Real-World Use of Hypofractionated Radiotherapy for Primary CNS Tumors in the Elderly, and Implications on Medicare Spending

BACKGROUND

For elderly patients with high-grade gliomas, 3-week hypofractionated radiotherapy (HFRT) is noninferior to standard long-course radiotherapy (LCRT). We analyzed real-world utilization of HFRT with and without systemic therapy in Medicare beneficiaries treated with RT for primary central nervous system (CNS) tumors using Centers for Medicare & Medicaid Services data.

METHODS

Radiation modality, year, age (65-74, 75-84, or ≥85 years), and site of care (freestanding vs hospital-affiliated) were evaluated. Utilization of HFRT (11-20 fractions) versus LCRT (21-30 or 31-40 fractions) and systemic therapy was evaluated by multivariable logistic regression. Medicare spending over the 90-day episode after RT planning initiation was analyzed using multivariable linear regression.

RESULTS

From 2015 to 2019, a total of 10,702 RT courses (ie, episodes) were included (28% HFRT; 65% of patients aged 65-74 years). A considerable minority died within 90 days of RT planning initiation (n=1,251; 12%), and 765 (61%) of those received HFRT. HFRT utilization increased (24% in 2015 to 31% in 2019; odds ratio [OR], 1.2 per year; 95% CI, 1.1-1.2) and was associated with older age (≥85 vs 65-74 years; OR, 6.8; 95% CI, 5.5-8.4), death within 90 days of RT planning initiation (OR, 5.0; 95% CI, 4.4-5.8), hospital-affiliated sites (OR, 1.4; 95% CI, 1.3-1.6), conventional external-beam RT (vs intensity-modulated RT; OR, 2.7; 95% CI, 2.3-3.1), and no systemic therapy (OR, 1.2; 95% CI, 1.1-1.3; P<.001 for all). Increasing use of HFRT was concentrated in hospital-affiliated sites (P=.002 for interaction). Most patients (69%) received systemic therapy with no differences by site of care (P=.12). Systemic therapy utilization increased (67% in 2015 to 71% in 2019; OR, 1.1 per year; 95% CI, 1.0-1.1) and was less likely for older patients, patients who died within 90 days of RT planning initiation, those who received conventional external-beam RT, and those who received HFRT. HFRT significantly reduced spending compared with LCRT (adjusted β for LCRT = +$8,649; 95% CI, $8,544-$8,755), whereas spending modestly increased with systemic therapy (adjusted β for systemic therapy = +$270; 95% CI, $176-$365).

CONCLUSIONS

Although most Medicare beneficiaries received LCRT for primary brain tumors, HFRT utilization increased in hospital-affiliated centers. Despite high-level evidence for elderly patients, discrepancy in HFRT implementation by site of care persists. Further investigation is needed to understand why patients with short survival may still receive LCRT, because this has major quality-of-life and Medicare spending implications.

Prognostic Implications of Small Cell Lung Cancer Transcriptional Subtyping for CNS Metastases

PURPOSE

Small cell lung cancer (SCLC) often metastasizes to the brain and has poor prognosis. SCLC subtypes distinguished by expressing transcriptional factors ASCL1 or NEUROD1 have been identified. This study investigates the impact of transcription factor-defined SCLC subtype on incidence and outcomes of brain metastases (BMs).

METHODS

Patients with SCLC with ASCL1 (A) and NEUROD1 (N) immunohistochemical expression status were identified and classified: (1) A+/N-, (2) A+/N+, (3) A-/N+, and (4) A-/N-. Cumulative incidence competing risk analyses were used to assess incidence of CNS progression. Cox proportional hazards models were used for multivariable analyses of overall survival (OS) and CNS progression-free survival (CNS-PFS).

RESULTS

Of 164 patients, most were either A+/N- or A+/N+ (n = 62, n = 63, respectively). BMs were present at diagnosis in 24 patients (15%). Among them, the 12-month cumulative incidence of subsequent CNS progression was numerically highest for A+/N- (50% [95% CI, 10.5 to 74.7]; P = .47). Among those BM-free at diagnosis, the 12-month cumulative incidence of CNS progression was numerically the highest for A+/N- (16% [95% CI, 7.5 to 27.9]) and A-/N+ (9.1% [95% CI, 0.0 to 34.8]; P = .20). Both subtypes, A+/N- and A-/N+, had worse OS compared with A+/N+ (A+/N-: hazard ratio [HR], 1.62 [95% CI, 1.01 to 2.51]; P < .05; A-/N+: HR, 3.02 [95% CI, 1.35 to 6.76]; P = .007). Excellent response rates (28, 65% CR/PR) across subtypes were seen in patients who had CNS-directed radiotherapy versus systemic therapy alone (9, 36% CR/PR).

CONCLUSION

To our knowledge, this report is the first to investigate CNS-specific outcomes based on transcription factor subtypes in patients with SCLC. BM-free patients at diagnosis with A+/N- or A-/N+ subtypes had worse outcomes compared with those with transcriptional factor coexpression. Further investigation into the mechanisms and implications of SCLC subtyping on CNS-specific outcomes is warranted to ultimately guide personalized care.

40 Gray in 5 Fractions for Salvage Reirradiation of Spine Lesions Previously Treated With Stereotactic Body Radiotherapy

BACKGROUND AND PURPOSE

A retrospective single-center analysis of the safety and efficacy of reirradiation to 40 Gy in 5 fractions (reSBRT) in patients previously treated with stereotactic body radiotherapy to the spine was performed.

METHODS

We identified 102 consecutive patients treated with reSBRT for 105 lesions between 3/2013 and 8/2021. Sixty-three patients (61.8%) were treated to the same vertebral level, and 39 (38.2%) to overlapping immediately adjacent levels. Local control was defined as the absence of progression within the treated target volume. The probability of local progression was estimated using a cumulative incidence curve. Death without local progression was considered a competing risk.

RESULTS

Most patients had extensive metastatic disease (54.9%) and were treated to the thoracic spine (53.8%). The most common regimen in the first course of stereotactic body radiotherapy was 27 Gy in 3 fractions, and the median time to reSBRT was 16.4 months. At the time of simulation, 44% of lesions had advanced epidural disease. Accordingly, 80% had myelogram simulations. Both the vertebral body and posterior elements were treated in 86% of lesions. At a median follow-up time of 13.2 months, local failure occurred in 10 lesions (9.5%). The 6- and 12-month cumulative incidences of local failure were 4.8% and 6%, respectively. Seven patients developed radiation-related neuropathy, and 1 patient developed myelopathy. The vertebral compression fracture rate was 16.7%.

CONCLUSION

In patients with extensive disease involvement, reSBRT of spine metastases with 40 Gy in 5 fractions seems to be safe and effective. Prospective trials are needed to determine the optimal dose and fractionation in this clinical scenario.

Artificial-intelligence-driven measurements of brain metastases' response to SRS compare favorably with current manual standards of assessment

Background

Evaluation of treatment response for brain metastases (BMs) following stereotactic radiosurgery (SRS) becomes complex as the number of treated BMs increases. This study uses artificial intelligence (AI) to track BMs after SRS and validates its output compared with manual measurements.

Methods

Patients with BMs who received at least one course of SRS and followed up with MRI scans were retrospectively identified. A tool for automated detection, segmentation, and tracking of intracranial metastases on longitudinal imaging, MEtastasis Tracking with Repeated Observations (METRO), was applied to the dataset. The longest three-dimensional (3D) diameter identified with METRO was compared with manual measurements of maximum axial BM diameter, and their correlation was analyzed. Change in size of the measured BM identified with METRO after SRS treatment was used to classify BMs as responding, or not responding, to treatment, and its accuracy was determined relative to manual measurements.

Results

From 71 patients, 176 BMs were identified and measured with METRO and manual methods. Based on a one-to-one correlation analysis, the correlation coefficient was R2 = 0.76 (P = .0001). Using modified BM response classifications of BM change in size, the longest 3D diameter data identified with METRO had a sensitivity of 0.72 and a specificity of 0.95 in identifying lesions that responded to SRS, when using manual axial diameter measurements as the ground truth.

Conclusions

Using AI to automatically measure and track BM volumes following SRS treatment, this study showed a strong correlation between AI-driven measurements and the current clinically used method: manual axial diameter measurements.

Symptomatic Necrosis With Antibody-Drug Conjugates and Concurrent Stereotactic Radiotherapy for Brain Metastases

This cohort study investigates whether brain metastases that manifest after stereotactic radiotherapy with concurrent antibody-drug conjugates are associated with an increased risk of symptomatic radiation necrosis.

Outcomes Following Early Postoperative Adjuvant Radiosurgery for Brain Metastases

Importance

Adjuvant stereotactic radiosurgery (SRS) enhances the local control of resected brain metastases (BrM). However, the risks of local failure (LF) and potential for posttreatment adverse radiation effects (PTRE) after early postoperative adjuvant SRS have not yet been established.

Objective

To evaluate whether adjuvant SRS delivered within a median of 14 days after surgery is associated with improved LF without a concomitant increase in PTRE.

Design, Setting, and Participants

This prospective cohort study examines a clinical workflow (RapidRT) that was implemented from 2019 to 2022 to deliver SRS to surgical patients within a median of 14 days, ensuring all patients were treated within 30 days postoperatively. This prospective cohort was compared with a historical cohort (StanRT) of patients with BrM resected between 2013 and 2019 to assess the association of the RapidRT workflow with LF and PTRE. The 2 cohorts were combined to identify optimal SRS timing, with a median follow-up of 3.3 years for survivors.

Exposure

Timing of adjuvant SRS (14, 21, and 30 days postoperatively).

Main Outcomes and Measures

LF and PTRE, according to modified Response Assessment in Neuro-Oncology Brain Metastases criteria.

Results

There were 438 patients (265 [60.5%] female patients; 23 [5.3%] Asian, 27 [6.2%] Black, and 364 [83.1%] White patients) with a mean (SD) age of 62 (13) years; 377 were in the StanRT cohort and 61 in the RapidRT cohort. LF and PTRE rates at 1 year were not significantly different between RapidRT and StanRT cohorts. Timing of SRS was associated with radiographic PTRE. Patients receiving radiation within 14 days had the highest 1-year PTRE rate (18.08%; 95% CI, 8.31%-30.86%), and patients receiving radiation between 22 and 30 days had the lowest 1-year PTRE rate (4.10%; 95% CI, 1.52%-8.73%; P = .03). LF rates were highest for patients receiving radiation more than 30 days from surgery (10.65%; 95% CI, 6.90%-15.32%) but comparable for patients receiving radiation within 14 days, between 15 and 21 days, and between 22 and 30 days (≤14 days: 5.12%; 95% CI, 0.86%-15.60%; 15 to ≤21 days: 3.21%; 95% CI, 0.59%-9.99%; 22 to ≤30 days: 6.58%; 95% CI, 3.06%-11.94%; P = .20).

Conclusions and Relevance

In this cohort study of adjuvant SRS timing following surgical resection of BrM, the optimal timing for adjuvant SRS appears to be within 22 to 30 days following surgery. The findings of this study suggest that this timing allows for a balanced approach that minimizes the risks associated with LF and PTRE.

The Impact of Co-Alterations on Outcomes after Local Therapy for Patients with KRAS-Mutant Lung Adenocarcinoma Brain Metastases

PURPOSE/OBJECTIVE(S)

Brain metastases are common in NSCLC with up to 25% of patients having brain metastases (BMs) at the time of diagnosis and 30% developing BMs during their disease course. KRAS is an oncogenic driver in approximately 25% of lung adenocarcinomas. Genomic alterations co-occurring with KRAS are associated with distinct biological landscapes which may influence prognosis. Herein, we sought to identify correlations between genomic profiles, intracranial progression free survival (iPFS), and overall survival (OS).

MATERIALS/METHODS

We retrospectively reviewed 156 patients with KRAS-mutant lung adenocarcinoma BM who underwent SRS for their BMs at MSKCC from 2010-2022. Each patient had at least one tumor sample profiled with MSK-IMPACT, a custom FDA-cleared next-generation sequencing. Mutations, copy number alterations, and fusions were filtered for driver alterations using OncoKB. Survival outcomes were calculated from date of MRI indicating metastatic brain disease.

RESULTS

Of the 156 patients, 80 patients presented with BMs at diagnosis whereas 76 developed BMs during their disease course, with a median 2 lines of therapy prior to BM diagnosis. The most common KRAS mutation was G12C (n = 64; 41%), G12V (n = 26, 17%), G12D (n = 17; 11%), and G12A (n = 11; 7%). The most frequently co-altered genes were TP53 (n = 71, 46%), STK11 (n = 51, 33%), CDKN2A (n = 27, 17%), KEAP1 (n = 17, 11%), and SMARCA4 (n = 10, 6%). The presence of a KEAP1 co-occurring alteration was associated with inferior iPFS (HR 1.95, 95% CI 1.05 - 3.59, p = 0.035) and the presence of SMARCA4 was also associated with inferior iPFS (HR 2.28, 95% CI 1.05 - 4.95, p = 0.038). The presence of an STK11 mutation was associated with worse OS (HR 1.57, 95% 1.01 - 2.43, p = 0.045). In a multi-variate clinico-genomic model, KEAP1 and STK11 co-occurring alterations remained significantly associated with iPFS. Patients with KEAP1-altered tumors had an increased incidence of intracranial regional progression. The 24-month cumulative incidence of regional progression amongst KEAP1-altered tumors was 57% (95% CI, 29%-77%) compared with 37% (95% CI, 29%-46%) among KEAP1-wildtype tumors (P = 0.041). Patients with CDKN2A-altered tumors had an increased incidence of leptomeningeal disease (LMD) as a form of intracranial progression. The 24-month cumulative incidence of LMD amongst CDKN2A-altered tumors was 11% (95% CI, 2.7%-27%) compared with 4.1% (95% CI, 1.5%-8.8%) among CDKN2A-wildtype tumors (P = 0.023).

CONCLUSION

In our cohort of molecularly profiled KRAS-mutant lung adenocarcinoma BM patients treated with SRS, we found that co-occurring KEAP1 and STK11 were significantly associated with worse iPFS. We also observed that CDKN2A co-altered tumors had an increased incidence of LMD. These findings have implications for future efforts to personalize brain metastasis management based on comprehensive genomic profiling.

Salvage Radiotherapy as a Bridge for Relapsed Secondary CNS Lymphoma

PURPOSE/OBJECTIVE(S)

Secondary CNS lymphoma (SCNSL) is a challenging clinical scenario observed in 2-5% of non-Hodgkin lymphoma patients, for which a standard of care has not been defined. We studied the indications for, and outcomes of SCNSL patients referred for radiotherapy (RT).

MATERIALS/METHODS

We identified patients with aggressive B cell lymphoma who received brain RT for SCNSL between 1999-2023 at a tertiary cancer center. Patients were grouped and analyzed by RT indication. Overall survival (OS) was determined from RT start using the Kaplan-Meier method. OS analysis comparing patients who did and did not receive therapy after RT was landmarked at 60 days from start of RT to minimize immortal time bias. "SCNSL-directed therapy" is defined as systemic therapy for the treatment of SCNSL, as opposed to CNS prophylaxis.

RESULTS

We identified 99 SCNSL patients treated with RT. To account for the heterogeneity of RT referrals, we focused on the most common indication: salvage of radiographic progression after SCNSL-directed systemic therapy (n = 58). Among this group, median age was 62 (interquartile range [IQR]: 48-69) and 86% had diffuse large B cell histology. At initial lymphoma diagnosis, 10% of patients had CNS involvement, 90% received Rituximab-based therapy, and 25% received prior CNS prophylaxis. For SCNSL directed therapy, 90% received methotrexate (MTX)-based regimen. Median time from initial SCNSL diagnosis to RT was 4.4 months (IQR 1.7-7.0), with a median of 2.0 lines of therapy prior to RT (IQR 1.0-3.0). 86% of patients were symptomatic at RT with median KPS of 70 (IQR: 60-80). RT targets included whole brain (86%) and partial brain (14%). 1 patient had craniospinal RT. Median RT dose was 30 Gy (IQR: 24-30) over 10 fractions. Median OS for the entire salvage cohort was 3.5 months (m). Landmark analysis 2m post RT showed that median OS differed when patients were stratified by receipt of further therapy: CAR-T (9.4m, n = 4), hematopoietic cell transplant (8.5m, n = 6), other systemic therapy (4.4m, n = 17), no systemic therapy (0.6m, n = 10) (p = 0.0004). 29% of patients who received further therapy after RT achieved long term survival.

CONCLUSION

In our cohort, most SCNSL patients are referred for salvage RT, with a median OS of 3.5m. 86% of patients had neurologic symptoms after having failed a median of 2 lines of SCNSL-directed therapy; the clinical urgency of this scenario implies that without RT, patients may not have been suitable candidates for further therapy. However, among patients for whom RT was successfully used to bridge to additional therapy, 29% could achieve long-term survival. This study supports further investigation of RT as a combined modality strategy for relapsed/refractory SCNSL, including with emerging cellular therapies.

Genomic analysis and clinical correlations of non-small cell lung cancer brain metastasis

Up to 50% of patients with non-small cell lung cancer (NSCLC) develop brain metastasis (BM), yet the study of BM genomics has been limited by tissue access, incomplete clinical data, and a lack of comparison with paired extracranial specimens. Here we report a cohort of 233 patients with resected and sequenced (MSK-IMPACT) NSCLC BM and comprehensive clinical data. With matched samples (47 primary tumor, 42 extracranial metastatic), we show CDKN2A/B deletions and cell cycle pathway alterations to be enriched in the BM samples. Meaningful clinico-genomic correlations are noted, namely EGFR alterations in leptomeningeal disease (LMD) and MYC amplifications in multifocal regional brain progression. Patients who developed early LMD frequently have had uncommon, multiple, and persistently detectable EGFR driver mutations. The distinct mutational patterns identified in BM specimens compared to other tissue sites suggest specific biologic underpinnings of intracranial progression.

Characterization of Central Nervous System Clinico-Genomic Outcomes in ALK-Positive Non-Small Cell Lung Cancer Patients with Brain Metastases Treated with Alectinib

INTRODUCTION

Highly effective brain-penetrant ALK-targeted tyrosine kinase inhibitors (TKIs) have been developed for the management of NSCLC patients with brain metastases (BM). Local therapy (LT) such as SRS or therapeutic craniotomy is increasingly being deferred for such patients. Herein we report detailed patient- and lesion-level intracranial outcomes and co-mutational genomic profiles from a cohort of NSCLC patients with BM treated with alectinib, with or without LT.

METHODS

We retrospectively reviewed ALK fusion-positive NSCLC patients with BMs who received alectinib at the diagnosis of BM from 1/2012 and 5/2021. Outcome variables included intracranial progression-free survival (iPFS), overall survival (OS), duration of TKI therapy, and CNS response rates. Genomic characteristics from tumor specimens were assessed with MSK-IMPACT, a next-generation sequencing (NGS)-based genomic profiling assay.

RESULTS

A total of 38 patients with 114 CNS lesions were included. Twelve of these patients also received contemporaneous LT (SRS, WBRT, or surgical resection). Maximal BM diameter in the TKI + LT group was greater (p < 0.003) but despite this difference, iPFS (TKI only, HR 1.21, 95 % CI 0.51-2.89; p = 0.66) and OS (TKI only, HR 5.99, 95 % CI 0.77-46.6; p = 0.052) were similar between groups and trended towards more favorable outcomes with the addition of LT. SMARCA4 co-alterations were associated with inferior OS (HR 8.76, 1.74-44.2; p = 0.009).

CONCLUSIONS

Our study demonstrated that patients with ALK fusion-positive NSCLC treated with TKI + LT had larger BM and higher likelihood of pre-treatment neurologic symptoms. Despite these differences, iPFS was similar between groups. Results should be interpreted with caution as our study was limited by an underpowered sample size. SMARCA4 co-alterations were associated with inferior OS and these findings warrant further investigation.

Fractionated Proton Radiation Therapy and Hearing Preservation for Vestibular Schwannoma: Preliminary Analysis of a Prospective Phase 2 Clinical Trial

BACKGROUND

Local management for vestibular schwannoma (VS) is associated with excellent local control with focus on preserving long-term serviceable hearing. Fractionated proton radiation therapy (FPRT) may be associated with greater hearing preservation because of unique dosimetric properties of proton radiotherapy.

OBJECTIVE

To investigate hearing preservation rates of FPRT in adults with VS and secondarily assess local control and treatment-related toxicity.

METHODS

A prospective, single-arm, phase 2 clinical trial was conducted of patients with VS from 2010 to 2019. All patients had serviceable hearing at baseline and received FPRT to a total dose of 50.4 to 54 Gy relative biological effectiveness (RBE) over 28 to 30 fractions. Serviceable hearing preservation was defined as a Gardner-Robertson score of 1 to 2, measured by a pure tone average (PTA) of ≤50 dB and a word recognition score (WRS) of ≥50%.

RESULTS

Twenty patients had a median follow-up of 4.0 years (range 1.0-5.0 years). Local control at 4 years was 100%. Serviceable hearing preservation at 1 year was 53% (95% CI 29%-76%), and primary end point was not yet reached. Median PTA and median WRS both worsened 1 year after FPRT (P < .0001). WRS plateaued after 6 months, whereas PTA continued to worsen up to 1 year after FPRT. Median cochlea D90 was lower in patients with serviceable hearing at 1 year (40.6 Gy [RBE] vs 46.9 Gy [RBE]), trending toward Wilcoxon rank-sum test statistical significance (P = .0863). Treatment was well-tolerated, with one grade 1 cranial nerve V dysfunction and no grade 2+ cranial nerve dysfunction.

CONCLUSION

FPRT for VS did not meet the goal of serviceable hearing preservation. Higher cochlea doses trended to worsening hearing preservation, suggesting that dose to cochlea correlates with hearing preservation independent of treatment modality.

Recent Advances and Applications of Radiation Therapy for Brain Metastases

PURPOSE OF REVIEW

Radiation therapy (RT) is a mainstay of treatment for brain metastases from solid tumors. Treatment of these patients is complex and should focus on minimizing symptoms, preserving functional status, and prolonging survival.

RECENT FINDINGS

Whole-brain radiotherapy (WBRT) can lead to toxicity, and while it does reduce recurrence in the CNS, this has not been shown to provide a survival benefit. Recent advances focus on reducing the toxicity of WBRT or using more targeted radiation therapy. New paradigms including the use of proton RT for leptomeningeal metastases (LM) and stereotactic radiosurgery (SRS) before craniotomy hold promise in improving treatment efficacy and reducing toxicity. Omission or replacement of WBRT is often safe and the use of SRS is expanding to include patients with more lesions and preoperative RT. Proton RT holds promise for LM. Progress is being made in improving patient-centered outcomes and reducing toxicity for patients with brain metastases.

Outcomes of HPV-Associated Squamous Cell Carcinoma of the Head and Neck: Impact of Race and Socioeconomic Status

BACKGROUND

Socioeconomic factors affecting outcomes of HPV-associated squamous cell carcinoma of the head and neck (SCCHN) are poorly characterized.

METHODS

A custom SEER database identified adult patients with primary nonmetastatic SCCHN and known HPV status diagnosed in 2013 through 2014. Multivariable logistic regression defined associations between patient characteristics and HPV status, with adjusted odds ratios (aORs) and 95% confidence intervals reported. Fine-Gray competing risks regression estimated adjusted hazard ratios (aHRs) and 95% confidence intervals for cancer-specific mortality (CSM), including a disease subsite * HPV status * race interaction term.

RESULTS

A total of 4,735 patients with nonmetastatic SCCHN and known HPV status were identified. HPV-associated SCCHN was positively associated with an oropharyngeal primary, male sex, and higher education, and negatively associated with uninsured status, single marital status, and nonwhite race (P≤.01 for all). For HPV-positive oropharyngeal SCCHN, white race was associated with lower CSM (aHR, 0.55; 95% CI, 0.34-0.88; P=.01) and uninsured status was associated with higher CSM (aHR, 3.12; 95% CI, 1.19-8.13; P=.02). These associations were not observed in HPV-negative or nonoropharynx SCCHN. Accordingly, there was a statistically significant disease subsite * HPV status * race interaction (Pinteraction<.001).

CONCLUSIONS

Nonwhite race and uninsured status were associated with worse CSM in HPV-positive oropharyngeal SCCHN, whereas no such associations were observed in HPV-negative or nonoropharyngeal SCCHN. These results suggest that despite having clinically favorable disease, nonwhite patients with HPV-positive oropharyngeal SCCHN have worse outcomes than their white peers. Further work is needed to understand and reduce socioeconomic disparities in SCCHN.

Trimodality therapy for HPV-positive oropharyngeal cancer: A population-based study: Trimodality therapy for HPV+ OPC

BACKGROUND

Although HPV status is a well-established prognostic factor in oropharyngeal squamous cell carcinoma (OPSCC), approximately 20% of HPV-positive patients die from their disease. We therefore sought to ascertain whether there is a benefit to trimodality therapy with surgery among patients with locally advanced (LA) disease receiving chemoradiation.

METHODS

The SEER Head and Neck with HPV Status Database identified adult patients with non-metastatic OPSCC between 2013 and 2014 with known HPV status who received chemoradiation as part of definitive treatment. The primary outcome was cancer-specific mortality (CSM) for locally-advanced (LA) (T3-T4, or N2-N3, per AJCC 7) versus early-stage (ES) (T1-T2 and N0-N1) disease, stratified by HPV status. The secondary outcome was overall survival (OS).

RESULTS

Among 2974 patients who met study criteria, 671 patients (22.6%) received upfront surgery (trimodality therapy). In the LA setting, there was a significant reduction in CSM with trimodality therapy compared to chemoradiation alone in HPV-positive (Adjusted Hazard Ratio [AHR] 0.19, 95% Confidence Interval [CI] 0.04-0.80; P = 0.024), but not HPV-negative disease [Pinteraction = 0.04]. There was no benefit to trimodality therapy for ES disease, regardless of HPV status. There was also an improvement in OS with trimodality therapy for HPV-positive LA patients (AHR = 0.28, p = 0.006, 95% CI = 0.11-0.70). In contrast, trimodality therapy was not associated with improved OS for HPV-negative patients regardless of stage.

CONCLUSIONS

HPV status may predict for improved outcomes with surgery/trimodality therapy in LA OPSCC. Our findings support prospective investigations to optimize care for the subset of HPV-positive patients who are at greatest risk of cancer death, where trimodality therapy may be appropriate.

Conservative management of low-risk prostate cancer among young versus older men in the United States: Trends and outcomes from a novel national database

BACKGROUND

Management for men aged ≤55 years with low-risk prostate cancer (LRPC) is debated given quality-of-life implications with definitive treatment versus the potential missed opportunity for cure with conservative management. The objective of this study was to define rates of conservative management for LRPC and associated short-term outcomes in young versus older men in the United States.

METHODS

The nonpublic Surveillance, Epidemiology, and End Results Prostate with Active Surveillance/Watchful Waiting (AS/WW) Database identified 50,302 men who were diagnosed with LRPC from 2010 through 2015. AS/WW rates in the United States were stratified by age (≤55 vs ≥56 years). Prostate cancer-specific mortality and overall mortality were defined by initial management type (AS/WW vs definitive treatment [referent]) and age.

RESULTS

AS/WW utilization increased from 8.61% (2010) to 34.56% (2015) among men aged ≤55 years (P for trend <0.001) and from 15.99% to 43.81% among men aged ≥56 years (P for trend <.001). Among patients who had ≤2 positive biopsy cores, AS/WW rates increased from 12.90% to 48.78% for men aged ≤55 years and from 21.85% to 58.01% for men aged ≥56 years. Among patients who had ≥3 positive biopsy cores, AS/WW rates increased from 3.89% to 22.45% for men aged ≤55 years and from 10.05% to 28.49% for men aged ≥56 years (all P for trend <.001). Five-year prostate cancer-specific mortality rates were <0.30% across age and initial management type subgroups.

CONCLUSIONS

AS/WW rates quadrupled for patients aged ≤55 years from 2010 to 2015, with favorable short-term outcomes. These findings demonstrate the short-term safety and increasing acceptance of AS/WW for both younger and older patients. However, there are still higher absolute rates of AS/WW in older patients (P < .001), suggesting some national ambivalence toward AS/WW in younger patients.

Safety of combining radiotherapy with immune-checkpoint inhibition

Immune-checkpoint inhibitors targeting cytotoxic T- lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), or programmed cell death 1 ligand 1 (PD-L1) have transformed the care of patients with a wide range of advanced-stage malignancies. More than half of these patients will also have an indication for treatment with radiotherapy. The effects of both radiotherapy and immune-checkpoint inhibition (ICI) involve a complex interplay with the innate and adaptive immune systems, and accumulating evidence suggests that, under certain circumstances, the effects of radiotherapy synergize with those of ICI to augment the antitumour responses typically observed with either modality alone and thus improve clinical outcomes. However, the mechanisms by which radiotherapy and immune-checkpoint inhibitors synergistically modulate the immune response might also affect both the type and severity of treatment-related toxicities. Moreover, in patients receiving immune-checkpoint inhibitors, the development of immune-related adverse events has been linked with superior treatment responses and patient survival durations, suggesting a relationship between the antitumour and adverse autoimmune effects of these agents. In this Review, we discuss the emerging data on toxicity profiles related to immune-checkpoint inhibitors and radiotherapy, both separately and in combination, their potential mechanisms, and the approaches to managing these toxicities.

Sex Disparity and Copy Number Alterations in Esophageal Squamous Cell Carcinoma

Although sex differences in the incidence of esophageal cancer are well-established, the independent prognostic value of sex remains unclear. Recently, several groups have performed comprehensive molecular analyses of esophageal tumors,¹ providing the opportunity to elucidate the underlying genomic bases for epidemiologic observations. We therefore sought to evaluate the effect of sex on esophageal cancer prognosis and to compare genomic data from tumors in men versus women.

Palliative Radiation Therapy for Vertebral Metastases and Metastatic Cord Compression in Patients Treated With Anti-PD-1 Therapy

Background: There is increasing use of immune checkpoint blockade (ICB) across multiple cancer types, including in patients at risk for vertebral metastases and cord compression. These patients are often treated with palliative radiotherapy (PRT); however, data evaluating the combination of PRT and ICB in patients with vertebral metastases is limited. Furthermore, patients with cord compression are generally excluded from prospective clinical trials. Therefore, we retrospectively evaluated outcomes following PRT and PD-1 inhibition in patients with vertebral metastases. Methods: We performed a retrospective chart review of 37 consecutive patients (total 57 lesions) treated with radiation for vertebral metastases who also received PD-1 inhibition. Patient, treatment and outcomes data were abstracted from the medical records. Results: Histologies included non-small cell lung cancer (n = 21), renal cell carcinoma (n = 9) and melanoma (n = 7). Out of 57 lesions,18 involved >1 segments of the vertebral column. There were isolated lesions in thoracic (16), lumbar (9), cervical (6), and sacral (8) vertebrae. Presenting symptoms included pain (19), numbness (10), and weakness (3). Eleven patients were asymptomatic. Radiologic cord compression was present in 12, epidural extension in 28 and compression fracture in 14. Eleven patients underwent surgical decompression prior to the onset of RT. Median radiation dose was 24 Gy (range 8-30 Gy). Stereotactic radiation was delivered in 4 patients; 33 patients received conformal RT. 21 patients received PD-1 inhibition after RT, 9 before RT and 7 with RT. Seven patients received concurrent CTLA-4 inhibitors with anti-PD-1 therapy. Treatment was in general well-tolerated. Toxicities included fatigue (6), transient pain flare (1), nausea/vomiting (1) and G1 skin changes (1). All patients reported some degree of pain relief. Numbness/weakness was improved in 6 of 13 patients with baseline symptoms (46%) and this was more likely in patients that received vertebral radiation after starting PD-1 inhibitors (71 vs. 17%, p = 0.04). Most patients (22 of 33 evaluable patients, 67%) had stability of irradiated lesions on subsequent follow up imaging performed at median of 30 days from RT, whereas 3 had a complete local response and 4 had a partial local response. Conclusions: We demonstrate that PRT administered to vertebral metastases was well-tolerated and effective in patients treated with PD-1 inhibitors. There was an encouraging rate of pain reduction and neurological improvement.

Time to Prostate-specific Antigen Nadir and the Risk of Death From Prostate Cancer Following Radiation and Androgen Deprivation Therapy

OBJECTIVE

To assess whether the time to prostate-specific antigen (PSA) nadir (TTN) has differential prognostic value in men who reach an undetectable vs detectable PSA nadir.

METHODS

Two hundred and four men from a prospective randomized controlled trial involving radiation therapy with or without 6 months of androgen deprivation therapy in unfavorable risk Prostate cancer (CaP) at academic or community based centers in Massachusetts, enrolled between 1995 and 2001. Adjusted hazard ratios (AHR) of the risk of CaP-specific mortality calculated using Fine and Gray competing risk regression.

RESULTS

After a median follow-up of 18.17years, 160 men died; 30 (18.75%) of CaP. Among men with a PSA nadir ≥ 0.2ng/ml, a TTN < median (12 months) was significantly associated with an increased CaP-specific mortality-risk vs the median or more (AHR 5.07, 95% CI 2.10-12.23, P <.001); whereas this association was not observed among men with a PSA nadir of < 0.2ng/mL, (AHR 9.9, 95% CI 0.23-433.8, P = .23).

CONCLUSION

Men with both a short TTN and detectable PSA nadir could be considered for entry on randomized controlled trials at a novel entry point prior to PSA failure at the time of PSA nadir to completeplanned conventional androgen deprivation therapy vs that plus agent(s) shown to improve outcomes in men with or at high risk of having castrate-resistant CaP.

Multicenter Evaluation of the Tolerability of Combined Treatment With PD-1 and CTLA-4 Immune Checkpoint Inhibitors and Palliative Radiation Therapy

PURPOSE

To analyze immune-related adverse events (ir-AEs) in patients treated with radiation and immune checkpoint blockade.

METHODS AND MATERIALS

We retrospectively reviewed records from patients with metastatic non-small cell lung cancer, melanoma, or renal cell cancer who received at least 1 cycle of a CTLA-4 or PD-1 inhibitor and radiation. Immune-related adverse events, defined using Common Terminology Criteria for Adverse Events version 4.0, were tabulated in relation to treatment variables, and associations with sequencing and timing were assessed.

RESULTS

We identified 133 patients, of whom 28 received a CTLA-4 inhibitor alone, 88 received a PD-1 inhibitor alone, and 17 received both classes of inhibitors either sequentially (n=13) or concurrently (n=4). Fifty-six patients received radiation within 14 days of an immune checkpoint inhibitor. Forty-six patients experienced at least 1 ir-AE (34.6%). Patients receiving both CTLA-4 and PD-1 inhibitors experienced more any-grade ir-AEs as compared with either individually (71% vs 29%, P=.0008). Any-grade ir-AEs occurred in 39% of patients in whom radiation was administered within 14 days of immunotherapy, compared with 23% of other patients (P=.06) and more often in patients who received higher equivalent dose in 2-Gy fractions (EQD2) EQD2 (P=.01). However, most toxicities were mild. There were no associations between site irradiated and specific ir-AEs.

CONCLUSIONS

Our data suggest the combination of focal palliative radiation and CTLA-4 and/or PD-1 inhibitors is well tolerated, with manageable ir-AEs that did not seem to be associated with the particular site irradiated. Although conclusions are limited by the heterogeneity of patients and treatments, and future confirmatory studies are needed, this information can help guide clinical practice for patients receiving immune checkpoint therapy who require palliative radiation therapy.

YU238259 Is a Novel Inhibitor of Homology-Dependent DNA Repair That Exhibits Synthetic Lethality and Radiosensitization in Repair-Deficient Tumors

Radiotherapy and DNA-damaging chemotherapy are frequently utilized in the treatment of solid tumors. Innate or acquired resistance to these therapies remains a major clinical challenge in oncology. The development of small molecules that sensitize cancers to established therapies represents an attractive approach to extending survival and quality of life in patients. Here, we demonstrate that YU238259, a member of a novel class of DNA double-strand break repair inhibitors, exhibits potent synthetic lethality in the setting of DNA damage response and DNA repair defects. YU238259 specifically inhibits homology-dependent DNA repair, but not non-homologous end-joining, in cell-based GFP reporter assays. Treatment with YU238259 is not only synergistic with ionizing radiation, etoposide, and PARP inhibition, but this synergism is heightened by BRCA2 deficiency. Further, growth of BRCA2-deficient human tumor xenografts in nude mice is significantly delayed by YU238259 treatment even in the absence of concomitant DNA-damaging therapy. The cytotoxicity of these small molecules in repair-deficient cells results from an accumulation of unresolved DNA double-strand breaks. These findings suggest that YU238259 or related small molecules may have clinical benefit to patients with advanced BRCA2-negative tumors, either as a monotherapy or as an adjuvant to radiotherapy and certain chemotherapies.

IMPLICATIONS

We have identified a novel series of compounds that demonstrate synthetic lethality in DNA repair-deficient cell and animal models and have strong potential for clinical translation.