-free survival (DMFS) (11.7 vs 16.3 months) after surgery. After SBRT, 1-year OS was 77.0% and 2-year OS was 50.4%. Perioperative Claven-Dindo grade 3 or greater morbidity did not differ significantly between the nCT and nCT-SBRT cohorts (p = 0.81).

CONCLUSIONS

Despite having more advanced disease, the nCT-SBRT cohort was still more likely to undergo an R0 resection and experienced similar survival outcomes compared with the nCT alone cohort.

Stereotactic Body Radiation Therapy versus Concurrent Chemoradiotherapy for Locally Advanced Pancreatic Cancer: A Propensity Score-Matched Analysis

In locally advanced pancreatic cancer (LAPC), stereotactic body radiation therapy (SBRT) has been applied as an alternative to concurrent chemoradiotherapy (CCRT); however, direct comparative evidence between these two modalities is scarce. The aim of this study was to compare the clinical outcomes of SBRT with CCRT for LAPC. We retrospectively reviewed the medical records of patients with LAPC who received SBRT (n = 95) or CCRT (n = 66) with a concurrent 5-FU-based regimen between January 2008 and July 2016. The clinical outcomes of freedom from local progression (FFLP), progression-free survival (PFS), overall survival (OS), and toxicities were analyzed before and after propensity score (PS) matching. After a median follow-up duration of 15.5 months (range, 2.3-64.5), the median OS, PFS, and FFLP of the unmatched patients were 17.3 months, 11 months, and 19.6 months, respectively. After PS matching, there were no significant differences between the SBRT and CCRT groups in terms of the 1-year rates of OS (66.7% vs. 80%, p = 0.455), PFS (40.0% vs. 54.2%, p = 0.123), and FFLP (77.2% and 87.1%, p = 0.691). Our results suggest SBRT could be a feasible alternative to CCRT in treating patients with LAPC.

Stereotactic radiotherapy and the potential role of magnetic resonance-guided adaptive techniques for pancreatic cancer

BACKGROUND

Pancreatic cancer is a malignancy with one of the poorest prognoses amongst all cancers. Patients with unresectable tumours either receive palliative care or undergo various chemoradiotherapy regimens. Conventional techniques are often associated with acute gastrointestinal toxicities, as adjacent critical structures such as the duodenum ultimately limits delivered doses. Stereotactic body radiotherapy (SBRT) is an advanced radiation technique that delivers highly ablative radiation split into several fractions, with a steep dose fall-off outside target volumes.

AIM

To discuss the latest data on SBRT and whether there is a role for magnetic resonance-guided techniques in multimodal management of locally advanced, unresectable pancreatic cancer.

METHODS

We conducted a search on multiple large databases to collate the latest records on radiotherapy techniques used to treat pancreatic cancer. Out of 1229 total records retrieved from our search, 36 studies were included in this review.

RESULTS

Studies indicate that SBRT is associated with improved clinical efficacy and toxicity profiles compared to conventional radiotherapy techniques. Further dose escalation to the tumour with SBRT is limited by the poor soft-tissue visualisation of computed tomography imaging during radiation planning and treatment delivery. Magnetic resonance-guided techniques have been introduced to improve imaging quality, enabling treatment plan adaptation and re-optimisation before delivering each fraction.

CONCLUSION

Therefore, SBRT may lead to improved survival outcomes and safer toxicity profiles compared to conventional techniques, and the addition of magnetic resonance-guided techniques potentially allows dose escalation and conversion of unresectable tumours to operable cases.

Online adaptive MR-guided stereotactic radiotherapy for unresectable malignancies in the upper abdomen using a 1.5T MR-linac

BACKGROUND

Introduction of online adaptive MR-guided radiotherapy enables stereotactic body radiation therapy (SBRT) of upper abdominal tumors. This study aimed to evaluate the feasibility of MR-guided SBRT on a 1.5 T MR-linac in patients with unresectable upper abdominal malignancies.

MATERIAL AND METHODS

Patients treated at the UMC Utrecht (April 2019 to December 2020) were identified in the prospective 'Multi-OutcoMe EvaluatioN of radiation Therapy Using the MR-linac' (MOMENTUM) study. Feasibility of treatment was arbitrarily defined as an on-table time interval of ≤60 min for >75% of delivered fractions and completion of >95% of fractions as scheduled, reflecting patient tolerability. Acute treatment-related toxicity was assessed at 3 months of follow-up and graded according to the National Cancer Institute Common Terminology Criteria of Adverse Events version 5.0.

RESULTS

Twenty-five consecutive patients with a median follow-up time of 8 (range 4-23) months were treated with 35 Gray (n = 4) and 40 Gray (n = 21) in five fractions over 2 weeks. For all fractions, contours were adapted based on the daily anatomy and delivered within 47 min/fraction (range 30-74). In 98/117 fractions (84%), adapted treatment was completed within 1 h. All patients received the scheduled irradiation dose as planned. No acute grade 3 toxicity or higher was reported. Treatment resulted in pain alleviation in 11/13 patients.

DISCUSSION

Online adaptive MR-guided SBRT on a 1.5 T MR-linac is feasible and well-tolerated in patients with unresectable upper abdominal malignancies. Dose escalation studies, followed by comparative studies, are needed to determine the optimal radiation dose for irradiation of upper abdominal malignancies.

Simulated dose painting of hypoxic sub-volumes in pancreatic cancer stereotactic body radiotherapy

Dose painting of hypoxic tumour sub-volumes using positron-emission tomography (PET) has been shown to improve tumour controlin silicoin several sites, predominantly head and neck and lung cancers. Pancreatic cancer presents a more stringent challenge, given its proximity to critical gastro-intestinal organs-at-risk (OARs), anatomic motion, and impediments to reliable PET hypoxia quantification. A radiobiological model was developed to estimate clonogen survival fraction (SF), using¹⁸F-fluoroazomycin arabinoside PET (FAZA PET) images from ten patients with unresectable pancreatic ductal adenocarcinoma to quantify oxygen enhancement effects. For each patient, four simulated five-fraction stereotactic body radiotherapy (SBRT) plans were generated: (1) a standard SBRT plan aiming to cover the planning target volume with 40 Gy, (2) dose painting plans delivering escalated doses to a maximum of three FAZA-avid hypoxic sub-volumes, (3) dose painting plans with simulated spacer separating the duodenum and pancreatic head, and (4), plans with integrated boosts to geometric contractions of the gross tumour volume (GTV). All plans saturated at least one OAR dose limit. SF was calculated for each plan and sensitivity of SF to simulated hypoxia quantification errors was evaluated. Dose painting resulted in a 55% reduction in SF as compared to standard SBRT; 78% with spacer. Integrated boosts to hypoxia-blind geometric contractions resulted in a 41% reduction in SF. The reduction in SF for dose-painting plans persisted for all hypoxia quantification parameters studied, including registration and rigid motion errors that resulted in shifts and rotations of the GTV and hypoxic sub-volumes by as much as 1 cm and 10 degrees. Although proximity to OARs ultimately limited dose escalation, with estimated SFs (∼10^-5) well above levels required to completely ablate a ∼10 cm³tumour, dose painting robustly reduced clonogen survival when accounting for expected treatment and imaging uncertainties and thus, may improve local response and associated morbidity.

The role of radiotherapy in locally advanced pancreatic cancer

At diagnosis, about 15% of patients with pancreatic cancer present with a resectable tumour, 50% have a metastatic tumour, and 35% a locally advanced tumour, non-metastatic but unresectable due to vascular invasion, or borderline resectable. Despite the technical progress made in the field of radiation therapy and the improvement of the efficacy of chemotherapy, the prognosis of these patients remains very poor. Recently, the role of radiation therapy in the management of pancreatic cancer has been much debated. This review aims to evaluate the role of radiation therapy for patients with locally advanced tumours.

Survival outcome after stereotactic body radiotherapy for locally advanced and borderline resectable pancreatic cancer: A systematic review and meta-analysis

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For LAPC, median OS was 14.1 months; pooled 1/2/3-year OS rates were 57%, 19% and 10%.

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The median PFS was 10 months; pooled 1/2/3-year PFS rates were 36%, 12% and 4%.

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Pooled rates of acute GI, acute hematologic and late GI toxicities were 2%, 4% and 8%.

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For BRPC, median OS was 17.5 months; pooled 1/2-year OS rates were 75% and 29%.

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The median PFS was 12.2 months; pooled 1/2-year PFS rates were 48% and 18%.

Background

Some studies reported stereotactic body radiotherapy (SBRT) has demonstrated superior therapeutic results than conventional radiotherapy. Nevertheless, this statement is controversial and the trial attempting to prove this is underway. We conducted this systemic review and meta-analysis aiming to combine the latest and most complete information about the survival outcomes and toxicities following SBRT for locally advanced pancreatic cancer (LAPC) and borderline resectable pancreatic cancer (BRPC).

Methods

Items involving SBRT and pancreatic cancer were searched in PubMed, EMBASE, Cochrane Library, SCOPUS and Web of Science. Median overall survival (OS), 1/2/3-year OS, median progression-free survival (PFS), 1/2/3-year PFS and incidence of grade 3–5 toxicities were the endpoints of interest in this meta-analysis. These endpoint proportions were pooled and analyzed using R.

Results

For the LAPC series, the median OS was 14.1 months; pooled 1/2/3-year OS rates were 57%, 19% and 10%, respectively; the median PFS was 10 months; pooled 1/2/3-year PFS rates were 36%, 12% and 4%; pooled incidence rates of acute gastrointestinal (GI), acute hematologic and late GI toxicity (grade≥3) were 2%, 4% and 8%. For the BRPC series, the median OS was 17.5 months; pooled 1/2-year OS rates were 75% and 29%; the median PFS was 12.2 months; pooled 1/2-year PFS rates were 48% and 18%; the incidence rates of toxicity (grade ≥ 3) were all 0%.

Conclusions

Our meta-analysis based on published results of OS, PFS and incidence rates of toxicity demonstrated that SBRT does not show desirable therapeutic result than the standard therapies for LAPC and BRPC.

Maximizing Tumor Control and Limiting Complications With Stereotactic Body Radiation Therapy for Pancreatic Cancer

PURPOSE

Stereotactic body radiation therapy (SBRT) and stereotactic ablative body radiation therapy is being increasingly used for pancreatic cancer (PCa), particularly in patients with locally advanced and borderline resectable disease. A wide variety of dose fractionation schemes have been reported in the literature. This HyTEC review uses tumor control probability models to evaluate the comparative effectiveness of the various SBRT treatment regimens used in the treatment of patients with localized PCa.

METHODS AND MATERIALS

A PubMed search was performed to review the published literature on the use of hypofractionated SBRT (usually in 1-5 fractions) for PCa in various clinical scenarios (eg, preoperative [neoadjuvant], borderline resectable, and locally advanced PCa). The linear quadratic model with α/β= 10 Gy was used to address differences in fractionation. Logistic tumor control probability models were generated using maximum likelihood parameter fitting.

RESULTS

After converting to 3-fraction equivalent doses, the pooled reported data and associated models suggests that 1-year local control (LC) without surgery is ≈79% to 86% after the equivalent of 30 to 36 Gy in 3 fractions, showing a dose response in the range of 25 to 36 Gy, and decreasing to less than 70% 1-year LC at doses below 24 Gy in 3 fractions. The 33 Gy in 5 fraction regimen (Alliance A021501) corresponds to 28.2 Gy in 3 fractions, for which the HyTEC pooled model had 77% 1-year LC without surgery. Above an equivalent dose of 28 Gy in 3 fractions, with margin-negative resection the 1-year LC exceeded 90%.

CONCLUSIONS

Pooled analyses of reported tumor control probabilities for commonly used SBRT dose-fractionation schedules for PCa suggests a dose response. These findings should be viewed with caution given the challenges and limitations of this review. Additional data are needed to better understand the dose or fractionation-response of SBRT for PCa.

Stereotactic body radiotherapy vs conventionally fractionated chemoradiation in locally advanced pancreatic cancer: A multicenter case-control study (PAULA-1)

Conventionally fractionated chemoradiation (CRT) or chemotherapy (CHT) are considered as standard options in locally advanced pancreatic cancer (LAPC) while stereotactic body radiotherapy (SBRT) is an emerging treatment in this setting. The aim of this study was to compare two cohorts of LAPC patients treated with SBRT ± CHT vs CRT ± CHT in terms of local control (LC), distant metastases-free survival (DMFS), progression-free survival (PFS), overall survival (OS), and toxicity. Eighty patients were included. Patients in the two cohorts were matched according to: age ≤/>65 years, tumor diameter (two cut-offs: </≥3.0 and </≥3.9 cm), clinical tumor stage and clinical nodal stage, neoadjuvant CHT, and adjuvant CHT. Median prescribed total dose was 30.0 Gy (range: 18.0-37.5) and 54.0 Gy (18.0-63.0) in SBRT and CRT cohorts, respectively. Toxicity was evaluated by CTCAE v4.0 scale. Survival curves were calculated by Kaplan-Meier method. For hypothesis testing an equivalence and a non-inferiority test was calculated. No statistically significant differences in terms of acute and late toxicity, DMFS, PFS, and OS were recorded among the two cohorts. Median, 1-, and 2-year LC was: 16.0 months, 53.1%, and 40.5% in the CRT cohort and 22.0 months, 80.4%, and 49.8% in the SBRT cohort, respectively (P: .017). A statistically non-inferiority significance was recorded in terms of OS between CRT and SBRT (P = .031). Patients treated with SBRT showed higher LC rate and similar OS compared to CRT. Therefore, the design of confirmatory randomized studies comparing SBRT and CRT seems justified.

Novel strategies using modern radiotherapy to improve pancreatic cancer outcomes: toward a new standard?

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive solid tumours with an estimated 5-year overall survival rate of 7% for all stages combined. In this highly resistant disease that is located in the vicinity of many radiosensitive organs, the role of radiotherapy (RT) and indications for its use in this setting have been debated for a long time and are still under investigation. Although a survival benefit has yet to be clearly demonstrated for RT, it is the only technique, other than surgery, that has been demonstrated to lead to local control improvement. The adjuvant approach is now strongly challenged by neoadjuvant treatments that could spare patients with rapidly progressive systemic disease from unnecessary surgery and may increase free margin (R0) resection rates for those eligible for surgery. Recently developed dose-escalated RT treatments, designed either to maintain full-dose chemotherapy or to deliver a high biologically effective dose, particularly to areas of contact between the tumour and blood vessels, such as hypofractionated ablative RT (HFA-RT) or stereotactic body RT (SBRT), are progressively changing the treatment landscape. These modern strategies are currently being tested in prospective clinical trials with encouraging preliminary results, paving the way for more effective treatment combinations using novel targeted therapies. This review summarizes the current literature regarding the use of RT for the treatment of primary PDAC, describes the limitations of conventional RT, and discusses the emerging role of dose-escalated RT and heavy-particle RT.

Celiac Plexus Block After Stereotactic Body Radiotherapy Improves Pain Relief in Locally Advanced Pancreatic Cancer

Purpose

This study evaluated the analgesic effect of stereotactic body radiotherapy (SBRT) in combination with celiac plexus block (CPB), relative to SBRT alone, in locally advanced pancreatic cancer (LAPC) patients.

Patients and Methods

We reviewed medical records of all patients with LAPC, who received SBRT between 1 January 2017 to 31 August 2019 at our center. The average numeric rating scale (NRS) of ≥3 was used in all patients at admission. We recorded average and worst NRS in a 24-hour period, and daily narcotic doses before SBRT, followed by weekly for 1 month and monthly for 3 months.

Results

A total of 23 patients in the SBRT group and 12 under SBRT+CPB who met the inclusion criteria were enrolled. All patients in the SBRT+CPB group received CPB within 10 days after SBRT. Pain intensity and narcotic consumption were comparable in both groups at initial assessment. However, a significant decrease (P < 0.05) in average NRS was recorded in the SBRT+CPB group relative to SBRT at 2, 3 and 4 weeks after SBRT. A comparison of daily narcotic consumption with baseline values showed a significant decrease in the SBRT+CPB group at 3 and 4 weeks after SBRT (P < 0.05), while no significant differences were observed in the SBRT group.

Conclusion

CPB after SBRT appears to be an effective therapeutic option in patients with LAPC and warrants further evaluation with increased number of patients in prospective clinical trials.

Stereotactic robotic body radiotherapy for patients with oligorecurrent pulmonary metastases

BACKGROUND

Our aim is to report treatment efficacy and toxicity of patients treated by robotic (Cyberknife®) stereotactic body radiotherapy (SBRT) for oligorecurrent lung metastases (ORLM). Additionally we wanted to evaluate influence of tumor, patient and treatment related parameters on local control (LC), lung and distant progression free- (lung PFS/Di-PFS) and overall survival (OS).

METHODS

Consecutive patients with up to 5 ORLM (confirmed by FDG PET/CT) were included in this study. Intended dose was 60Gy in 3 fractions (prescribed to the 80% isodose volume). Patients were followed at regular intervals and tumor control and toxicity was prospectively scored. Tumor, patient and treatment data were analysed using competing risk- and Cox regression.

RESULTS

Between May 2010 and March 2016, 104 patients with 132 lesions were irradiated from primary lung carcinoma (47%), gastro-intestinal (34%) and mixed primary histologies (19%). The mean tumor volume was 7.9 cc. After a median follow up of 22 months, the 1, 2 and 3 year LC rate (per lesion) was 89.3, 80.0 and 77.8% respectively. The corresponding (per patient) 1, 2 and 3 years lung PFS were 66.3, 50.0, 42.6%, Di-PFS were 80.5, 64.4, 60.6% and OS rates were 92.2, 80.9 and 72.0% respectively. On univariable analysis, gastro-intestinal (GI) as primary tumor site showed a significant superior local control versus the other primary tumor sites. For OS, significant variables were primary histology and primary tumor site with a superior OS for patients with metastases of primary GI origin. LC was significantly affected by the tumor volume, physical and biologically effective dose coverage. Significant variables in multivariable analysis were BED prescription dose for LC and GI as primary site for OS. The vast majority of patients developed no toxicity or grade 1 acute and late toxicity. Acute and late grade 3 radiation pneumonitis (RP) was observed in 1 and 2 patients respectively. One patient with a centrally located lesion developed grade 4 RP and died due to possible RT-induced pulmonary hemorrhage.

CONCLUSIONS

SBRT is a highly effective local therapy for oligorecurrent lung metastases and could achieve long term survival in patients with favourable prognostic features.

Low rates of specialized cancer consultation and cancer-directed therapy for noncurable pancreatic adenocarcinoma: a population-based analysis

BACKGROUND

Although advancements in systemic therapy have improved the outlook for pancreatic adenocarcinoma, it is not known if patients get access to these therapies. We aimed to examine the patterns and factors associated with access to specialized cancer consultations and subsequent receipt of cancer-directed therapy for patients with non-curative pancreatic adenocarcinoma.

METHODS

We conducted a population-based analysis of noncurative pancreatic adenocarcinoma diagnosed over 2005-2016 in Ontario by linking administrative health care data sets. Our primary outcomes were specialized cancer consultation and receipt of cancer-directed therapy (chemotherapy or a combination of chemo- and radiation therapy [chemoradiation therapy]). We examined specialized cancer consultation with hepato-pancreatico-biliary surgery, medical and radiation oncology. We used multivariable logistic regression to identify factors associated with medical oncology consultation and cancer-directed therapy.

RESULTS

Of 10 881 patients, 64.9% had a consultation with specialists in medical oncology, 35.1% with hepatopancreatico-biliary surgery and 24.7% with radiation oncology. Sociodemographic characteristics were not associated with the likelihood of medical oncology consultation. Of these patients, 4144 received cancer-directed therapy, representing 38.1% of all patients and 58.6% of those who consulted with medical oncology. Of 6737 patients not receiving cancer-directed therapy, 2988 (44.4%) had a consultation with medical oncology. Older age and lowest income quintile were independently associated with lower likelihood of cancer-directed therapy. If the first specialized cancer consultation was with medical or radiation oncology, the likelihood of cancer-directed therapy was significantly higher compared with surgery.

INTERPRETATION

A considerable proportion of patients with noncurable pancreatic adenocarcinoma in Ontario did not have a specialized cancer consultation and most did not receive cancer-directed therapy. We identified disparities in specialized cancer consultation and receipt of systemic cancer-directed therapy that indicate potential gaps in assessment.

Clinical outcomes and prognostic factors of stereotactic body radiation therapy combined with gemcitabine plus capecitabine for locally advanced unresectable pancreatic cancer

PURPOSE

This study aimed to evaluate the clinical outcomes, toxicity, and prognostic factors of SBRT combined with gemcitabine plus capecitabine (GEM-CAP) in treating locally advanced pancreatic cancer (LAPC).

METHODS

A total of 56 patients with LAPC treated with SBRT combined with GEM-CAP were reviewed from October 2010 to October 2016. The median total prescription dose at five fractions was 40 Gy (30-50 Gy). The patients were subjected to two cycles of GEM-CAP before SBRT. GEM-CAP chemotherapy was then offered for four cycles or until disease tolerance or progression. The primary endpoints included overall survival (OS) and progression-free survival (PFS).

RESULTS

The median OS and PFS from the date of diagnosis was 19 (95% CI 14.6-23.4) and 12 months (95% CI 8.34-15.66), respectively. The 1-year and 2-year survival rates were 82.1% and 35.7%, whereas the 1-year and 2-year PFS rates were 48.2% and 14.3%, respectively. The median carbohydrate antigen 19-9-determined PFS time was 11 months (95% CI 5.77-16.24). Multivariate analysis demonstrated that tumor diameter, lymph node metastasis, pre-treatment CA19-9 level, and post-treatment CA19-9 decline were independent prognostic factors (p < 0.05). Acute toxicity was minimal, with two cases (3.6%) experiencing grade 3 duodenal obstruction. No adverse events greater than grade 3 occurred. In late toxicity, three patients (5.4%) developed grade 3 gastrointestinal toxicity and two (3.6%) suffered from perforation caused by grade 4 radiation enteritis and intestinal fistula.

CONCLUSIONS

The combination of Cyberknife SBRT and GEM-CAP achieved excellent efficacy with acceptable toxicity for LAPC.

Ablative radiation therapy for locally advanced pancreatic cancer: techniques and results

Standard doses of conventionally fractionated radiation have had minimal to no impact on the survival duration of patients with locally advanced unresectable pancreatic cancer (LAPC). The use of low-dose stereotactic body radiation (SBRT) in 3- to 5-fractionshas thus far produced a modest improvement in median survival with minimal toxicity and shorter duration of treatment, but failed to produce a meaningful difference at 2 years and beyond. A much higher biologically effective dose (BED) is likely needed to achieve tumor ablation The challenge is the delivery of ablative doses near the very sensitive gastrointestinal tract. Advanced organ motion management, image guidance, and adaptive planning techniques enable delivery of ablative doses of radiation (> = 100Gy BED) when more protracted hypofractionated regimens or advanced image guidance and adaptive planning are used. This approach has resulted in encouraging improvements in survival in several studies. This review will summarize the evolution of the radiation technique over time from conventional to ablative and describe the practical aspects of delivering ablative doses near the GI tract using cone beam CT image (CBCT) guidance and online adaptive MRI guidance.

Outcome of head compared to body and tail pancreatic cancer: a systematic review and meta-analysis of 93 studies

Background

Even when resectable pancreatic cancer (PC) is associated with a dismal prognosis. Initial presentation varies according with primary tumor location. Aim of this systematic review and meta-analysis was to evaluate the prognosis associated with site (head versus body/tail) in patients with PC.

Methods

We searched PubMed, Cochrane Library, SCOPUS, Web of Science, EMBASE, Google Scholar, LILACS, and CINAHL databases from inception to March 2018. Studies reporting information on the independent prognostic role of site in PC and comparing overall survival (OS) in head versus body/tail tumors were selected. Data were aggregated using hazard ratios (HRs) for OS of head versus body/tail PC according to fixed- or random-effect model.

Results

A total of 93 studies including 254,429 patients were identified. Long-term prognosis of head was better than body/tail cancers (HR =0.96, 95% CI: 0.92-0.99; P=0.02). A pooled HR of 0.95 (95% CI: 0.92-0.99, P=0.02) from multivariate analysis only (n=77 publications) showed that head site was an independent prognostic factor for survival.

Conclusions

Primary tumor location in the head of the pancreas at the time of diagnosis is a predictor of better survival. Such indicator should be acknowledged when designing future studies, in particular in the operable and neoadjuvant setting.

Effectiveness and Safety of Simultaneous Integrated Boost-Proton Beam Therapy for Localized Pancreatic Cancer

Purpose:

To evaluate the clinical effectiveness and feasibility of simultaneous integrated boost-proton beam therapy in patients with localized pancreatic cancer.

Methods:

Thirty-seven patients with localized pancreatic cancer underwent simultaneous integrated boost-proton beam therapy, and 8 (21.6%) patients received induction chemotherapy. The internal target volume was obtained by summing the gross tumor volumes in exhalation phase computed tomography images. Planning target volume 1 included internal target volume plus 3 to 5 mm margins, excluding the 5 mm expanded volume of gastrointestinal structures, and planning target volume 2 included the internal target volume plus 7 to 12 mm margins. The prescribed doses to planning target volume 1 and planning target volume 2 were 45 GyE (equivalent dose in 2 Gy, 54.4 GyE₁₀) and 30 GyE (equivalent dose in 2 Gy, 32.5 GyE₁₀) in 10 fractions, respectively.

Results:

Overall, treatment was well tolerated, with no grade of toxicity ≥3. Median overall survival was 19.3 months, and 1-year local progression-free survival, relapse-free survival, and overall survival rates were 64.8%, 33.2%, and 75.7%, respectively. Patients treated with simultaneous integrated boost-proton beam therapy after induction chemotherapy had a significantly higher median overall survival time compared to those with simultaneous integrated boost-proton beam therapy alone (21.6 months vs 16.7 months, P = .031). Multivariate analysis showed that induction chemotherapy was a significant factor for overall survival (P < .05).

Conclusions:

Simultaneous integrated boost-proton beam therapy could be feasible and promising for patients with localized pancreatic cancer.

Stereotactic body radiation therapy for palliative management of pancreatic adenocarcinoma in elderly and medically inoperable patients

Stereotactic body radiation therapy (SBRT) represents a promising treatment option for patients with localized pancreatic ductal adenocarcinoma (PDAC) who cannot tolerate surgical therapy. We retrospectively reviewed the records of patients with localized PDAC treated with SBRT at our institution between 2010 and 2016 to identify patients deemed medically inoperable due to poor performance status, advanced age, and/or comorbid conditions. Overall survival (OS), progression-free survival (PFS), and local progression-free survival (LPFS) were estimated using Kaplan-Meier curves. Twenty-nine patients were included. Median age was 74 (IQR 68-79). Thirteen patients (45%) had an Eastern Cooperative Oncology Group performance status of 2. Six patients (19%) had chronic obstructive pulmonary disease, 9 (31%) had cardiovascular disease, and 17 (58%) had diabetes mellitus. SBRT was delivered over 5 fractions to a median dose of 28 Gy (IQR, 25-33). Twenty-two patients (76%) received induction chemotherapy prior to SBRT, and 9 (31%) received maintenance chemotherapy after SBRT. Median OS was 13 months from diagnosis. Median OS and PFS were 8 and 6 months from SBRT, respectively. Six and 12-month LPFS rates were 91% and 78%, respectively. Patients receiving induction chemotherapy had superior survival from diagnosis than those who did not (14 vs. 7 months, p = 0.01). Three patients (10%) experienced acute grade ≥3 toxicity, and 1 patient (4%) experienced grade ≥3 late toxicity. Symptom relief was achieved at three-month follow-up in 8 of 11 patients (73%) experiencing abdominal pain. These results suggest SBRT may be safe and effective for patients who cannot tolerate surgery.