Secondary Endpoint Utilization and Publication Rate among Phase III Oncology Trials.

Secondary endpoints (SEP) provide crucial information in the interpretation of clinical trials, but their features are not yet well understood. Thus, we sought to empirically characterize the scope and publication rate of SEPs among late-phase oncology trials. We assessed SEPs for each randomized, published phase III oncology trial across all publications and ClinicalTrials.gov, performing logistic regressions to evaluate associations between trial characteristics and SEP publication rates. After screening, a total of 280 trials enrolling 244,576 patients and containing 2,562 SEPs met the inclusion criteria. Only 22% of trials (62/280) listed all SEPs consistently between ClinicalTrials.gov and the trial protocol. The absolute number of SEPs per trial increased over time, and trials sponsored by industry had a greater number of SEPs (median 9 vs. 5 SEPs per trial; P < 0.0001). In total, 69% of SEPs (1,770/2,562) were published. The publication rate significantly varied by SEP category [X2 (5, N = 2,562) = 245.86; P < 0.001]. SEPs that place the most burden on patients, such as patient-reported outcomes and translational correlatives, were published at 63% (246/393) and 44% (39/88), respectively. Trials with more SEPs were associated with lower overall SEP publication rates. Overall, our findings are that SEP publication rates in late-phase oncology trials are highly variable based on the type of SEP. To avoid undue burden on patients and promote transparency of findings, trialists should weigh the biological and clinical relevance of each SEP together with its feasibility at the time of trial design. SIGNIFICANCE: In this investigation, we characterized the utilization and publication rates of SEPs among late-phase oncology trials. Our results draw attention to the proliferation of SEPs in recent years. Although overall publication rates were high, underpublication was detected among endpoints that may increase patient burden (such as translational correlatives and patient-reported outcomes).

Improvement in visual outcomes of patients with base of skull meningioma as a result of evolution in the treatment techniques in the last three decades: a systematic review.

PURPOSE: We systematically reviewed visual outcomes over the last three decades in patients undergoing treatment for base of skull (BOS) meningiomas and provide recommendations to preserve vision. METHODS: In accordance with the PRISMA guidelines for systematic reviews, a search was conducted from 6/1/2022-9/1/2022 using PubMed and Web of Science. Inclusion criteria included (1) patients treated for BOS meningiomas (2) treatment modality specified (3) specifics of surgical techniques and/or dose/fractions of radiotherapy (4) individual patient outcomes of treatment. Each study was assessed for bias based on study design and heterogeneity of results. RESULTS: A total of 50 studies were included (N = 2911). When comparing improved vision versus unchanged or worsened vision, studies investigating surgery alone published from 2006 and onward had significantly better visual outcomes compared to pre-2006 studies (p = 0.02). When comparing improved vision versus unchanged or worsened vision, studies investigating combined therapy with surgery and radiation published from 2008 and onward had significantly better visual outcomes compared to pre-2008 studies (p < 0.01). Combined modality therapy was less likely to worsen vision compared to either surgery or radiation monotherapy (p < 0.01). However, surgery and radiation monotherapy were more likely to actually improve outcomes compared to combination therapy (p < 0.01). CONCLUSION: For over a decade we have observed improvement in visual outcomes in patients managed for meningioma of BOS, likely attributing the innovation in microsurgical and more targeted and conformal radiation techniques. Combination therapy may be the safest option for preventing worsening of vision, but the highest rates of improving visual function are achieved through monotherapy when indicated.

Prevalence, trends, and characteristics of trials investigating local therapy in contemporary phase 3 clinical cancer research.

BACKGROUND: Although most patients with cancer are treated with local therapy (LT), the proportion of late-phase clinical trials investigating local therapeutic interventions is unknown. The purpose of this study was to determine the proportion, characteristics, and trends of phase 3 cancer clinical trials assessing the therapeutic value of LT over time. METHODS: This was a cross-sectional analysis of interventional randomized controlled trials in oncology published from 2002 through 2020 and registered on ClinicalTrials.gov. Trends and characteristics of LT trials were compared to all other trials. RESULTS: Of 1877 trials screened, 794 trials enrolling 584,347 patients met inclusion criteria. A total of 27 trials (3%) included a primary randomization assessing LT compared with 767 trials (97%) investigating systemic therapy or supportive care. Annual increase in the number of LT trials (slope [m] = 0.28; 95% confidence interval [CI], 0.15-0.39; p < .001) was outpaced by the increase of trials testing systemic therapy or supportive care (m = 7.57; 95% CI, 6.03-9.11; p < .001). LT trials were more often sponsored by cooperative groups (22 of 27 [81%] vs. 211 of 767 [28%]; p < .001) and less often sponsored by industry (5 of 27 [19%] vs. 609 of 767 [79%]; p < .001). LT trials were more likely to use overall survival as primary end point compared to other trials (13 of 27 [48%] vs. 199 of 767 [26%]; p = .01). CONCLUSIONS: In contemporary late-phase oncology research, LT trials are increasingly under-represented, under-funded, and evaluate more challenging end points compared to other modalities. These findings strongly argue for greater resource allocation and funding mechanisms for LT clinical trials. PLAIN LANGUAGE SUMMARY: Most people who have cancer receive treatments directed at the site of their cancer, such as surgery or radiation. We do not know, however, how many trials test surgery or radiation compared to drug treatments (that go all over the body). We reviewed trials testing the most researched strategies (phase 3) completed between 2002 and 2020. Only 27 trials tested local treatments like surgery or radiation compared to 767 trials testing other treatments. Our study has important implications for funding research and understanding cancer research priorities.

Incidence of Primary End Point Changes Among Active Cancer Phase 3 Randomized Clinical Trials.

Importance: Primary end point (PEP) changes to an active clinical trial raise questions regarding trial quality and the risk of outcome reporting bias. It is unknown how the frequency and transparency of the reported changes depend on reporting method and whether the PEP changes are associated with trial positivity (ie, the trial met the prespecified statistical threshold for PEP positivity). Objectives: To assess the frequency of reported PEP changes in oncology randomized clinical trials (RCTs) and whether these changes are associated with trial positivity. Design, Setting, and Participants: This cross-sectional study used publicly available data for complete oncology phase 3 RCTs registered in ClinicalTrials.gov from inception through February 2020. Main Outcomes and Measures: The main outcome was change between the initial PEP and the final reported PEP, assessed using 3 methods: (1) history of tracked changes on ClinicalTrials.gov, (2) self-reported changes noted in the article, and (3) changes reported within the protocol, including all available protocol documents. Logistic regression analyses were performed to evaluate whether PEP changes were associated with US Food and Drug Administration approval or trial positivity. Results: Of 755 included trials, 145 (19.2%) had PEP changes found by at least 1 of the 3 detection methods. Of the 145 trials with PEP changes, 102 (70.3%) did not have PEP changes disclosed within the manuscript. There was significant variability in rates of PEP detection by each method (χ2 = 72.1; P < .001). Across all methods, PEP changes were detected at higher rates when multiple versions of the protocol (47 of 148 [31.8%]) were available compared with 1 version (22 of 134 [16.4%]) or no protocol (76 of 473 [16.1%]) (χ2 = 18.7; P < .001). Multivariable analysis demonstrated that PEP changes were associated with trial positivity (odds ratio, 1.86; 95% CI, 1.25-2.82; P = .003). Conclusions and Relevance: This cross-sectional study revealed substantial rates of PEP changes among active RCTs; PEP changes were markedly underreported in published articles and mostly occurred after reported study completion dates. Significant discrepancies in the rate of detected PEP changes call into question the role of increased protocol transparency and completeness in identifying key changes occurring in active trials.

Multi-institution analysis of tumor mutational burden and outcomes in pediatric central nervous system tumor patients.

BACKGROUND: Pediatric central nervous system (CNS) tumors are the leading cause of pediatric cancer mortality. Research addressing genomic biomarkers and clinical outcomes is needed to inform therapeutic decision-making. METHODS: We conducted a retrospective analysis of pediatric patients (age <21) diagnosed with a primary CNS tumor at four upstate New York hospitals from 2008 to 2021. Clinical and histopathologic data were identified from each patient, including genomic analysis of somatic mutations and tumor mutational burden (TMB) where available. These variables were each compared with overall survival using Cox regression analyses. Multivariable analysis was conducted to identify patient characteristics that may independently predict survival. RESULTS: We identified 119 patients. Common tumor types included low-grade glioma (N = 51), high-grade glioma (N = 29), and medulloblastoma (N = 11). Common driver mutations included TP53 inactivation (N = 16), BRAF-KIAA1549 fusion (N = 16), FGFR1 amplification (N = 12), BRAF V600E mutation (N = 12), NF1 loss (N = 12), and H3F3A K28M mutation (N = 6). Median TMB was one mutation/megabase (mut/Mb, range = 0-132). Overall survival was 79.9%. Variables associated with poorer survival on univariable analysis were higher TMB (p = .002, HR 4.97), high-grade tumors (p = .009, HR 84.3), and high-grade glioma histology (p = .021, HR 3.14). Multivariable analyses further identified TMB (p = .011, HR 4.46) and high-grade histology (p = .015, HR 5.28) as independently predictive of worse survival. Tumor progression was more common in high-TMB (N = 15, 44%) than in low-TMB tumors (N = 19, 35%). CONCLUSIONS: High TMB is correlated with higher rates of progression and death as compared to low-TMB tumors. These findings may help identify patients who may benefit from alternative treatments, such as immunotherapies.

Inclusion of premenopausal women in breast cancer clinical trials.

BACKGROUND: Patients with premenopausal breast cancer (PMBC) have been historically excluded from some clinical trials because of the limitations of using endocrine therapy (ET) in this population. We analyzed breast cancer randomized clinical trials (RCTs) to determine the rates of and factors associated with inclusion of PMBC patients to provide a benchmark for PMBC inclusion in RCTs moving forward. METHODS: Using ClinicalTrials.Gov, we identified breast cancer phase III RCTs and extracted inclusion criteria and patient enrollment information. Multiple binary logistic regression modeling was used to assess trial-related factors that were associated with PMBC patient inclusion. RESULTS: Of 170 breast cancer RCTs identified, 131 (77.1%) included PMBC patients. Sixty-five (38.2%) trials analyzed patients with hormone-receptor-positive (HR+) and HER2-negative (HER2-) breast cancer, of which 31 (47.7%) allowed for enrollment of PMBC patients. Lower rates of PMBC inclusion were seen in trials that studied HR+/HER2-patients (47.7% PMBC inclusion in HR+/HER2-trials vs. 94.3% in non-HR+/HER2-trials, aOR 0.07 [95% CI: 0.02-0.19], p < 0.001) and in trials that randomized or mandated ET (44.4% in ET trials vs. 83.2% in non-ET trials, aOR 0.21 [95% CI: 0.10-0.83], p = 0.02). Trials studying chemotherapy (CT) were associated with inclusion of PMBC patients (100% in CT trials vs. 70.5% in non-CT trials, a OR 14.02 [95% CI: 1.54-127.91], p = 0.01). All surgical and radiation therapy clinical trials allowed for the inclusion of PMBC patients in their eligibility criteria. CONCLUSIONS: Breast cancer clinical trials should carefully select their enrollment criteria and consider inclusion of premenopausal patients when appropriate.

The potential of biology-guided radiation therapy in thoracic cancer: A preliminary treatment planning study.

Purpose: We investigated the feasibility of biology-guided radiotherapy (BgRT), a technique that utilizes real-time positron emission imaging to minimize tumor motion uncertainties, to spare nearby organs at risk. Methods: Volumetric modulated arc therapy (VMAT), intensity-modulated proton (IMPT) therapy, and BgRT plans were created for a paratracheal node recurrence (case 1; 60 Gy in 10 fractions) and a primary peripheral left upper lobe adenocarcinoma (case 2; 50 Gy in four fractions). Results: For case 1, BgRT produced lower bronchus V40 values compared to VMAT and IMPT. For case 2, total lung V20 was lower in the BgRT case compared to VMAT and IMPT. Conclusions: BgRT has the potential to reduce the radiation dose to proximal critical structures but requires further detailed investigation.

Association between Prior Malignancy Exclusion Criteria and Age Disparities in Cancer Clinical Trials.

Prior malignancy exclusion criteria (PMEC) are often utilized in cancer clinical trials; however, the incidence of PMEC and the association of PMEC with trial participant age disparities remain poorly understood. This study aimed to identify age disparities in oncologic randomized clinical trials as a result of PMEC. Using a comprehensive collection of modern phase III cancer clinical trials obtained via ClinicalTrials.gov, we assessed the incidence and covariates associated with trials excluding patients with prior cancers within 5+ years from registration (PMEC-5). Using the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database, we further sought to determine the correlation between PMEC-5 and age disparities. PMEC-5 were used in 41% of all trials, with higher PMEC-5 utilization among industry-supported trials as well as trials evaluating a targeted therapy. Comparing trial patient median ages with population-matched median ages by disease site and time-period, we assessed the association between PMEC-5 and age disparities among trial participants. PMEC-5 were independently associated with heightened age disparities, which further worsened with longer exclusionary timeframes. Together, PMEC likely contribute to age disparities, suggesting that eligibility criteria modernization through narrower PMEC timeframes may work toward reducing such disparities in cancer clinical trial enrollment.

High Plus Low Dose Radiation Strategy in Combination with TIGIT and PD1 Blockade to Promote Systemic Antitumor Responses.

Tumors deploy various immune-evasion mechanisms that create a suppressive environment and render effector T-cells exhausted and inactive. Therefore, a rational utilization of checkpoint inhibitors may alleviate exhaustion and may partially restore antitumor functions. However, in high-tumor-burden models, the checkpoint blockade fails to maintain optimal efficacy, and other interventions are necessary to overcome the inhibitory tumor stroma. One such strategy is the use of radiotherapy to reset the tumor microenvironment and maximize systemic antitumor outcomes. In this study, we propose the use of anti-PD1 and anti-TIGIT checkpoint inhibitors in conjunction with our novel RadScopal technique to battle highly metastatic lung adenocarcinoma tumors, bilaterally established in 129Sv/Ev mice, to mimic high-tumor-burden settings. The RadScopal approach is comprised of high-dose radiation directed at primary tumors with low-dose radiation delivered to secondary tumors to improve the outcomes of systemic immunotherapy. Indeed, the triple therapy with RadScopal + anti-TIGIT + anti-PD1 was able to prolong the survival of treated mice and halted the growth of both primary and secondary tumors. Lung metastasis counts were also significantly reduced. In addition, the low-dose radiation component reduced TIGIT receptor (PVR) expression by tumor-associated macrophages and dendritic cells in secondary tumors. Finally, low-dose radiation within triple therapy decreased the percentages of TIGIT+ exhausted T-cells and TIGIT+ regulatory T-cells. Together, our translational approach provides a new treatment alternative for cases refractory to other checkpoints and may bring immunotherapy into a new realm of systemic disease control.

The radiotherapy quality assurance gap among phase III cancer clinical trials.

PURPOSE: Quality assurance (QA) practices improve the quality level of oncology trials by ensuring that the protocol is followed and the results are valid and reproducible. This study investigated the utilization of QA among randomized controlled trials that involve radiotherapy (RT). METHODS AND MATERIALS: We searched ClinicalTrials.gov in February 2020 for all phase III oncology randomized clinical trials (RCTs). These trials were screened for RT-specific RCTs that had published primary trial results. Information regarding QA in each trial was collected from the study publications and trial protocol if available. Two individuals independently performed trial screening and data collection. Pearson's Chi-square tests analyses were used to assess factors that were associated with QA inclusion in RT trials. RESULTS: Forty-two RCTs with RT as the primary intervention or as a mandatory component of the protocol were analyzed; the earliest was started in 1994 and one trial was still active though not recruiting. Twenty-nine (69%) trials mandated RT quality assurance (RTQA) practices as part of the trial protocol, with 19 (45%) trials requiring institutional credentialing. Twenty-one (50%) trials published protocol deviation outcomes. Clinical trials involving advanced radiation techniques (IMRT, VMAT, SRS, SBRT) did not include more RTQA than trials without these advanced techniques (73% vs. 65%, p = 0.55). Trials that reported protocol deviation outcomes were associated with mandating RTQA in their protocols as compared to trials that did not report these outcomes (100% vs. 38%, p < 0.001). CONCLUSIONS: There is a lack of RTQA utilization and transparency in RT clinical trials. It is imperative for RT trials to include increased QA for safe, consistent, and high-quality RT planning and delivery.

Pulsed Radiation Therapy to Improve Systemic Control of Metastatic Cancer.

Radiation therapy (RT) is emerging as an interventional modality in the cancer-immunity cycle, augmenting the activation of an adaptive immune response against tumors. RT, particularly in combination with immunotherapy, can enhance immune memory effects and shape the tumor-directed T-cell populations. However, a single cycle of RT delivered to a limited number of polymetastatic lesions is rarely sufficient to achieve systemic control. We hypothesize that several rounds of RT, akin to several rounds of immunotherapeutic drugs, is likely to provide greater clinical benefit to patients with metastatic disease. We propose that the repeated exposure to tumor antigens released by "pulsed-RT" (i.e., treating 2-4 tumor lesions with 3 irradiation cycles given one month apart) may amplify the adaptive immune response by expanding the tumor-specific T-cell receptor repertoire, the production of high-affinity tumor antibodies, and the generation of memory lymphocytes and thereby improve immune control of systemic disease.

High-dose irradiation in combination with non-ablative low-dose radiation to treat metastatic disease after progression on immunotherapy: Results of a phase II trial.

AIM: To report early findings from a phase II trial of high-dose radiotherapy (HD-RT) with or without low-dose RT (LD-RT) for metastatic cancer. METHODS: Eligible patients had metastatic disease that progressed on immunotherapy within 6 months. Patients were given either HD-RT (20-70 Gy total; 3-12.5 Gy/f), or HD-RT + LD-RT (0.5-2 Gy/f up to 1-10 Gy total) to separate lesions, with continued immunotherapy. Radiographic response was assessed per RECIST 1.1 and Immune-Related Response Criteria (irRC). Primary endpoints: (1) 4-month disease control (DCR, complete/partial response [CR/PR] or stable disease [SD]) or an overall response (ORR, CR/PR) at any point in ≥10% of patients, per RECIST 1.1; (2) dose-limiting toxicity within 3 months not exceeding 30%. Secondary endpoint was lesion-specific response. RESULTS: Seventy-four patients (NSCLC, n = 38; melanoma n = 21) were analyzed (39 HD-RT and 35 HD-RT + LD-RT). The median follow-up time was 13.6 months. The primary endpoint was met for 72 evaluable patients, with a 4-month DCR of 42% (47% [16/34] vs. 37% [14/38] in HD-RT + LD-RT vs. HD-RT, P = 0.38), and 19% ORR at any time (26% [9/34] vs. 13% [5/38] in HD-RT + LD-RT vs. HD-RT, P = 0.27). Three patients had toxicity ≥grade 3. LD-RT lesion response (53%) was improved compared to nonirradiated lesions in HD-RT + LD-RT (23%, P = 0.002) and HD-RT (11%, P < 0.001). T- and NK cell infiltration was enhanced in lesions treated with LD-RT. CONCLUSIONS: HD-RT plus LD-RT safely improved lesion-specific response in patients with immune resistant solid tumors by promoting infiltration of effector immune cells into the tumor microenvironment.

Immunotherapy combined with high- and low-dose radiation to all sites leads to complete clearance of disease in a patient with metastatic vaginal melanoma.

A 73-year-old woman with metastatic vaginal mucosal melanoma that had progressed on ipilimumab and nivolumab experienced clinical and radiographic complete response to dual checkpoint inhibitor immunotherapy given in combination with high-dose plus low-dose radiation. General characteristics and treatment options in this disease are highlighted.

Palliative Radiation Therapy for Metastatic, Persistent, or Recurrent Epithelial Ovarian Cancer: Efficacy in the Era of Modern Technology and Targeted Agents.

PURPOSE: Metastatic, persistent, or recurrent epithelial ovarian cancer (MPR-EOC) remains a significant threat to patient mortality despite advances in novel targeted agents. Radiation therapy (RT) is often used as a palliative option. We report outcomes of a large series of MPR-EOC patients treated with modern palliative RT (PRT) in an era of novel systemic therapies. METHODS AND MATERIALS: A retrospective review was conducted of women treated with PRT for MPR-EOC between 2007 and 2019 at an academic institution. Clinical response rates were recorded at <1 month, 1 to 3 months, and >3 months. Radiographic responses were categorized by RECIST 1.1 criteria. Overall response rate (ORR) was the sum of complete and partial response. Linear regression analyses of baseline characteristics were conducted for statistical testing. RESULTS: Eighty-six patients with PMR-OC received 120 courses of palliative RT. Median follow-up was 8.6 months. Median age was 61 (range, 22-82). Thirty-six percent of women received central nervous system (CNS)-directed RT. In addition, 43% received targeted therapies before RT. Clinical ORR within 1 month and at last follow-up for non-CNS lesions was 79% and 61% (69% and 88% for CNS lesions, respectively). High-grade serous lesions were more likely to have clinical response (P = .04). Biologically effective doses (BED) >39 Gy were associated with improved clinical response in CNS lesions (P = .049). Bony sites were associated with worse clinical (P = .004) response in non-CNS lesions compared with soft tissue or nodal sites. Acute or late grade 3+ toxicities with bevacizumab were low (8.7%/4.3%). CONCLUSIONS: PRT offers excellent rates of response for symptomatic patients with MPR-EOC within 1 month of treatment, with durable responses beyond 3 months. High-grade serous lesions were associated with improved response in all patients. Higher BED and soft tissue or nodal sites were associated with improved response in CNS and non-CNS patients, respectively. Acute or late toxicities with bevacizumab and PRT were low. Prospective investigation is warranted to determine the optimal PRT regimen.

A Retrospective Study of Rapid Symptom Response in Bleeding Gynecologic Malignancies With Short Course Palliative Radiation Therapy: Less is More.

CONTEXT: Advanced gynecologic malignancies can cause significant vaginal bleeding. Radiotherapy (RT) is often used to palliate symptoms, but limited data exist concerning the optimal dose and expected time to bleeding hemostasis in this population. OBJECTIVES: 1) To investigate the overall hemostasis response and kinetics of hemostasis in women with gynecologic malignancies receiving palliative RT. 2) To compare the efficacy of short-course RT (SCRT, less than or equal to five fractions, >3.5 Gy per fraction) vs. conventionally fractionated long-course regimens (greater than five fractions). METHODS: We identified women receiving palliative RT for bleeding gynecologic malignancies. Initial and maximal hemostasis responses (IHR and MHR) were recorded and categorized as progressive bleeding (PD), stable disease (SD), partial response (PR), or complete response (CR). Clinical variables were correlated with response or toxicity using binary logistic regression statistical methods. RESULTS: Thirty-three women (median age 63) were identified between 2010 and 2019. Median follow-up and survival after RT were 131 days. About 54.5% (18 of 33) received SCRT. Median time to IHR was five days (two-and-a-half days with SCRT) and 78.8% (26 of 33) responded during treatment. Median time to MHR was 13 days. About 100% achieved PR or CR at MHR. Rates of CR were similar between SCRT (83%) and conventionally fractionated schedules (87%). Average durability of hemostatic control was 5.4 months. Overall rate of rebleeding and Grade 3+ toxicity was 9.1% (3 of 33 each). CONCLUSION: Women receiving SCRT for bleeding gynecologic malignancies achieved rapid symptom control (often during treatment) with minimal rebleeding. In a population whose median survival is four months, SCRT effectively addresses symptomatic disease while minimizing patient burden and toxicity.

Use of Multi-Site Radiation Therapy for Systemic Disease Control.

Metastatic cancer is a heterogeneous entity, some of which could benefit from local consolidative radiation therapy (RT). Although randomized evidence is growing in support of using RT for oligometastatic disease, a highly active area of investigation relates to whether RT could benefit patients with polymetastatic disease. This article highlights the preclinical and clinical rationale for using RT for polymetastatic disease, proposes an exploratory framework for selecting patients best suited for these types of treatments, and briefly reviews potential challenges. The goal of this hypothesis-generating review is to address personalized multimodality systemic treatment for patients with metastatic cancer. The rationale for using high-dose RT is primarily for local control and immune activation in either oligometastatic or polymetastatic disease. However, the primary application of low-dose RT is to activate distinct antitumor immune pathways and modulate the tumor stroma in efforts to better facilitate T cell infiltration. We explore clinical cases involving high- and low-dose RT to demonstrate the potential efficacy of such treatment. We then group patients by extent of disease burden to implement high- and/or low-dose RT. Patients with low-volume disease may receive high-dose RT to all sites as part of an oligometastatic paradigm. Subjects with high-volume disease (for whom standard of care remains palliative RT only) could be treated with a combination of high-dose RT to a few sites for immune activation, while receiving low-dose RT to several remaining lesions to enhance systemic responses from high-dose RT and immunotherapy. We further discuss how emerging but speculative concepts such as immune function may be integrated into this approach and examine therapies currently under investigation that may help address immune deficiencies. The review concludes by addressing challenges in using RT for polymetastatic disease, such as concerns about treatment planning workflows, treatment times, dose constraints for multiple-isocenter treatments, and economic considerations.

Role of Mitochondria in Cancer Immune Evasion and Potential Therapeutic Approaches.

The role of mitochondria in cancer formation and progression has been studied extensively, but much remains to be understood about this complex relationship. Mitochondria regulate many processes that are known to be altered in cancer cells, from metabolism to oxidative stress to apoptosis. Here, we review the evolving understanding of the role of mitochondria in cancer cells, and highlight key evidence supporting the role of mitochondria in cancer immune evasion and the effects of mitochondria-targeted antitumor therapy. Also considered is how knowledge of the role of mitochondria in cancer can be used to design and improve cancer therapies, particularly immunotherapy and radiation therapy. We further offer critical insights into the mechanisms by which mitochondria influence tumor immune responses, not only in cancer cells but also in immune cells. Given the central role of mitochondria in the complex interactions between cancer and the immune system, high priority should be placed on developing rational strategies to address mitochondria as potential targets in future preclinical and clinical studies. We believe that targeting mitochondria may provide additional opportunities in the development of novel antitumor therapeutics.

Phase 1/2 Trial of Pembrolizumab and Concurrent Chemoradiation Therapy for Limited-Stage SCLC.

INTRODUCTION: Few advancements in treating limited-stage SCLC (LS-SCLC) have been made in decades. We report here a phase 1/2 trial of concurrent chemoradiotherapy (CRT) and pembrolizumab. METHODS: This single-center, open-label phase 1/2 study recruited adults with LS-SCLC or other neuroendocrine tumors and good performance status (Eastern Cooperative Oncology Group ≤ 2). The primary end point was safety, as assessed by dose-limiting toxicities. Concurrent CRT consisted of etoposide and a platin with 45 Gy radiotherapy (30 twice daily). Prophylactic cranial irradiation (25 Gy, 10 fractions) was given at the physician's discretion. Pembrolizumab was started concurrently with CRT and continued for up to 16 cycles. The phase 1 portion consisted of a 3 + 3 design. Toxicity was assessed with Common Terminology Criteria for Adverse Events version 4.0. Secondary outcomes were progression-free survival, overall survival, and tumor response as measured by the immune-related response criteria. RESULTS: A total of 45 patients were screened, and 40 were enrolled. All completed radiation therapy and received greater than or equal to one cycle of pembrolizumab. A total of 27 (61%) received percutaneous coronary intervention. One dose-limiting toxicity was observed in the phase 1 portion. There were no grade 5 toxicities, but there were three grade 4 events (two neutropenia, one respiratory failure). Pneumonitis rate was 15% (three grade 2 and three grade 3). All 17 esophagitis events (42.5%) were grades 1 to 2. At median follow-up time of 23.1 months, the median progression-free survival time was 19.7 months (95% confidence interval: 8.8‒30.5) and the median overall survival time was 39.5 months (95% confidence interval: 8.0‒71.0). CONCLUSION: Concurrent CRT and pembrolizumab for LS-SCLC was well tolerated and yielded favorable outcomes, providing a basis for randomized studies.