Clinical and Dosimetric Impact of 2D kV Motion Monitoring and Intervention in Liver Stereotactic Body Radiation Therapy

Purpose

Positional errors resulting from motion are a principal challenge across all disease sites in radiation therapy. This is particularly pertinent when treating lesions in the liver with stereotactic body radiation therapy (SBRT). To achieve dose escalation and margin reduction for liver SBRT, kV real-time imaging interventions may serve as a potential solution. In this study, we report results of a retrospective cohort of liver patients treated using real-time 2D kV-image guidance SBRT with emphasis on the impact of (1) clinical workflow, (2) treatment accuracy, and (3) tumor dose.

Methods and Materials

Data from 33 patients treated with 41 courses of liver SBRT were analyzed. During treatment, planar kV images orthogonal to the treatment beam were acquired to determine treatment interventions, namely treatment pauses (ie, adequacy of gating thresholds) or treatment shifts. Patients were shifted if internal markers were >3 mm, corresponding to the PTV margin used, from the expected reference condition. The frequency, duration, and nature of treatment interventions (ie, pause vs shift) were recorded, and the dosimetric impact associated with treatment shifts was estimated using a machine learning dosimetric model.

Results

Of all fractions delivered, 39% required intervention, which took on average 1.9 ± 1.6 minutes and occurred more frequently in treatments lasting longer than 7 minutes. The median realignment shift was 5.7 mm in size, and the effect of these shifts on minimum tumor dose in simulated clinical scenarios ranged from 0% to 50% of prescription dose per fraction.

Conclusion

Real-time kV-based imaging interventions for liver SBRT minimally affect clinical workflow and dosimetrically benefit patients. This potential solution for addressing positional errors from motion addresses concerns about target accuracy and may enable safe dose escalation and margin reduction in the context of liver SBRT.

Pilot Curriculum for Continued Professional Development of Radiation Oncology Nurses

Purpose

Limited structured educational programs are available for the continued professional development of radiation oncology nurses. In this study, we evaluated a pilot curriculum focusing on clinical workflow and toxicity management for radiation oncology nurses at a single university-affiliated medical center network.

Methods and Materials

Based on a previous multi-institutional needs assessment, a targeted curriculum on clinical workflow and toxicity management was developed, including didactic lectures, written disease-specific toxicity management guidelines, and standardized medication/laboratory order preference lists in the electronic health record. An anonymized survey was circulated to all participants pre- and postcurriculum. The survey was composed of Likert-type subjective questions and 11 objective knowledge-based questions (KBQs). Paired Likert-type data were analyzed using Wilcoxon signed ranks test. Objective question data were compared with the McNamar's mid P test.

Results

Thirteen nurses participated in the pilot curriculum and 100% completed pre- and post curriculum surveys. After the didactics, nurses reported a significant increase in their understanding of the responsibilities of a nurse and overall process of care and their ability to explain computed tomography simulation, as well as their ability to assess, manage, and grade radiation-related toxicities (P < .01). There was significant improvement in the percent of correct answers on objective KBQs from a baseline of 52% to 80% after the curriculum (P < .01). Qualitatively, 70% (9/13) of nurses rated the curriculum as "extremely useful" and 30% (4/13) as "quite useful."

Conclusions

Our pilot curriculum using a combination of in-person formal didactics, toxicity management guidelines, and electronic health record based order preference lists was well-received and showed promising results on KBQ assessment. This work may be used to guide the development of larger curricula for nurse onboarding and continuing education in a multicenter setting.

Cardiovascular Mortality and Duration of Androgen Deprivation in Locally Advanced Prostate Cancer: Long-term Update of NRG/RTOG 9202

BACKGROUND

Androgen deprivation therapy (ADT) has been associated with coronary heart disease and myocardial infarction (MI) in prostate cancer patients, but controversy persists regarding its effects on cardiovascular mortality (CVM).

OBJECTIVE

We assessed the long-term relationship between ADT and CVM in a prostate cancer randomized trial (NRG Oncology/Radiation Therapy Oncology Group 9202).

DESIGN, SETTING, AND PARTICIPANTS

From 1992 to 1995, 1554 men with locally advanced prostate cancer (T2c-T4, prostate-specific antigen <150 ng/ml) received radiotherapy with 4 mo (short-term [STADT]) versus 28 mo (longer-term [LTADT]) of ADT.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Using the Fine-Gray and Cox regression models, the relationship between ADT and mortality was evaluated.

RESULTS AND LIMITATIONS

With a median follow-up of 19.6 yr, LTADT was associated with improved overall survival (OS) versus STADT (adjusted hazard ratio [HR] 0.88; p = 0.03) and prostate cancer survival (subdistribution HR [sHR] 0.70, p = 0.003). Comparing LTADT with STADT, prostate cancer mortality improved by 6.0% (15.6% [95% confidence interval 13.0-18.3%] vs 21.6% [18.6-24.7%]) at 15 yr, while CVM increased by 2.2% (14.9% [12.4-17.6%] vs 12.7% [10.4-15.3%]). In multivariable analyses, LTADT was not associated with increased CVM versus STADT (sHR 1.22 [0.93-1.59]; p = 0.15). An association between LTADT and MI death was detected (sHR 1.58 [1.00-2.50]; p = 0.05), particularly in patients with prevalent cardiovascular disease (CVD; sHR 2.54 [1.16-5.58]; p = 0.02).

CONCLUSIONS

With 19.6 yr of follow-up, LTADT was not significantly associated with increased CVM in men with locally advanced prostate cancer. Patients may have increased MI mortality with LTADT, particularly those with baseline CVD. Overall, there remained a prostate cancer mortality benefit and no OS detriment with LTADT.

PATIENT SUMMARY

In a long-term analysis of a large randomized prostate cancer trial, radiation with 28 mo of hormone therapy did not increase the risk of cardiovascular death significantly versus 4 mo of hormone therapy. Future studies are needed for patients with pre-existing heart disease, who may have an increased risk of myocardial infarction death with longer hormone use.

The American Brachytherapy Society and Indian Brachytherapy Society consensus statement for the establishment of high-dose-rate brachytherapy programs for gynecological malignancies in low- and middle-income countries

PURPOSE

The global cervical cancer burden is disproportionately high in low- and middle-income countries (LMICs), and outcomes can be governed by the accessibility of appropriate screening and treatment. High-dose-rate (HDR) brachytherapy plays a central role in cervical cancer treatment, improving local control and overall survival. The American Brachytherapy Society (ABS) and Indian Brachytherapy Society (IBS) collaborated to provide this succinct consensus statement guiding the establishment of brachytherapy programs for gynecological malignancies in resource-limited settings.

METHODS AND MATERIALS

ABS and IBS members with expertise in brachytherapy formulated this consensus statement based on their collective clinical experience in LMICs with varying levels of resources.

RESULTS

The ABS and IBS strongly encourage the establishment of HDR brachytherapy programs for the treatment of gynecological malignancies. With the consideration of resource variability in LMICs, we present 15 minimum component requirements for the establishment of such programs. Guidance on these components, including discussion of what is considered to be essential and what is considered to be optimal, is provided.

CONCLUSIONS

This ABS/IBS consensus statement can guide the successful and safe establishment of HDR brachytherapy programs for gynecological malignancies in LMICs with varying levels of resources.

Comparison of first-line radiosurgery for small-cell and non-small cell lung cancer brain metastases (CROSS-FIRE)

INTRODUCTION

Historical reservations regarding stereotactic radiosurgery (SRS) for small-cell lung cancer (SCLC) brain metastases include concerns for short-interval and diffuse central nervous system (CNS) progression, poor prognoses, and increased neurological mortality specific to SCLC histology. We compared SRS outcomes for SCLC and non-small cell lung cancer (NSCLC) where SRS is well established.

METHODS

Multicenter first-line SRS outcomes for SCLC and NSCLC from 2000 to 2022 were retrospectively collected (n = 892 SCLC, n = 4785 NSCLC). Data from the prospective Japanese Leksell Gamma Knife Society (JLGK0901) clinical trial of first-line SRS were analyzed as a comparison cohort (n = 98 SCLC, n = 814 NSCLC). Overall survival (OS) and CNS progression were analyzed using Cox proportional hazard and Fine-Gray models, respectively, with multivariable adjustment for cofactors including age, sex, performance status, year, extracranial disease status, and brain metastasis number and volume. Mutation-stratified analyses were performed in propensity score-matched retrospective cohorts of epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) positive NSCLC, mutation-negative NSCLC, and SCLC.

RESULTS

OS was superior for patients with NSCLC compared to SCLC in the retrospective dataset (median OS = 10.5 vs 8.6 months; P < .001) and in the JLGK0901 dataset. Hazard estimates for first CNS progression favoring NSCLC were similar in both datasets but reached statistical significance in the retrospective dataset only (multivariable hazard ratio = 0.82, 95% confidence interval = 0.73 to 0.92, P = .001). In the propensity score-matched cohorts, there were continued OS advantages for NSCLC patients (median OS = 23.7 [EGFR and ALK positive NSCLC] vs 13.6 [mutation-negative NSCLC] vs 10.4 months [SCLC], pairwise P values < 0.001), but no statistically significant differences in CNS progression were observed in the matched cohorts. Neurological mortality and number of lesions at CNS progression were similar for NSCLC and SCLC patients. Leptomeningeal progression was increased in patients with NSCLC compared to SCLC in the retrospective dataset only (multivariable hazard ratio = 1.61, 95% confidence interval = 1.14 to 2.26, P = .007).

CONCLUSIONS

After SRS, SCLC histology was associated with shorter OS compared to NSCLC. CNS progression occurred earlier in SCLC patients overall but was similar in patients matched on baseline factors. SCLC was not associated with increased neurological mortality, number of lesions at CNS progression, or leptomeningeal progression compared to NSCLC. These findings may better inform clinical expectations and individualized decision making regarding SRS for SCLC patients.

Fiducial Markers Allow Accurate and Reproducible Delivery of Liver Stereotactic Body Radiation Therapy

Fiducial markers are utilized for image guided radiotherapy (IGRT) alignment during the delivery of liver stereotactic body radiosurgery (SBRT). There are limited data demonstrating the impact of matching fiducials on the accuracy of liver SBRT. This study quantifies the benefit of fiducial-based alignment and improvements in inter-observer reliability. Nineteen patients with 24 liver lesions were treated with SBRT. Target localization was performed using fiducial markers on cone-beam computed tomography (CBCT). Each CBCT procedure was retrospectively realigned to match both the liver edge and fiducial markers. The shifts were recorded by seven independent observers. Inter-observer variability was analyzed by calculating the mean error and uncertainty for the set-up. The mean absolute Cartesian error observed from fiducial and liver edge-based alignment was 1.5 mm and 5.3 mm, respectively. The mean uncertainty from fiducial and liver edge-based alignment was 1.8 mm and 4.5 mm, respectively. An error of 5 mm or greater was observed 50% of the time when aligning to the liver surface versus 5% of the time when aligning to fiducial markers. Aligning to the liver edge significantly increased the error, resulting in increased shifts when compared to alignment to fiducials. Tumors of 3 cm or farther from the liver dome had higher mean errors when aligned without fiducials (4.8 cm vs. 4.4 cm, p = 0.003). Our data support the use of fiducial markers for safer and more accurate liver SBRT.

Multicenter analysis of stereotactic radiosurgery for multiple brain metastases from EGFR and ALK driven non-small cell lung cancer

INTRODUCTION

Patients with brain metastases (BrMs) arising from EGFR and ALK driven non-small cell lung cancer (NSCLC) have favorable prognoses and evolving treatment options. We evaluated multicenter outcomes for stereotactic radiosurgery (SRS) to multiple (≥4) BrMs, where randomized data remain limited.

METHODS

Data were collected retrospectively from 5 academic centers on EGFR and ALK NSCLC who received SRS to ≥4 BrMs with their first SRS treatment between 2008 and 2018. Analyzed endpoints included overall survival (OS), freedom from CNS progression (FFCNSP), and freedom from whole-brain radiotherapy (FFWBRT).

RESULTS

Eighty-nine patients (50 EGFR, 39 ALK) received a total of 159 SRS treatments to 1,080 BrMs, with a median follow up of 51.3 months. The median number of BrMs treated with SRS treatment-1 was 6 (range 4-26) and median for all treatments was 9 (range 4-47). Sixteen patients (18 %) had received WBRT prior to SRS treatment-1. The median OS was 24.2, 21.2, and 33.2 months for all patients, EGFR, and ALK subsets, respectively. After multivariable adjustment, only receipt of a next-generation tyrosine kinase inhibitor was associated with OS (HR 0.40, p = 0.005). No differences in OS were observed based on number of BrMs treated. The median FFCNSP was 9.4, 11.6, and 7.5 months, for all patients, EGFR, and ALK subsets, respectively. After multivariable adjustment, the number of BrMs (continuous) treated during treatment-1 was the only negative prognostic factor associated with FFCNSP (HR 1.071, p = 0.045). The 5-year FFWBRT was 73.6 %.

CONCLUSIONS

This multicenter analysis over a >10-year period demonstrated favorable OS, FFCNSP, and FFWBRT, in patients with EGFR and ALK driven NSCLC receiving SRS to ≥4 BrMs. These data support SRS as an option in the upfront and salvage setting for higher burden CNS disease in this population.

Practical Implementation of Emergent After-Hours Radiation Treatment Process Using Remote Treatment Planning on Optimized Diagnostic CT Scans

The purpose of this report is to present the implementation of a process for after-hours radiation treatment (RT) utilizing remote treatment planning based on optimized diagnostic computed tomography (CT) scans for the urgent palliative treatment of inpatients. A standardized operating procedure was developed by an interprofessional panel to improve the quality of after-hours RT and minimize the risk of treatment errors. A new diagnostic CT protocol was created that could be performed after-hours on hospital scanners and would ensure a reproducible patient position and adequate field of view. An on-call structure for dosimetry staff was created utilizing remote treatment planning. The optimized CT protocol was developed in collaboration with the radiology department, and a novel order set was created in the electronic health system. The clinical workflow begins with the radiation oncologist notifying the on-call team (therapist, dosimetrist, and physicist) and obtaining an optimized diagnostic CT scan on a hospital-based scanner. The dosimetrist remotely creates a plan; the physicist checks the plan; and the patient is treated. Plans are intentionally simple (parallel opposed fields, symmetric jaws) to expedite care and reduce the risk of error. Education on the new process was provided for all relevant staff. Our process was successfully implemented with the use of an optimized CT protocol and remote treatment planning. This approach has the potential to improve the quality and safety of emergent after-hours RT by better approximating the normal process of care.

Brachytherapy in children, adolescents, and young adults: An underutilized modality in the United States?

BACKGROUND

Brachytherapy (BT) delivers highly conformal radiation and spares surrounding tissues, which may limit late effects in pediatric, adolescent, and young adult (AYA) patients. We aimed to characterize trends in BT use for this population in the United States, focusing on patients with rhabdomyosarcoma (RMS).

METHODS

The National Cancer Database was queried to identify patients ≤ 21 who were treated for solid tumor malignancies in the United States from 2004 to 2016. We obtained disease, treatment, and outcome data for patients treated with BT, in particular for RMS.

RESULTS

99 506 pediatric and AYA patients met study inclusion. Of these, 22 586 (23%) received radiation therapy (external beam radiation therapy [EBRT] and/or BT) and 240 (0.2%) received BT. Among patients treated with BT, 139 (58%) underwent surgery and 58 (24%) received EBRT. A total of 3836 patients were treated for RMS during this period. Of these, 2531 (66%) received any radiation and 37 (1%) received BT (EBRT + BT in 3, BT in 34). Of patients treated with BT for RMS, 28 (76%) underwent surgery + BT. Survival data were available for 31 patients treated with BT for RMS. With a median follow-up of 63 months, overall survival was 100% for patients with RMS of a favorable site treated with BT.

CONCLUSIONS

BT is rarely used to treat pediatric and AYA patients in the United States. Patients treated with BT for RMS experienced favorable survival, suggesting that this approach may not compromise oncologic outcomes and warrants further study as a therapeutic option in pediatric and AYA patients, specifically in RMS.

Prostate Cancer in Older Adults: Risk of Clinically Meaningful Disease, the Role of Screening and Special Considerations

PURPOSE OF REVIEW

Prostate cancer is the second most common cancer in men in the USA and several studies suggest more aggressive disease in older patients. However, screening remains controversial, especially in the older patient population.

RECENT FINDINGS

Aggressive prostate cancers are more common in older men. Screening trial results are conflicting but data suggest an improvement in prostate cancer mortality and increased detection of metastatic disease with screening. When PSA is utilized with multiparametric MRI and biomarker assays, patients at significant risk of clinically meaningful prostate cancer can be appropriately selected for biopsy. A thoughtful and individualized approach is central when considering prostate cancer screening in older men. This approach includes life expectancy estimation, use of appropriate geriatric assessment tools, use of multiparametric MRI and biomarkers in addition to PSA, and most importantly shared decision-making with patients.

Narrative review of immune checkpoint inhibitors and radiation therapy for brain metastases

Radiation therapy plays a key role in the management of intracranial metastatic disease. Historically, systemic therapy was able to address extracranial disease but not cross the blood-brain barrier and radiation therapy and surgery were the only mechanisms to treat intracranial metastases. There are now several examples of contemporary systemic therapies with central nervous system efficacy in some patients. With such improvements in systemic therapies, patients are living longer and the optimal management of brain metastases is becoming an increasingly important clinical priority. However, the role of radiation therapy remains critical in treating brain metastases. The concurrent use of new systemic therapies with radiation brings about novel and significant questions regarding potential synergy between these therapies in the brain in regard to both oncologic efficacy and toxicity. One important systemic therapy to consider is immune checkpoint inhibitors. These drugs are now at the forefront of management of many malignancies and have changed the landscape of treatment for many common cancers, particularly those with a predilection for brain metastases. In this review we will examine the existing data on the efficacy and toxicity of concurrent radiation therapy and immunotherapy for brain metastases and explore potential mechanisms underlying the published clinical observations.

Evaluation of First-line Radiosurgery vs Whole-Brain Radiotherapy for Small Cell Lung Cancer Brain Metastases: The FIRE-SCLC Cohort Study

Importance

Although stereotactic radiosurgery (SRS) is preferred for limited brain metastases from most histologies, whole-brain radiotherapy (WBRT) has remained the standard of care for patients with small cell lung cancer. Data on SRS are limited.

Objective

To characterize and compare first-line SRS outcomes (without prior WBRT or prophylactic cranial irradiation) with those of first-line WBRT.

Design, Setting, and Participants

FIRE-SCLC (First-line Radiosurgery for Small-Cell Lung Cancer) was a multicenter cohort study that analyzed SRS outcomes from 28 centers and a single-arm trial and compared these data with outcomes from a first-line WBRT cohort. Data were collected from October 26, 2017, to August 15, 2019, and analyzed from August 16, 2019, to November 6, 2019.

Interventions

SRS and WBRT for small cell lung cancer brain metastases.

Main Outcomes and Measures

Overall survival, time to central nervous system progression (TTCP), and central nervous system (CNS) progression-free survival (PFS) after SRS were evaluated and compared with WBRT outcomes, with adjustment for performance status, number of brain metastases, synchronicity, age, sex, and treatment year in multivariable and propensity score-matched analyses.

Results

In total, 710 patients (median [interquartile range] age, 68.5 [62-74] years; 531 men [74.8%]) who received SRS between 1994 and 2018 were analyzed. The median overall survival was 8.5 months, the median TTCP was 8.1 months, and the median CNS PFS was 5.0 months. When stratified by the number of brain metastases treated, the median overall survival was 11.0 months (95% CI, 8.9-13.4) for 1 lesion, 8.7 months (95% CI, 7.7-10.4) for 2 to 4 lesions, 8.0 months (95% CI, 6.4-9.6) for 5 to 10 lesions, and 5.5 months (95% CI, 4.3-7.6) for 11 or more lesions. Competing risk estimates were 7.0% (95% CI, 4.9%-9.2%) for local failures at 12 months and 41.6% (95% CI, 37.6%-45.7%) for distant CNS failures at 12 months. Leptomeningeal progression (46 of 425 patients [10.8%] with available data) and neurological mortality (80 of 647 patients [12.4%] with available data) were uncommon. On propensity score-matched analyses comparing SRS with WBRT, WBRT was associated with improved TTCP (hazard ratio, 0.38; 95% CI, 0.26-0.55; P < .001), without an improvement in overall survival (median, 6.5 months [95% CI, 5.5-8.0] for SRS vs 5.2 months [95% CI, 4.4-6.7] for WBRT; P = .003) or CNS PFS (median, 4.0 months for SRS vs 3.8 months for WBRT; P = .79). Multivariable analyses comparing SRS and WBRT, including subset analyses controlling for extracranial metastases and extracranial disease control status, demonstrated similar results.

Conclusions and Relevance

Results of this study suggest that the primary trade-offs associated with SRS without WBRT, including a shorter TTCP without a decrease in overall survival, are similar to those observed in settings in which SRS is already established.

Radiosurgery for small-cell lung cancer brain metastases: a review

First-line stereotactic radiosurgery (SRS) is now considered the preferred treatment over whole brain radiation therapy (WBRT) for limited brain metastases arising from most tumor histologies. This standard was reached following the consistent results of multiple phase III studies which demonstrated that, despite improved CNS control, the addition of WBRT to SRS does not improve overall survival (OS) and is associated with a reduction in cognitive function. Thus, it may be reasonable to consider the benchmark necessary to favor a paradigm of SRS alone over strategies incorporating WBRT as the demonstration of comparable OS in the context of decreased treatment-related side effects. However, patients with small-cell lung cancer (SCLC) brain metastases were excluded from the landmark trials that established SRS alone for limited brain metastases, largely due to concerns for short-interval CNS progression in SCLC as well the historic role of prophylactic cranial irradiation (PCI) in SCLC in the absence of known brain metastases. As a result, WBRT has remained the standard for SCLC for limited and even solitary brain lesions. With shifting SCLC care patterns including increased MRI surveillance, decreased PCI delivery, and emerging systemic agents, interest in first-line SRS for SCLC is likely to continue to increase over time. Herein we will review the emerging data for first-line SRS in the management of SCLC brain metastases and the potential for its increasing role in the setting of a greater utilization of MRI surveillance and improving systemic therapies.

Combination of Trastuzumab Emtansine and Stereotactic Radiosurgery Results in High Rates of Clinically Significant Radionecrosis and Dysregulation of Aquaporin-4

PURPOSE

Patients with human EGFR2-positive (HER2⁺) breast cancer have a high incidence of brain metastases, and trastuzumab emtansine (T-DM1) is often employed. Stereotactic radiosurgery (SRS) is frequently utilized, and case series report increased toxicity with combination SRS and T-DM1. We provide an update of our experience of T-DM1 and SRS evaluating risk of clinically significant radionecrosis (CSRN) and propose a mechanism for this toxicity.

EXPERIMENTAL DESIGN

Patients with breast cancer who were ≤45 years regardless of HER2 status or had HER2⁺ disease regardless of age and underwent SRS for brain metastases were included. Rates of CSRN, SRS data, and details of T-DM1 administration were recorded. Proliferation and astrocytic swelling studies were performed to elucidate mechanisms of toxicity.

RESULTS

A total of 45 patients were identified; 66.7% were HER2⁺, and 60.0% were ≤ 45 years old. Of the entire cohort, 10 patients (22.2%) developed CSRN, 9 of whom received T-DM1. CSRN was observed in 39.1% of patients who received T-DM1 versus 4.5% of patients who did not. Receipt of T-DM1 was associated with a 13.5-fold (P = 0.02) increase in CSRN. Mechanistically, T-DM1 targeted reactive astrocytes and increased radiation-induced cytotoxicity and astrocytic swelling via upregulation of Aquaporin-4 (Aqp4).

CONCLUSIONS

The strong correlation between development of CSRN after SRS and T-DM1 warrants prospective studies controlling for variations in timing of T-DM1 and radiation dosing to further stratify risk of CSRN and mitigate toxicity. Until such studies are completed, we advise caution in the combination of SRS and T-DM1.

Strategies to Preserve Cognition in Patients With Brain Metastases: A Review

Brain metastases are common to the natural history of many advanced malignancies. Historically, whole brain radiation therapy (WBRT) has played a key role in the management of brain metastases, especially for patients with multiple lesions. However, prospective trials have demonstrated consistent neurocognitive toxicities after WBRT, and various pharmacologic and anatomic strategies designed to mitigate these toxicities have been studied in recent years. Memantine, an NMDA receptor antagonist, taken during and after WBRT improved cognitive preservation in a randomized trial over placebo. Deliberate reductions in radiation dose to the hippocampus, via hippocampal-avoidance (HA)-WBRT, resulted in improved cognition over historic controls in a phase II trial, and follow-up randomized trials are now ongoing to evaluate cognitive outcomes with HA vs. conventional brain radiation techniques. Nevertheless, some of the most promising strategies currently available to reduce the cognitive effects of brain radiation may be found in efforts to avoid or delay WBRT administration altogether. Stereotactic radiosurgery (SRS), involving focused, high-dose radiation to central nervous system (CNS) lesions with maximal sparing of normal brain parenchyma, has become the standard for limited brain metastases (classically 1–3 or 4 lesions) in the wake of multiple randomized trials demonstrating equivalent survival and improved cognition with SRS alone compared to SRS plus WBRT. Today, there is growing evidence to support SRS alone for multiple (≥4) brain metastases, with comparable survival to SRS alone in patients with fewer lesions. In patients with small-cell lung cancer, the routine use of prophylactic cranial irradiation (PCI) for extensive-stage disease has been also been challenged following the results of a randomized trial supporting an alternative strategy of MRI brain surveillance and early salvage radiation for the development of brain metastases. Moreover, new systemic agents are demonstrating increasing CNS penetration and activity, with the potential to offer greater control of widespread and microscopic brain disease that was previously only achievable with WBRT. In this review, we endeavor to put these clinical data on cognition and brain metastases into historical context and to survey the evolving landscape of strategies to improve future outcomes.

Disparities Predict for Higher Rates of Cut-through Hysterectomies in Locally Advanced Cervical Cancer

OBJECTIVES

The treatment of choice for locally advanced cervical cancer is definitive chemoradiation (CRT). Hysterectomy is not indicated due to higher-rates of cut-through resections leaving gross disease behind, requiring additional therapy with increasing morbidity and no benefit in overall survival (OS). The objectives of this study were to determine factors associated with cut-through hysterectomies and evaluate OS outcomes.

MATERIALS AND METHODS

The National Cancer Database (NCDB) was queried for patients 18 years and older with clinical Federation of Gynecology and Obstetrics stage IB2 to IVA. All patients underwent upfront hysterectomy and had known margin status. Cut-through hysterectomy was classified as presence of microscopic or macroscopic disease at the margin.

RESULTS

A total of 11,638 patients were included; 993 (8.5%) had positive margins. In patients with positive margins, 560 (56.4%) received postoperative CRT and 148 (14.9%) underwent postoperative radiation. Five-year OS was worse for those with cut-through resections when compared with those with negative margins, 66.0% versus 86.7%, respectively (hazard ratios, 3.08; P<0.001). Under multiple logistic regression, African American race (odds ratio [OR], 1.45; P=0.001), older age (OR per year increase, 1.03; P<0.001), patients with government insurance (OR, 1.21; P=0.019), and those treated at community practices (OR, 1.31; P=0.001) were more likely to undergo cut-through hysterectomies.

CONCLUSIONS

A review of national patterns of care over the past decade confirms women with positive margins after hysterectomy for cervical cancer have significantly worse OS. Disparities in surgical results for women with cervical cancer exist. In response, further causality evaluation and corrective action are warranted to address these inequalities.

Radiation therapy in the management of pancreatic adenocarcinoma: review of current evidence and future opportunities

The role of radiation therapy for pancreatic cancer is rapidly evolving in every stage of this disease. In resectable disease, there is conflicting evidence for adjuvant therapy, but an ongoing randomized cooperative group trial is attempting to define the role of adjuvant chemoradiation with modern systemic therapies and radiation techniques with an emphasis on radiation quality assurance. In borderline resectable pancreatic cancer (BRPC), there is an emerging body of literature demonstrating the success of neoadjuvant stereotactic body radiation therapy (SBRT) and a randomized cooperative group trial is actively accruing. For locally advanced pancreatic cancer (LAPC), the recent publication of the LAP07 trial has called into question the role of conventional chemoradiation, but there is a growing experience utilizing SBRT for this patient group. Finally, in the era of immuno-oncology, there may be a new role for radiation therapy in combination with systemic immune therapy to stimulate antigen release and abscopal responses, thus benefitting even patients with metastatic pancreatic cancer.

Radiosurgery alone is associated with favorable outcomes for brain metastases from small-cell lung cancer

INTRODUCTION

Whole-brain radiation therapy (WBRT) is the standard approach for brain metastases (BM) arising in patients with small-cell lung cancer (SCLC), but the neurocognitive toxicities of WBRT are well documented. For this reason, stereotactic radiosurgery (SRS) alone is the preferred modality for limited BM in most histologies, but in SCLC there are few data exploring this approach.

METHODS

We queried the National Cancer Database (NCDB) for patients with SCLC with BM at diagnosis and stratified by upfront SRS compared with upfront WBRT ± SRS. We utilized multivariate Cox regression and propensity score matching (PSM) to determine the impact on overall survival (OS) of each approach.

RESULTS

5952 eligible patients (WBRT: 5752; SRS: 200) were identified from 2010 to 2014 with a median follow-up of 40.0 months. Upfront SRS was associated with superior OS (median 10.8 vs 7.1 months, HR 0.65, 95% CI 0.55-0.75, p < 0.001), which persisted on multivariate analysis controlling for comorbidities, extracranial metastases, age, race/ethnicity, and gender (HR 0.70, 95% CI 0.60-0.81, p < 0.001). These results were confirmed in PSM analysis. A subset analysis comparing outcomes after SRS vs SRS + WBRT showed no differences in OS (p = .601).

CONCLUSIONS

To our knowledge, this is the largest dataset of patients treated with SRS alone for SCLC. The observation of favorable OS with SRS alone in this contemporary dataset suggests that SRS alone may be appropriate for some patients with SCLC. Prospective investigations of SRS in SCLC are warranted.

Physician Bias in Prophylactic Cranial Irradiation Decision Making-An Opportunity for a Patient Decision Aid

INTRODUCTION

Guidelines have recommended prophylactic cranial irradiation (PCI) for patients with limited-stage small-cell lung cancer with at least a partial response after thoracic chemoradiation. However, the survival advantage has been small and was observed in an era before magnetic resonance imaging and surveillance. Neurotoxicity also remains a concern, especially in older adults. Thus, patients have a complex value-laden decision to make. We sought to better understand the role physicians play in patient decision making and introduce a patient decision aid (PDA) to potentially facilitate these discussions.

MATERIALS AND METHODS

An e-mail survey was sent to International Association for the Study of Lung Cancer members querying their personal perspectives and professional recommendations regarding PCI for limited-stage small-cell lung cancer.

RESULTS

We received 295 responses. Most were from the United States (35%) and Europe (35%) and were radiation (45%) or medical (43%) oncologists. Of those responding, 88% and 50% reported they would recommend PCI to a 50- and 70-year-old patient, respectively. Also, 79% reported that they would wish to receive PCI if faced with this decision. The physicians who would have chosen PCI if faced with the decision were 27.6 and 12.9 times more likely to recommend PCI to a 50- and 70-year-old patient, respectively, than were physicians who would not undergo PCI themselves. Most of the respondents had positive responses to the proposed PDA.

CONCLUSION

Physician bias appears to play a role in PCI counseling, and most physicians reported that the provided PDA was better than their present method for discussing PCI and would help patients make such value-laden choices.

A comprehensive comparative analysis of treatment modalities for sinonasal malignancies

BACKGROUND

Sinonasal malignancies are a rare and heterogeneous group of tumors for which there is a paucity of robust data with which to guide management decisions. The authors used the National Cancer Data Base to better understand the presenting characteristics of these tumors and to compare outcomes by treatment modality.

METHODS

The National Cancer Data Base was queried for sinonasal malignancies diagnosed between 2004 and 2012. Overall survival was assessed using multivariate analyses and propensity score matching.

RESULTS

A total of 11,160 patients were identified for the initial analysis. The majority were male, aged 40 to 69 years, with tumors of the nasal cavity or maxillary sinus. Squamous cell histology was most common. The majority of patients presented with advanced tumor stage but without locoregional lymph node or distant metastases. Treatment modalities were compared for squamous cell carcinomas. In multivariate analysis, compared with surgery alone, patients who received adjuvant radiotherapy (hazard ratio [HR], 0.658 [P<.001]), adjuvant chemoradiotherapy (HR, 0.696 [P = .002]), or neoadjuvant therapy (HR, 0.656 [P = .007]) had improved overall survival. Patients who received radiotherapy alone (HR, 1.294 [P = .001]) or chemotherapy alone (HR, 1.834 [P<.001]) had worse outcomes. These findings were validated in propensity score matching. It is important to note that neoadjuvant chemoradiotherapy was associated with achieving a negative surgical margin (odds ratio, 2.641 [P = .045]).

CONCLUSIONS

Surgery is the mainstay of therapy for patients with sinonasal malignancies, but multimodality therapy is associated with improved overall survival. Cancer 2017;123:3040-49. © 2017 American Cancer Society.

The Impact of Postoperative Radiotherapy for Thymoma and Thymic Carcinoma

INTRODUCTION

The optimal role for postoperative radiotherapy (PORT) for thymoma and thymic carcinoma remains controversial. We used the National Cancer Data Base to investigate the impact of PORT on overall survival (OS).

METHODS

Patients who underwent an operation for thymoma or thymic carcinoma were categorized into Masaoka-Koga stage groups I to IIA, IIB, III, and IV. Patients who did not undergo an operation or those who received preoperative radiation were excluded. Kaplan-Meier estimates of OS and univariate and multivariate Cox proportional hazards regression analyses were performed. Propensity score-matched analyses were performed to further control for baseline confounders.

RESULTS

From 2004 to 2012, 4056 patients were eligible for inclusion, 2001 of whom (49%) received PORT. On multivariate analysis of OS in the thymoma cohort adjusted for age, WHO histologic subtype, Masaoka-Koga stage group, surgical margins, and chemotherapy administration, PORT was associated with superior OS (hazard ratio [HR] = 0.72, p = 0.001). Propensity score-matched analyses confirmed the survival advantage associated with PORT. Subset analysis indicated longer OS in association with PORT for patients with stage IIB thymoma (HR = 0.61, p = 0.035), stage III (HR = 0.69, p = 0.020), and positive margins (HR = 0.53, p < 0.001). The impact of PORT for stage I to IIA disease did not reach significance (HR = 0.76, p = 0.156).

CONCLUSIONS

In this large database analysis of PORT for thymic tumors, PORT was associated with longer OS, with the greatest relative benefits observed for stage IIB to III disease and positive margins. In the absence of randomized studies assessing the value of PORT, these data may inform clinical practice.

Predictors of overall survival in human papillomavirus-associated oropharyngeal cancer using the National Cancer Data Base

OBJECTIVES

This study identifies clinical characteristics associated with HPV-positive oropharynx squamous cell carcinoma (OPSCC) and evaluates predictors of overall survival (OS) in HPV-positive patients undergoing definitive treatment within the National Cancer Data Base (NCDB).

MATERIAL AND METHODS

The NCDB was queried for patients ⩾18years old with OPSCC and known HPV status who underwent definitive treatment: surgery, radiation (RT), chemotherapy-RT (CRT), surgery+RT, surgery+CRT (S-CRT). Cox proportional hazards model was used for multivariate analysis (MVA) to evaluate predictors of OS by HPV status.

RESULTS

3952 patients were included: 2454 (62%) were HPV-positive. Median follow up was 23.7months (range, 1.0-54.5). Unadjusted 2-year OS rates for HPV-positive vs. negative were 93.1% vs. 77.8% (p<0.001) with an adjusted hazard ratio of 0.44 (95% CI, 0.36-0.53; p<0.001). MVA identified multimodality treatment including CRT (HR, 0.42; p=0.024) and S-RT (HR, 0.30; p=0.024), but not S-CRT (HR, 0.51; p=0.086), as predictors for improved OS in HPV-positive stage III-IVB disease. Multimodality treatment including S-CRT was associated with longer OS in HPV-negative OPSCC. Nodal stage was poorly associated with OS in HPV-positive cancers. The presence of positive margins and/or extracapsular extension was associated with worse OS in HPV-negative (HR, 2.11; p=0.008) but not HPV positive OPSCC (HR, 1.61; p=0.154).

CONCLUSION

The established demographic and clinical features of HPV-positive OPSCC were corroborated in the NCDB. Population analysis suggests that AJCC staging is poorly associated with OS in HPV-positive cancer, and traditional high-risk features may be less impactful. Bimodality therapy appears beneficial in HPV-positive HNSCC.

Safety of contralateral submandibular gland sparing in locally advanced oropharyngeal cancers: A multicenter review

BACKGROUND

Previous groups have shown contralateral submandibular gland sparing to improve xerostomia with safe outcomes, but primarily in early-stage disease. In this study, we present a large cohort of patients with locally advanced head and neck cancer that underwent contralateral submandibular gland-sparing radiotherapy, to demonstrate feasibility and safety specifically in patients with locally advanced disease.

METHODS

We retrospectively analyzed patients who were treated prospectively with contralateral submandibular gland sparing. Only patients who underwent bilateral neck radiotherapy with contralateral submandibular gland doses <39 Gy were included.

RESULTS

We identified 71 patients. Approximately 80% of patients had ≥N2b disease. The contralateral submandibular gland mean dose was 33 Gy and, at a median follow-up of 27.3 months, no patients experienced treatment failure in the contralateral level IB lymph nodes.

CONCLUSION

Xerostomia remains a significant morbidity despite parotid sparing and can be minimized further by contralateral submandibular gland sparing. These data provide important preliminary evidence that contralateral submandibular gland sparing is feasible and may be safe even in locally advanced cancers.

Allosteric inhibitors of the Eya2 phosphatase are selective and inhibit Eya2-mediated cell migration

Eya proteins are essential co-activators of the Six family of transcription factors and contain a unique tyrosine phosphatase domain belonging to the haloacid dehalogenase family of phosphatases. The phosphatase activity of Eya is important for the transcription of a subset of Six1-target genes, and also directs cells to the repair rather than apoptosis pathway upon DNA damage. Furthermore, Eya phosphatase activity has been shown to mediate transformation, invasion, migration, and metastasis of breast cancer cells, making it a potential new drug target for breast cancer. We have previously identified a class of N-arylidenebenzohydrazide compounds that specifically inhibit the Eya2 phosphatase. Herein, we demonstrate that these compounds are reversible inhibitors that selectively inhibit the phosphatase activity of Eya2, but not Eya3. Our mutagenesis results suggest that this class of compounds does not bind to the active site and the binding does not require the coordination with Mg(2+). Moreover, these compounds likely bind within a site on the opposite face of the active site, and function as allosteric inhibitors. We also demonstrate that this class of compounds inhibits Eya2 phosphatase-mediated cell migration, setting the foundation for these molecules to be developed into chemical probes for understanding the specific function of the Eya2 phosphatase and to serve as a prototype for the development of Eya2 phosphatase specific anti-cancer drugs.

EWS/FLI1 regulates EYA3 in Ewing sarcoma via modulation of miRNA-708, resulting in increased cell survival and chemoresistance

Ewing sarcoma is an aggressive pediatric cancer of the bone and soft tissue, in which patients whose tumors have a poor histologic response to initial chemotherapy have a poor overall prognosis. Therefore, it is important to identify molecules involved in resistance to chemotherapy. Herein, we show that the DNA repair protein and transcriptional cofactor, EYA3, is highly expressed in Ewing sarcoma tumor samples and cell lines compared with mesenchymal stem cells, the presumed cell-of-origin of Ewing sarcoma, and that it is regulated by the EWS/FLI1 fusion protein transcription factor. We further show that EWS/FLI1 mediates upregulation of EYA3 via repression of miR-708, a miRNA that targets the EYA3 3'-untranslated region, rather than by binding the EYA3 promoter directly. Importantly, we show that high levels of EYA3 significantly correlate with low levels of miR-708 in Ewing sarcoma samples, suggesting that this miR-mediated mechanism of EYA3 regulation holds true in human cancers. Because EYA proteins are important for cell survival during development, we examine, and show, that loss of EYA3 decreases survival of Ewing sarcoma cells. Most importantly, knockdown of EYA3 in Ewing sarcoma cells leads to sensitization to DNA-damaging chemotherapeutics used in the treatment of Ewing sarcoma, and as expected, after chemotherapeutic treatment, EYA3 knockdown cells repair DNA damage less effectively than their control counterparts. These studies identify EYA3 as a novel mediator of chemoresistance in Ewing sarcoma and define the molecular mechanisms of both EYA3 overexpression and of EYA3-mediated chemoresistance.

Molecular pathways: targeting the TGF-β pathway for cancer therapy

TGF-β is a ubiquitous cytokine that plays an active role in many cellular processes. Nearly every cell type has the ability to secrete TGF-β, as well as the ability to respond to TGF-β via the presence of TGF-β receptors on the cell surface. Consequently, gain or loss of function of the TGF-β pathway and its components are known to lead to a variety of diseases, including cancer. In epithelial cells, TGF-β functions as a tumor suppressor, where it inhibits proliferation, induces apoptosis, and mediates differentiation. Conversely, in other contexts, TGF-β promotes tumor progression through increasing tumor cell invasion and metastasis. Thus, TGF-β can have opposing roles, likely dependent, in part, on whether the cancer is early or late stage. The effects of TGF-β on tumor suppression and promotion are not limited to the tumor cell itself; rather, these effects can also be mediated through the stroma and the immune system. The dichotomous role of TGF-β in cancer highlights our need to understand the contextual effects of this cytokine to better guide patient selection for the use of anti-TGF-β therapies currently in clinical trials.

Abstract B78: A novel EWS/Fli1 target gene, Eya3, is upregulated in Ewing's sarcoma to mediate chemoresistance

Ewing's sarcoma is an aggressive pediatric cancer of the bone and soft tissue, in which patients' whose tumors have a poor histological response to initial chemotherapy have a poor overall prognosis. Importantly, childhood cancer survivors are faced with long-term chemotherapy-associated toxicities many years after they have been cured of their primary disease. Therefore, targeting molecules involved in resistance to chemotherapy should benefit patients with resistant disease and allow lower doses of toxic chemotherapies to be used in treatment regimens, thus improving outcomes for children suffering from Ewing's sarcoma on multiple fronts. The vast majority of Ewing's sarcomas harbor a characteristic translocation, t(11;22), encoding the EWS/Fli1 fusion protein. We have identified the DNA-repair protein and transcriptional cofactor, Eya3, as a downstream target of EWS/Fli1. Eya3 is highly expressed in Ewing's sarcoma tumor samples and cell lines compared with mesenchymal stem cells, the presumed cell of origin of Ewing's sarcoma. We demonstrate that EWS/Fli1 mediates upregulation of Eya3 via repression of miR-145 and miR-708, microRNAs that target the Eya3 3'UTR. Furthermore, replacement of miR-145 and miR-708 in a Ewing's sarcoma cell line decreases Eya3 levels. It was recently shown that Eya3 promotes DNA repair by dephosphorylating a critical tyrosine residue on H2AX in response to DNA damage, resulting in the recruitment of DNA repair factors to the sites of DNA damage. Thus we tested whether knockdown of Eya3 in Ewing's sarcoma cells would decrease cell survival and sensitize cells to DNA-damaging chemotherapeutics used in the treatment of Ewing's sarcoma: etoposide and doxorubicin. Indeed, Eya3 knockdown led to increased cell death and sensitization to chemotherapy, and, as expected, Eya3 knockdown cells contained more DNA damage following treatment with etoposide than their control counterparts. These data strongly suggest that Eya3 mediates chemoresistance in Ewing's sarcoma through its ability to enhance DNA repair. Because Eya3 mediates DNA repair and survival via its intrinsic phosphatase activity, and because the phosphatase activity of Eya is also known to play a role in metastasis of other cancers, we have begun to develop inhibitors targeting the Eya phosphatase activity and to demonstrate their efficacy both in vitro and in cell culture. In closing, Eya phosphatase inhibitors or synthetic mimics of the microRNAs targeting Eya3 have the potential to improve outcomes for Ewing's sarcoma patients by improving therapeutic efficacy and decreasing associated toxicities of conventional chemotherapeutics.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B78.

On the mechanisms of 12-O-tetradecanoylphorbol-13-acetate-induced growth arrest in pancreatic cancer cells

OBJECTIVES

Protein kinase C (PKC) is involved in cell growth, differentiation, and apoptosis. We investigated the effects of the PKC activator, the tetradecanylphorbol acetate (TPA), in human pancreatic cancer cells.

METHODS

Cell proliferation was measured by thymidine incorporation. Expression of cell cycle proteins was investigated by Western blot. Real-time reverse transcriptase-polymerase chain reaction was used to measure p21 messenger RNA expression, whereas knockdown of its expression was accomplished with a specific small interferring RNA. Cell cycle phases were determined by flow cytometry.

RESULTS

TPA time and concentration dependently inhibited thymidine incorporation in Panc-1 and CD18 cells and induced G2/M cell cycle arrest. The TPA decreased cyclin A and B expression, increased cyclin E, and markedly increased the expression of p21 at both the messenger RNA and protein levels. TPA-induced p21 expression and growth inhibition were blocked by the PKC inhibitor, bisindoylmaleimide. TPA induced extracellular signal-regulated kinase1/2 phosphorylation, whereas the MEK inhibitor, PD98059, blocked the TPA-induced p21 expression. Small interferring RNA targeted to p21 blocked TPA-induced p21 protein expression but not TPA-induced cell growth arrest.

CONCLUSIONS

TPA-induced p21 expression is mediated by the MEK/ERK pathway but is not involved in TPA-induced growth inhibition. In contrast, cyclin A and cyclin B are likely involved in TPA-induced G2/M arrest because both proteins are involved in S phase and G2/M transition during cell proliferation.