Differential Treatment Effects of Subgroup Analyses in Phase 3 Oncology Trials From 2004 to 2020

Importance

Subgroup analyses are often performed in oncology to investigate differential treatment effects and may even constitute the basis for regulatory approvals. Current understanding of the features, results, and quality of subgroup analyses is limited.

Objective

To evaluate forest plot interpretability and credibility of differential treatment effect claims among oncology trials.

Design, Setting, and Participants

This cross-sectional study included randomized phase 3 clinical oncology trials published prior to 2021. Trials were screened from ClinicalTrials.gov.

Main Outcomes and Measures

Missing visual elements in forest plots were defined as a missing point estimate or use of a linear x-axis scale for hazard and odds ratios. Multiplicity of testing control was recorded. Differential treatment effect claims were rated using the Instrument for Assessing the Credibility of Effect Modification Analyses. Linear and logistic regressions evaluated associations with outcomes.

Results

Among 785 trials, 379 studies (48%) enrolling 331 653 patients reported a subgroup analysis. The forest plots of 43% of trials (156 of 363) were missing visual elements impeding interpretability. While 4148 subgroup effects were evaluated, only 1 trial (0.3%) controlled for multiple testing. On average, trials that did not meet the primary end point conducted 2 more subgroup effect tests compared with trials meeting the primary end point (95% CI, 0.59-3.43 tests; P = .006). A total of 101 differential treatment effects were claimed across 15% of trials (55 of 379). Interaction testing was missing in 53% of trials (29 of 55) claiming differential treatment effects. Trials not meeting the primary end point were associated with greater odds of no interaction testing (odds ratio, 4.47; 95% CI, 1.42-15.55, P = .01). The credibility of differential treatment effect claims was rated as low or very low in 93% of cases (94 of 101).

Conclusions and Relevance

In this cross-sectional study of phase 3 oncology trials, nearly half of trials presented a subgroup analysis in their primary publication. However, forest plots of these subgroup analyses largely lacked essential features for interpretation, and most differential treatment effect claims were not supported. Oncology subgroup analyses should be interpreted with caution, and improvements to the quality of subgroup analyses are needed.

Association of differential censoring with survival and suboptimal control arms among oncology clinical trials

Differential censoring (DC), referring to censoring imbalance between treatment arms, may bias the interpretation of survival outcomes in clinical trials. In 146 phase 3 oncology trials with statistically significant time-to-event surrogate primary endpoints (PEPs), we evaluated the association between DC in the surrogate PEP, control arm adequacy, and the subsequent statistical significance of OS results. Twenty-four (16%) trials exhibited DC favoring the control arm (ConDC), while 15 (10%) exhibited experimental arm DC (ExpDC). Positive OS was more common in ConDC trials (63%) than trials without DC (37%) or with ExpDC (47%; odds ratio [OR] 2.64, 95% CI 1.10-7.20; P=.04). ConDC trials more frequently used suboptimal control arms (46%) compared to 20% without DC and 13% with ExpDC (OR 3.60, 95% CI 1.29-10.0; P=.007). The presence of ConDC in trials with surrogate PEPs, especially in those with OS conversion, may indicate an inadequate control arm and should be examined and explained.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

FUNDING

Galera Therapeutics.

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.

Prevalence and implications of significance testing for baseline covariate imbalance in randomised cancer clinical trials: The Table 1 Fallacy

BACKGROUND

The 'Table 1 Fallacy' refers to the unsound use of significance testing for comparing the distributions of baseline variables between randomised groups to draw erroneous conclusions about balance or imbalance. We performed a cross-sectional study of the Table 1 Fallacy in phase III oncology trials.

METHODS

From ClinicalTrials.gov, 1877 randomised trials were screened. Multivariable logistic regressions evaluated predictors of the Table 1 Fallacy.

RESULTS

A total of 765 randomised controlled trials involving 553,405 patients were analysed. The Table 1 Fallacy was observed in 25% of trials (188 of 765), with 3% of comparisons deemed significant (59 of 2353), approximating the typical 5% type I error assertion probability. Application of trial-level multiplicity corrections reduced the rate of significant findings to 0.3% (six of 2345 tests). Factors associated with lower odds of the Table 1 Fallacy included industry sponsorship (adjusted odds ratio [aOR] 0.29, 95% confidence interval [CI] 0.18-0.47; multiplicity-corrected P < 0.0001), larger trial size (≥795 versus <280 patients; aOR 0.32, 95% CI 0.19-0.53; multiplicity-corrected P = 0.0008), and publication in a European versus American journal (aOR 0.06, 95% CI 0.03-0.13; multiplicity-corrected P < 0.0001).

CONCLUSIONS

This study highlights the persistence of the Table 1 Fallacy in contemporary oncology randomised controlled trials, with one of every four trials testing for baseline differences after randomisation. Significance testing is a suboptimal method for identifying unsound randomisation procedures and may encourage misleading inferences. Journal-level enforcement is a possible strategy to help mitigate this fallacy.

Superior vena cava syndrome presenting as chylothorax

Chylothorax caused by superior vena cava (SVC) syndrome is a rare but potentially life-threatening complication requiring a multidisciplinary diagnosis and management approach. We present a case of a 27-year-old female with end-stage renal disease who developed chylothorax secondary to SVC syndrome caused by venous stenosis from a tunneled hemodialysis (HD) catheter. The patient had a history of ongoing hemodialysis through a tunneled catheter placed in the right internal jugular vein approximately seven months before presentation. She presented with dyspnea, chest pain, and a large left-sided pleural effusion. A multidisciplinary diagnostic workup and management included 2 thoracentesis, pleural fluid studies, serial radiological tests, right and left heart catheterizations, and blood serum studies with flow cytometry. They revealed that SVC stenosis around the hemodialysis catheter was causing the patient's pathology. The patient underwent veno-plasty of the right SVC and brachiocephalic veins and replacement of HD catheter leading to the resolution of the chylothorax and significant improvement in respiratory symptoms. This report will highlight the approach to diagnosing and managing chylothorax and a review of existing medical literature.

Definitive Liver Radiotherapy for Intrahepatic Cholangiocarcinoma with Extrahepatic Metastases

Introduction

Tumor-related liver failure (TRLF) is the most common cause of death in patients with intrahepatic cholangiocarcinoma (ICC). Though we previously showed that liver radiotherapy (L-RT) for locally advanced ICC is associated with less frequent TRLF and longer overall survival (OS), the role of L-RT for patients with extrahepatic metastatic disease (M1) remains undefined. We sought to compare outcomes for M1 ICC patients treated with and without L-RT.

Methods

We reviewed ICC patients that found to have M1 disease at initial diagnosis at a single institution between 2010 and 2021 who received L-RT, matching them with an institutional cohort by propensity score and a National Cancer Database (NCDB) cohort by frequency technique. The median biologically effective dose was 97.5 Gy (interquartile range 80.5-97.9 Gy) for L-RT. Patients treated with other local therapies or supportive care alone were excluded. We analyzed survival with Cox proportional hazard modeling.

Results

We identified 61 patients who received L-RT and 220 who received chemotherapy alone. At median follow-up of 11 months after diagnosis, median OS was 9 months (95% confidence interval [CI] 8-11) and 21 months (CI: 17-26) for patients receiving chemotherapy alone and L-RT, respectively. TRLF was the cause of death more often in the patients who received chemotherapy alone compared to those who received L-RT (82% vs. 47%; p = 0.001). On multivariable propensity score-matched analysis, associations with lower risk of death included duration of upfront chemotherapy (hazard ratio [HR] 0.82; p = 0.005) and receipt of L-RT (HR: 0.40; p = 0.002). The median OS from diagnosis for NCDB chemotherapy alone cohort was shorter than that of the institutional L-RT cohort (9 vs. 22 months; p < 0.001).

Conclusion

For M1 ICC, L-RT associated with a lower rate of death due to TRLF and longer OS versus those treated with chemotherapy alone. Prospective studies of L-RT in this setting are warranted.

An Interesting Case of Peripartum Cardiomyopathy With Biventricular Thrombi

Peripartum cardiomyopathy (PPCM) is a cause of heart failure that develops within five months postpartum. Biventricular thrombosis is a rare complication of PPCM with only a few cases reported in the literature. Here, we report a case of PPCM with biventricular thrombosis that was successfully treated with medical management.

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.

Dose Escalation for Pancreas SBRT: Potential and Limitations of using Daily Online Adaptive Radiation Therapy and an Iterative Isotoxicity Automated Planning Approach

Purpose

To determine the dosimetric limitations of daily online adaptive pancreas stereotactic body radiation treatment by using an automated dose escalation approach.

Methods and Materials

We collected 108 planning and daily computed tomography (CT) scans from 18 patients (18 patients × 6 CT scans) who received 5-fraction pancreas stereotactic body radiation treatment at MD Anderson Cancer Center. Dose metrics from the original non-dose-escalated clinical plan (non-DE), the dose-escalated plan created on the original planning CT (DE-ORI), and the dose-escalated plan created on daily adaptive radiation therapy CT (DE-ART) were analyzed. We developed a dose-escalation planning algorithm within the radiation treatment planning system to automate the dose-escalation planning process for efficiency and consistency. In this algorithm, the prescription dose of the dose-escalation plan was escalated before violating any organ-at-risk (OAR) dose constraint. Dose metrics for 3 targets (gross target volume [GTV], tumor vessel interface [TVI], and dose-escalated planning target volume [DE-PTV]) and 9 OARs (duodenum, large bowel, small bowel, stomach, spinal cord, kidneys, liver, and skin) for the 3 plans were compared. Furthermore, we evaluated the effectiveness of the online adaptive dose-escalation planning process by quantifying the effect of the interfractional dose distribution variations among the DE-ART plans.

Results

The median D_95% dose to the GTV/TVI/DE-PTV was 33.1/36.2/32.4 Gy, 48.5/50.9/40.4 Gy, and 53.7/58.2/44.8 Gy for non-DE, DE-ORI, and DE-ART, respectively. Most OAR dose constraints were not violated for the non-DE and DE-ART plans, while OAR constraints were violated for the majority of the DE-ORI patients due to interfractional motion and lack of adaptation. The maximum difference per fraction in D_95%, due to interfractional motion, was 2.5 ± 2.7 Gy, 3.0 ± 2.9 Gy, and 2.0 ± 1.8 Gy for the TVI, GTV, and DE-PTV, respectively.

Conclusions

Most patients require daily adaptation of the radiation planning process to maximally escalate delivered dose to the pancreatic tumor without exceeding OAR constraints. Using our automated approach, patients can receive higher target dose than standard of care without violating OAR constraints.

Brain Metastases from Biliary Tract Cancer: Case Series and Clinicogenomic Analysis

BACKGROUND

Limited data from small series have suggested that brain metastases from biliary tract cancers (BrM-BTC) affect ≤2% of patients with BTC. We sought to review our experience with patients with BrM-BTC and to identify associations of tumor-related molecular alterations with outcomes.

MATERIALS AND METHODS

A retrospective review of patients with BTC seen at a tertiary referral center from 2005 to 2021 was performed; patients with BrM-BTC were identified, and clinical and molecular data were collected.

RESULTS

Twenty-one of 823 patients with BTC (2.6%) developed BrM. For patients with BrM-BTC, median follow-up time was 27.9 months after primary BTC diagnosis and 3.1 months after BrM diagnosis. Median time from primary diagnosis to diagnosis of BrM was 14.4 [range, 1.1-66.0] months. Median overall survival (OS) from primary diagnosis was 31.5 [2.9-99.8] months and median OS from BrM diagnosis was 4.2 [0.2-33.8] months. Patients who underwent BrM-directed therapy trended toward longer OS following BrM diagnosis than patients receiving supportive care only (median 6.5 vs 0.8 months, P = .060). The BrM-BTC cohort was enriched for BRAF (30%), PIK3CA (25%), and GNAS (20%) mutations. patients with BrM-BTC with BRAF mutations trended toward longer OS following BrM diagnosis (median 13.1 vs 4.2 months, P = .131).

CONCLUSION

This is the largest series of patients with BrM-BTC to date and provides molecular characterization of this rare subgroup of patients with BTC. Patients with BrM-BTC may be more likely to have BRAF mutations. With advances in targeted therapy for patients with BTC with actionable mutations, continued examination of shifting patterns of failure, with emphasis on BrM, is warranted.

Incidence and impact of proportional hazards violations in phase 3 cancer clinical trials

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Background: Hazard ratio (HR)-based analyses used in oncology trials rely on the assumption of proportional hazards, i.e. a HR that is constant over time. Proportional hazards violations (PHVs) may lead to misinterpretation of trial results. Restricted mean survival time (RMST) is valid with non-proportional hazards and has received recent attention specifically for immunotherapy (IO) trials but has not been routinely adopted in oncology trial design as a whole. We aimed to comprehensively characterize the incidence and factors associated with PHVs among phase 3 oncology trials and assess RMST as an alternate measure of treatment effect in survival analysis. Methods: We used Clinicaltrials.gov to identify all superiority-design, 2-arm phase 3 cancer trials with time-dependent endpoints with published results through February 2020. We manually reconstructed patient-level data from published Kaplan-Meier (KM) curves, assessed PHVs with the Schoenfeld residual test (p <.05) and analyzed the RMST. To assess reconstruction accuracy, reported and reconstructed HRs were compared. Univariable logistic regression was used to assess the likelihood of PHVs by trial characteristic, with statistically significant factors (p <.05) included in a multivariable analysis. Concordance of RMST-based and HR-based analysis was established when both tests agreed as to the statistical significance of the comparison. Results: Of 342 KM comparisons eligible for reconstruction, 318 comparisons across 315 trials, enrolling 347,538 patients from 1989-2017, were accurately reconstructed and analyzed. PHVs were identified in 76/318 (23.9%) trials. There was no difference in likelihood of PHVs among IO vs non-IO trials (LR 2.31, 95% CI 0.30 – 17.85, P =.37), nor by disease site, year of trial initiation, or sample size. Few trials with PHVs (16/76) pre-specified a plan to account for non-proportional hazards in statistical design. Trials with an overall survival (OS) primary endpoint (PEP) were less likely to have PHVs than trials with a non-OS PEP (LR: 0.50, 95% CI 0.28 - 0.90, P =.02). Trials whose PEP was non-significant were more likely to have PHVs (LR 1.73, 95% CI 1.01 - 2.97, P =.047). No factor remained significantly associated with PHV in multivariable analysis. Overall, 291/318 (91.5%) KM comparisons were concordant. Among trials with PHVs, 5/76 were significant by RMST but not HR, and 5/76 were significant by HR but not RMST. Of these, 1 led to FDA drug approval, and 2 others are cited in NCCN guidelines. Conclusions: PHVs are common across all phase 3 cancer clinical trials. Attempts to account for PHVs in trial design are lacking despite the potential for trial misinterpretation in the event of non-proportional hazards. RMST-based analysis is broadly concordant with HR-based analysis and may aid in interpretation of trials with PHVs. Hence, we recommend that prospective trials include a priori a statistical plan to account for PHVs.

Exclusion of Older Adults from Cancer Clinical Trials: Review of the Literature and Future Recommendations

In this review, we present the context of older adult (OA) cancer patients within the broader cancer population, including cancer burdens and trial representation. We first describe the proportion of older adults in clinical trials, with studies showing strong evidence that the proportion of OA in cancer trials is much less than the proportion of OA in the overall cancer population. We highlight the lack of generalizability that can lead to challenges in treatment decisions for OA as well as concerns regarding health inequity. We then discuss barriers to OA enrollment related to trial structure and design, physician perspective, and patient and/or caregiver perspective. We expand on this further by outlining these barriers throughout the process of trial design, patient enrollment/trial implementation, and data analysis in post-market settings. We summarize guidelines from national societies, regulatory agencies, and other institutional bodies, then present a compilation of on-the-ground actionable recommendations to address the challenges of clinical trial design, focusing on geriatric assessments and OA-specific trials. We conclude by providing an outline for future directions, noting specifically the potential impact that radiotherapy and radiation oncology may have on clinical trials related to OA patients.

Gastrointestinal malignancies and supportive care trials: a snapshot of the last two decades

BACKGROUND

Patients with gastrointestinal (GI) cancers experience a high symptom burden due to the effects of both cancer and treatment. As such, trials assessing symptom burden and supportive interventions are crucial. Here, we characterise the landscape of phase III GI cancer clinical trials and explore study outcomes centred on the patient's quality of life (QoL).

METHODS

We searched ClinicalTrials.gov for phase III randomised controlled trials (RCTs) registered between 2000 and 2017 that are assessing a therapeutic intervention in adult patients with cancer and grouped trials by GI disease sites.

RESULTS

Overall, we identified 76 phase III trials specific to GI cancers that enrolled a total of 53 725 patients. When analysing the primary outcomes measured, the vast majority of studies (n=71, 86%) measured disease-related endpoints such as progression-free survival or overall survival. All trials had a secondary endpoint that measured adverse events, but only 30 trials (39%) included QoL measures as secondary endpoints. Of the 30 trials that included QoL secondary endpoints, only 16 (53%) reported these results. Only five trials (7%) assessed interventions aimed at supportive measures impacting disease-related or treatment-related toxicity. None of the supportive trials included QoL as a primary endpoint and only two of these trials (40%) included QoL as a secondary endpoint.

CONCLUSIONS

Most GI cancer trials failed to incorporate patient-centred outcomes or QoL measures when studying new interventions. These findings call for greater integration of patient-reported metrics, which may lead to better care and outcomes for patients with GI malignancies.

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

Simple Summary

Recent studies have shown that the incidence of age disparities in cancer clinical trials may be increasing over time. Excluding patients with prior malignancies is one such eligibility criterion through which elderly may inadvertently be excluded from clinical trial participation. While strict enrollment criteria may improve internal validity of studies, they can also negatively impact generalizability of results. As such, we sought to characterize the incidence of prior malignancy exclusion criteria in phase III cancer clinical trials and assess if this eligibility criterion may directly contribute to age disparities. These data support efforts to modernize eligibility criteria and inform best practices regarding acceptable versus unacceptable exclusionary timeframes for prior malignancy exclusion criteria.

Abstract

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.

Feasibility of administering human pancreatic cancer chemotherapy in a spontaneous pancreatic cancer mouse model

BACKGROUND

Both modified FOLFIRINOX (mFFX) and gemcitabine/nab-paclitaxel chemotherapy regimens have been shown to improve clinical outcomes in patients with pancreatic cancer, and are often used interchangeably as the standard of care. Preclinical studies often do not use these regimens, since administering these multiagent approaches can be difficult. In this study, we assessed the feasibility of administering these two chemotherapy regimens in spontaneous pancreatic tumors using KPC mice with the ultimate goal of advancing preclinical studies.

METHODS

KPC mice were created by breeding Kras^LSL-G12D/+ to Trp53^fl/fl;Ptf1α^Cre/+, resulting in Kras^LSL-G12D/+;p53^fl/+;Ptf1α^Cre/+ mice. At 14 weeks of age, mice were palpated for spontaneous tumor growth that was verified using ultrasounds. Mice with tumors under 15 mm in diameter were used. The mice were assigned to one of seven treatment regimens: 1 cycle of mFFX (FFX X1), 2 cycles of mFFX (FFX X2), 1 cycle of mFFXwith 40 Gy SBRT (FFX SBRT), 1 cycle of gemcitabine/nab-paclitaxel (GEM/AB X1), 2 cycles of gemcitabine/nab-paclitaxel (GEM/AB X2), 2 cycles of gemcitabine/nab-paclitaxel with 40 Gy SBRT (GEM/AB SBRT), or saline only (control).

RESULTS

In total, 92 mice were included. The median OS in the FFX X2 group was slightly longer that the median OS in the FFX X1 group (15 days vs 11 days, P = 0.003). Mice in the GEM/AB X2 group had longer OS when compared to mice in the GEM/AB X1 group (33.5 vs 13 days, P = 0.001). Mice treated with chemotherapy survived longer than untreated control animals (median OS: 6.5 days, P < 0.001). Moreover, in mice treated with chemotherapy, mice that received 2 cycles of GEM/AB X2 had the longest survival, while the FFX X1 group had the poorest OS (P < 0.001). The addition of chemotherapy was associated with reduced number of myeloid and lymphoid cell types, except for CD4 + cells whose levels were largely unaltered only in tumors treated with gemcitabine/nab-paclitaxel. Lastly, chemotherapy followed by consolidative SBRT trended towards increased local control and survival.

CONCLUSIONS

We demonstrate the utility and feasibility of clinically relevant mFOLFIRINOX and gemcitabine/nab-paclitaxel in preclinical models of pancreatic cancer.

“Super massive” intrahepatic cholangiocarcinoma: Potential role of radiation therapy

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Background: Intrahepatic cholangiocarcinoma (ICC) is a cancer of the bile ducts within the liver. Most patients have unresectable disease and die of tumor-related liver failure (TRLF); prior data suggest that radiation therapy (RT) may play an important role in decreasing TRLF and improving survival. However, for patients with exceptionally large liver tumors, the role of RT is uncertain. Here, we present our experience using hypofractionated RT for so-called “super-massive” ICC (gross tumor volume > 800cc). Methods: We retrospectively collected data from ICC patients treated at the University of Texas MD Anderson Cancer Center. We included inoperable patients (both M0 and M1) who were treated with RT, identified those with a gross tumor volume of 800cc or more (median: 1,300cc IQR: 900-1,900). We analyzed overall survival (OS), local and distant recurrence, tumor-related liver failure (TRLF), and treatment toxicity. Results: A total of 12 patients were included. The median age was 60 (IQR: 55-67). The average maximal tumor diameter was 14.1cm (IQR: 12.6-15.8). All but 1 patient received pre-RT systemic therapy. Eight patients (67%) were treated with IMRT, and 4 patients (33%) with proton RT. RT was delivered to a median of 67.5Gy (IQR: 60-73.1) over 15 fractions. At a median follow up of 17.4 months, 5 patients were still alive (2-year OS: 41.7%). Median OS, local recurrence, and distant metastasis from RT were 20.0, 20, and 11.3 months, respectively. Two patients (16.7%) died from TRLF. No grade 2 or higher toxicities were noted. No radiation-induced liver toxicity was present. Conclusions: Hypofractionated RT was safe and showed promising clinical outcomes for patients with “super massive” inoperable ICC, compared to historical data. Future studies are still needed to better assess the role of RT in this patient population.

Evaluation of Cardiotoxicity in HER-2-Positive Breast Cancer Patients Treated With Radiation Therapy and Trastuzumab

PURPOSE

Trastuzumab is associated with cardiac dysfunction in patients with human epidermal growth factor receptor 2 (HER-2)-positive breast cancer. The current study examines the effect of radiation therapy (RT) on cardiotoxicity in this patient population.

METHODS AND MATERIALS

The Herceptin Adjuvant (HERA) trial is a phase 3 prospective, randomized clinical trial that established the efficacy of trastuzumab in HER-2-positive breast cancer. The current study is a retrospective analysis of 3321 trial patients treated with trastuzumab, with or without RT. Cardiac function was closely monitored over a median follow-up period of 11 years. The primary endpoint of the current study was to determine the effect of RT on left ventricular ejection fraction (LVEF) and the occurrence of cardiovascular events.

RESULTS

Patients were divided into 3 groups: 1270 patients received trastuzumab and left-sided RT (group 1); 1271 patients received trastuzumab and right-sided RT (group 2); and 780 patients received trastuzumab with no RT (group 3). The incidence of decline in LVEF documented by echocardiography was 9.18%, 8.99%, and 8.80%, respectively, with no significant differences among the 3 groups (P = .073). The incidence of cardiovascular events was low in all groups, with the lowest incidence noted in group 3 (0.62%) followed by group 2 (0.92%) and group 1 (1.08%) (P = .619). Univariate and multivariate competing-risks regression showed that left-sided and right-sided RT delivery did not significantly increase the risk of LVEF decline or cardiovascular events.

CONCLUSIONS

Our analysis of the HERA trial suggests that RT does not significantly increase the risk of cardiotoxicity in HER-2-positive breast cancer patients treated with trastuzumab. Continued monitoring of patients is needed to investigate late effects of contemporary treatments for breast cancer patients.

Abstract PO-225: Patterns of colorectal cancer screening in the US: Analysis of the 2019 National Health Interview Survey

Introduction: Colorectal cancer (CRC) is the third most common cancer in the United States and, while there is growing conscience towards it, screening is still not widely adopted. Methodology: We used data from the 2019 National Health Interview Survey, which is a cross-sectional study that included 31,997 participants. We focused on the colorectal cancer screening module, and particularly on questions related to participants having ever had a colonoscopy (COL) or sigmoidoscopy (SIG). We then performed bivariate and multivariable analyses to assess the association between participants' variables and having had a COL or SIG. Results: In total, 22,025 participants answered the CRC screening module, and 13,383 participants (60.8%) had done a previous COL/SIG. Participants' sex was not associated with differences in the use of COL/SIG for CRC screening (OR=1.0, P=0.89). When assessing race, Hispanics (OR=0.9, P=0.03) and Asians (OR=0.7, P&lt;0.001) had less odds for undergoing COL or SIG compared to Whites. In the education scope, participants with a college degree (63.2%), some college (62.8%), and high school graduates (58.6%) had undergone more COL or SIG than those with no school or incomplete high school (52.2%). Participants born in the U.S. had more COL or SIG performed than those who were not born in the U.S. (63.6% vs. 45.5%, respectively, P&lt;0.05). Moreover, participants who do not have a usual place for healthcare underwent less COL/SIG for CRC screening (OR=0.3, P&lt;0.001). When assessing insurance, participants with a private or military health insurance were at higher odds for having a COL or SIG, as opposed to any public insurance or no insurance at all (OR=0.8, 0.4, respectively; P&lt;0.001 for both). On multivariable analysis, race, education, nativity in the U.S., insurance, and age were all independently associated with differences in the use of COL/SIG. Conclusions: Colonoscopy and sigmoidoscopy are widely used for CRC screening, however, differences in patterns of use still exist among various U.S. populations.

Citation Format: Humberto R. Nieves-Jimenez, Isabela M. Bumanlag, Joseph Abi Jaoude, Ethan B. Ludmir, Cullen M. Taniguchi. Patterns of colorectal cancer screening in the US: Analysis of the 2019 National Health Interview Survey [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-225.

Abstract PO-249: Prostate screening & patient knowledge on PSA testing among males: Analysis of the 2019 NHIS

Intro: Prostate cancer, one of the most common cancers for males, continues to have non-standardized screening with Prostate Specific Antigen (PSA) due to the potential risks and uncertainties that PSA screening can pose. Methods: The purpose of this study is to investigate the knowledge base of participants regarding the advantages and disadvantages of PSA screening. Using the 2019 National Health Interview Survey, we performed descriptive statistics on participant demographics and prostate screening questions. Bivariate and multivariable logistic regression was utilized to highlight variables that were associated with whether or not a doctor explained to a participant the advantages and disadvantages of PSA testing. Results: Overall, we gathered answers from 10,165 respondents aged 40 years or older, from a total of 31,997 participants in the 2019 NHIS survey. Nearly half of respondents (5004, 49.2%) reported that they had undergone a PSA test in the past and 38.6% of respondents reported that a doctor had discussed the advantages of a PSA test. On the other hand, only 25.8% reported that a doctor had discussed possible disadvantages of PSA testing. Our stratified analyses found that Asians were less likely to report that a doctor had discussed the advantages of a PSA test (OR = 0.59, P &lt; 0.05). We also found that the higher the educational status of a participant, the more likely a participant would report that a doctor talked about the advantages of a PSA test (high school graduates, OR = 1.83, P&lt;0.05; college degrees, OR = 2.48, P &lt; 0.05). Those without any form of health insurance coverage were less likely to be told about the advantages of PSA testing (OR = 0.60, P&lt; 0.05). Similar values in each of these covariates were also found to be statistically significant when participants were asked if a doctor had talked to them about the disadvantages of a PSA test. Conclusions: We found disparities of prostate cancer screening education based on social factors, which reinforce concerns of disparate access of information provided by physicians on the advantages and disadvantages of a PSA testing. Our findings support a call for the improvement of adequate patient-doctor discussions that fully address the risks and benefits of PSA testing.

Citation Format: Isabela M. Bumanlag, Humberto R. Nieves-Jimenez, Joseph Abi Jaoude, Ethan B. Ludmir, Cullen M. Taniguchi. Prostate screening & patient knowledge on PSA testing among males: Analysis of the 2019 NHIS [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-249.

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.

Stereotactic Versus Conventional Radiation Therapy for Patients With Pancreatic Cancer in the Modern Era

PURPOSE

Patients with pancreatic cancer often receive radiation therapy before undergoing surgical resection. We compared the clinical outcomes differences between stereotactic body radiation therapy (SBRT) and 3-dimensional (3D)/intensity-modulated radiation therapy (IMRT).

METHODS AND MATERIALS

We retrospectively collected data from the University of Texas MD Anderson Cancer Center. Patients with borderline resectable/potentially resectable or locally advanced pancreatic cancer receiving neoadjuvant SBRT (median, 36.0 Gy/5fx), 3D conformal radiation (median, 50.4 Gy/28 fx) or IMRT (median, 50.4 Gy/28 fx) were included. Overall survival (OS) and progression-free survival were analyzed using Cox regression.

RESULTS

In total, 104 patients were included in our study. Fifty-seven patients (54.8%) were treated with SBRT, and 47 patients (45.2%) were treated with 3D/IMRT. Patients in the SBRT group were slightly older (median age: 70.3 vs 62.7 in the 3D/IMRT group). Both groups had similar proportions of patients with locally advanced pancreatic cancer (SBRT: 30, 52.6%; 3D/IMRT: 24, 51.1%). All patients were treated with chemotherapy. Patients in the SBRT group underwent more surgical resection compared with the 3D/IMRT group (38.6% vs 23.4%, respectively). At a median follow-up of 22 months, a total of 60 patients (57.7%) died: 25 (25/57, 43.9%) in the SBRT group, and 35 (35/47, 74.5%) in the 3D/IMRT group. Median OS was slightly higher in the SBRT group (29.6 months vs 24.1 months in the 3D/IMRT group). On multivariable Cox regression, the choice of radiation therapy technique was not associated with differences in OS (adjusted hazard ratios [aHR] = 0.5; 95% confidence interval [CI], 0.2%-1.3%, P = .18). Moreover, patients that underwent surgical resection had better OS (aHR = 0.3, 95% CI, 0.1%-0.8%, P = .01). Furthermore, progression-free survival was also similar between patients treated with SBRT and those treated with 3D/IMRT (aHR = 0.9, 95% CI, 0.5%-1.8%, P = .81).

CONCLUSIONS

SBRT was associated with similar clinical outcomes compared with conventional radiation techniques, despite being delivered over a shorter period of time which would spare patients prolonged treatment burden. Future prospective data are still needed to better assess the role of SBRT in patients with pancreatic cancer.

Comparative Untargeted Metabolomic Profiling of Induced Mitochondrial Fusion in Pancreatic Cancer

Mitochondria are dynamic organelles that constantly alter their shape through the recruitment of specialized proteins, like mitofusin-2 (Mfn2) and dynamin-related protein 1 (Drp1). Mfn2 induces the fusion of nearby mitochondria, while Drp1 mediates mitochondrial fission. We previously found that the genetic or pharmacological activation of mitochondrial fusion was tumor suppressive against pancreatic ductal adenocarcinoma (PDAC) in several model systems. The mechanisms of how these different inducers of mitochondrial fusion reduce pancreatic cancer growth are still unknown. Here, we characterized and compared the metabolic reprogramming of these three independent methods of inducing mitochondrial fusion in KPC cells: overexpression of Mfn2, genetic editing of Drp1, or treatment with leflunomide. We identified significantly altered metabolites via robust, orthogonal statistical analyses and found that mitochondrial fusion consistently produces alterations in the metabolism of amino acids. Our unbiased methodology revealed that metabolic perturbations were similar across all these methods of inducing mitochondrial fusion, proposing a common pathway for metabolic targeting with other drugs.

Post-mastectomy Radiation Therapy in Triple-Negative Breast Cancer Patients: Analysis of the BEATRICE Trial

PURPOSE

Post-mastectomy radiation therapy (PMRT) improves locoregional control and overall survival in patients with breast cancer. With the evolution of systemic therapy, the benefit of PMRT in patients with triple-negative disease requires further evaluation.

PATIENTS AND METHODS

BEATRICE is a phase III randomized clinical trial that examined the efficacy of bevacizumab in patients with triple-negative breast cancer (TNBC). The current study is a retrospective analysis of data on patients enrolled and treated with mastectomy and systemic therapy. The primary endpoint was determining the effect of PMRT on locoregional recurrence rates (LRR). Hazard ratios were estimated using Cox regression, and LRR curves were generated by the Kaplan-Meier method.

RESULTS

In total, 940 patients were included in our analysis, of whom 359 (38.2%) received PMRT while 581 (61.8%) did not. At median follow-up of 5 years, no significant difference in LRR was noted between the PMRT and no PMRT groups in node-negative patients (HR = 1.09). Patients with N1 disease had 5-year LRR-free survival of 96% for PMRT versus 91% for no PMRT (HR = 0.46). Most N2 patients received PMRT and had 5-year LRR-free survival of 76%.

CONCLUSION

PMRT benefit in TNBC patients treated with modern systemic therapy is lower than historical reports. Delivery of PMRT in patients with N1 disease enrolled in the BEATRICE trial was not shown to improve local control. As this might be due to patient selection for PMRT, future randomized controlled trials are required to assess the role of PMRT in this patient population.

ADAM10 Evens Out the Double-Edged Sword of Radiotherapy in Pancreatic Cancer

Radiotherapy plays an important role in the management of pancreatic ductal adenocarcinoma (PDAC), especially when patients are not surgical candidates. Radiation-induced tumor death provokes an acute inflammation followed by a late-fibrotic response that parallels the fibroinflammatory tumor microenvironment of PDAC, inciting the question of whether radiation-induced fibrosis contributes to PDAC progression. The study published in this issue by Mueller and colleagues presents a potential mechanism linking radiation-induced fibrosis with expression of a disintegrin and metalloprotease 10 (ADAM10) and ephrinB2, which may also contribute to tumor progression. The authors show that ablation of ADAM10 decreases radiation-induced fibrosis and improves survival in preclinical models. These data suggest that targeting ADAM10 may help to improve clinical outcomes with radiotherapy, particularly if definitive radiation is not possible. A better understanding of the biology of radiotherapy in pancreatic cancer remains crucial, and Mueller and colleagues offer important insight in this regard.See related article by Mueller et al., p. 3255.

Lack of pre-planned financial outcomes evaluation in phase 3 cancer trials

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Background: New cancer treatments have the potential to cause economic stress at the personal and societal level. Little is known on the evaluation of financial outcomes in clinical trials. We hypothesized that randomized controlled trials (RCTs) are unlikely to have pre-planned analyses to look at economic outcomes that address financial toxicity to patients and cost-effectiveness to society. Methods: Interventional therapeutic-intent phase 3 cancer-specific RCTs were identified through ClinicalTrials.gov. Pre-planned economic outcomes addressing financial toxicity or cost-effectiveness were identified. Results: We identified 1,069 interventional phase 3 oncology RCTs. Overall, 101 (9.4%) had pre-planned to evaluate quality of life using the European Organization for Research and Treatment of Cancer Quality of Life (QOL) Questionnaire (EORTC QLQ-C30) instrument, of which a single question (Q28) relates to financial toxicity. However, only ten (0.94%) trials included pre-planned financial/economic endpoints; all were secondary endpoints. Among those planning to evaluate economic outcomes, 6/10 planned to collect data and report on financial distress using Q28 on EORTC QLQ-C30 and 3/10 pre-planned performing cost-effectiveness analyses. One study planned to perform an economic evaluation, including health utilities, as measured by the EuroQol-Five Dimension (EQ-5D) Questionnaire. All ten trials were industry–sponsored, and two were co-sponsored by a National Cancer Institute (NCI) cooperative group. The majority (8/10) were superiority-designed trials, and 6/10 included progression-free survival as the primary endpoint. The majority (6/10) assessed targeted therapy as the primary intervention. Multinational enrollment was predominant (8/10). Of the 10 trials, nine had a published manuscript. One was closed because of accrual issues. Among the six trials that had pre-specified reporting on financial distress, two published on financial toxicity. Of the two trials that had a priori planned to do a cost-effective analysis, one was published. However, overall 3/9 had published a cost-effective analysis. Conclusions: Less than one percent of oncology RCTs have pre-specified plans to evaluate economic outcomes associated with personal financial distress or cost-effectiveness. For the trials that had pre-planned reporting on financial toxicity, the instrument used to evaluate financial toxicity is a single question which has not been validated as a standalone assessment. Cost-effectiveness analyses were more likely to be published than on financial toxicity and were often completed as a post-hoc analysis. Given that many newly investigated therapies increase the financial burden on patients and add cost to the healthcare system more broadly, pre-planned evaluation of economic outcomes in RCTs is imperative in order to create a value-based framework in assessing new therapies.

Association of the anorectal microbiome and patient-reported gastrointestinal outcomes in patients with anal cancer

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Background: Among patients with anal cancer undergoing chemoradiotherapy, the association between the microbiome and toxicity is not well documented. We sought to quantify the gastrointestinal-related patient-reported outcomes (PROs) and local microbiome profiles of patients with anal cancer receiving chemoradiotherapy in order to check for potential profiles that can help in predicting toxicity during treatment. Methods: We prospectively followed patients with non-metastatic squamous cell carcinoma of the anal canal who received definitive chemoradiotherapy. Anorectal swab samples were collected before treatment initiation and at 4 subsequent timepoints. Consequently, PROs were collected using the bowel subdomain of the Expanded Prostate Cancer Index Composite (EPIC). Samples were sequenced using 16S rRNA of the V4 region. Sequence reads were grouped by amplicon sequence variants (ASV’s) representative of unique bacterial species. We then used Linear discriminant analysis Effect Size (LEfSe) with an effect size of 4 to identify taxa at baseline that were differentially enriched in patients with high vs. low toxicity by end of treatment. We compared the EPIC scores with the relative abundance of species identified in the LEfSe using a paired Wilcoxon test. Results: The study included 22 patients (18 women and 4 men), whose median age was 59 years. Most patients were Stage III (59%) with negative HIV status (94%). The majority of patients (91%) received standard of care chemoradiotherapy. Overall toxicity was the highest at week 5 of treatment. At all individual time points, alpha diversity of the microbiome did not correlate with patient-reported GI function, additionally overall baseline diversity was not predictive of eventual GI outcomes. The LEfSe identified that patients with low patient reported toxicity at week 5 had higher of abundance of Selenomonas at baseline, while patients with higher toxicity had high abundance of baseline Actinobacteria, Peptoniphilus, Clostridiales , and Clostridia. When comparing the relative abundance of bacterial species among patients with high and low toxicities, patients with higher relative abundance of Clostridia and Actinobacteria had significantly higher toxicity (p = 0.03). Conclusions: Certain microbiome profiles at baseline are associated with anal cancer patients’ gastrointestinal-related PROs during chemoradiation. Our data provide novel avenues to study the potential uses of the local microbiome as a biomarker in predicting treatment toxicities in anal cancer.

EUS-guided placement of fiducial markers for image-guided radiotherapy in gastrointestinal tumors: A critical appraisal

We present here a new chapter of the series of papers on how to perform specific EUS techniques. In this manuscript, we discuss on how to perform EUS-guided placement of fiducial markers in gastrointestinal tumors. The aim is to present the scientific evidence of fiducials placement before radiation therapy, including an accurate revision of the literature, to give some advices on the technical approach, and to discuss Pros and Cons from the point of view of gastroenterologists and radiation oncologist.

Post-lumpectomy radiation therapy boost in breast cancer patients: evidence revisited

Purpose

Radiation therapy is an integral part in the management of breast cancer after breast conservative surgery. In selected patients at high risk for local recurrence (LR), a boost radiation dose is commonly applied to the tumour bed.

Methods

We performed a review of the English literature using PubMed, Medline and Google Scholar for published manuscripts addressing the effect of boost radiation in breast cancer patients, focusing mainly on LR and overall survival (OS).

Results

A total of seven studies were included in our review. Most studies (6/7, 85.7%) showed a significant improvement in local control independent of age (hazard ratios ranging between 0.34 and 0.73), with the largest absolute benefit in younger patients. None of the studies, however, was able to demonstrate an improvement in OS.

Conclusions

With lack of sufficient studies addressing the role of boost radiation, individualised treatment decisions are recommended, taking into account the risk factors for LR, including tumour biology. Real-life data are sorely needed to better assess the role of tumour bed boost in the contemporary era.

Impact of Fiducial Marker Placement Before Stereotactic Body Radiation Therapy on Clinical Outcomes in Patients With Pancreatic Cancer

Purpose

Localized pancreatic cancer is commonly treated with stereotactic body radiation therapy (SBRT), which often requires the placement of fiducial markers. We compared the clinical outcomes of patients with and without fiducial markers.

Methods and Materials

We retrospectively collected data on patients with pancreatic cancer treated with neoadjuvant SBRT at a single institution. Patients were divided into 2 groups based on the placement of a fiducial marker. Local recurrence was the primary outcome. Time to event endpoints were analyzed using COX regression.

Results

We included 96 patients with unresectable pancreatic cancer: 46 patients (47.9%) did not have a fiducial marker, and 50 patients (52.1%) had a fiducial placed. Patients in the fiducial group were older and had more locally advanced pancreatic cancer compared with those who did not have a fiducial placed. Most patients in both groups (92.7%) received chemotherapy before SBRT treatment. SBRT was delivered to a median of 36 Gy over 5 fractions in the no-fiducial group, and 38 Gy over 5 fractions in the fiducial group. At a median follow-up of 20 months, local recurrence was similar irrespective of fiducial placement (adjusted hazard ratio [aHR] 0.6, 95% CI 0.3-1.3, P = .59). Furthermore, no difference in overall survival was noted between the 2 groups (aHR 0.8, 95% CI 0.3-1.9, P = .65). In patients who eventually underwent surgery post-SBRT, no difference in surgical margins (P = .40) or lymphovascular invasion (P = .76) was noted between the 2 groups. No patient developed acute pancreatitis after fiducial placement.

Conclusions

Our data suggest that the use of fiducial markers does not negatively affect clinical outcomes in patients with localized pancreatic cancer. Prospective confirmation of our results is still needed.

Performance Status Restriction in Phase III Cancer Clinical Trials

BACKGROUND

Patients with good performance status (PS) tend to be favored in randomized clinical trials (RCTs), possibly limiting the generalizability of trial findings. We aimed to characterize trial-related factors associated with the use of PS eligibility criteria and analyze patient accrual breakdown by PS.

METHODS

Adult, therapeutic, multiarm phase III cancer-specific RCTs were identified through ClinicalTrials.gov. PS data were extracted from articles. Trials with a PS restriction ECOG score ≤1 were identified. Factors associated with PS restriction were determined, and the use of PS restrictions was analyzed over time.

RESULTS

In total, 600 trials were included and 238,213 patients had PS data. Of those trials, 527 studies (87.8%) specified a PS restriction cutoff, with 237 (39.5%) having a strict inclusion criterion (ECOG PS ≤1). Enrollment criteria restrictions based on PS (ECOG PS ≤1) were more common among industry-supported trials (P<.001) and lung cancer trials (P<.001). Nearly half of trials that led to FDA approval included strict PS restrictions. Most patients enrolled across all trials had an ECOG PS of 0 to 1 (96.3%). Even among trials that allowed patients with ECOG PS ≥2, only 8.1% of those enrolled had a poor PS. Trials of lung, breast, gastrointestinal, and genitourinary cancers all included <5% of patients with poor PS. Finally, only 4.7% of patients enrolled in trials that led to subsequent FDA approval had poor PS.

CONCLUSIONS

Use of PS restrictions in oncologic RCTs is pervasive, and exceedingly few patients with poor PS are enrolled. The selective accrual of healthier patients has the potential to severely limit and bias trial results. Future trials should consider a wider cancer population with close toxicity monitoring to ensure the generalizability of results while maintaining patient safety.

Professional Medical Writer Assistance in Oncology Clinical Trials

Background

The use of professional medical writers (PMWs) has been historically low, but contemporary data regarding PMW usage are scarce. In this study, we sought to quantify PMW use in oncologic phase III randomized controlled trials (RCTs).

Methods

We performed a database query through ClinicalTrials.gov to identify cancer‐specific phase III RCTs; we then identified whether a PMW was involved in writing the associated trial manuscript reporting primary endpoint results.

Results

Two‐hundred sixty trials of 600 (43.3%) used a PMW. Industry‐funded trials used PMWs more often than nonindustry trials (54.9% vs. 3.0%, p < .001). Increased PMW usage was further noted among trials meeting their primary endpoint (53.4% vs. 32.9%, p < .001) and trials that led to subsequent Food and Drug Administration approval (63.1% vs. 36.3%, p < .001). By treatment interventions, PMW use was highest among systemic therapy trials (50.2%). Lastly, the use of PMWs increased significantly over time (odds ratio: 1.11/year, p = .001).

Conclusion

PMW use rates are high among industry‐funded trials. We urge continued and increased transparency in reporting the funding and use of PMWs.

Considering the increase in industry‐sponsored cancer clinical trials, the use of professional medical writers for publication of trial results has become an increasingly important topic. This brief communication reports the current rate of involvement of medical writers in publications of cancer clinical trials.

Lebanese Healthcare System: How Will the Aftermath Look?

The recent Lebanese port explosion came as a continuation of a series of socioeconomic disasters the country has been facing during the past year. In addition, the massive impact of the coronavirus disease-19 (COVID-19) pandemic further hastened the collapse of the Lebanese healthcare system. In light of all those events, the Lebanese healthcare sector has faced major blows that will be difficult to recuperate from. In the aftermath of the Beirut port explosion, Lebanon received immense financial and medical support from the international community in a timely fashion, which secured first level care to victims of the explosion. Nevertheless, this forced Lebanon, which was considered a prominent tertiary medical hub in the Middle East, to slowly regress into an exclusive primary care provider. As such, it is crucial for local and regional stakeholders to build strong collaborations, and shape a unified vision of Lebanon's future healthcare system.

De-intensifying Radiation Therapy in HER-2 Positive Breast Cancer: To Boost or Not to Boost?

PURPOSE

Radiation therapy is fundamental in the management of breast cancer. After whole breast irradiation, an additional boost dose is often applied to the primary tumor bed. Here, we analyze the effect of radiation therapy boost on local control in patients with HER-2 positive breast cancer.

METHODS AND MATERIALS

We studied 1082 patients with HER-2 positive breast cancer who were originally enrolled in the Herceptin Adjuvant Trial and treated with breast-conserving surgery, radiation therapy, and adjuvant chemotherapy with trastuzumab. The primary endpoint of the study was to determine the effect of a radiation boost on local recurrence. Kaplan-Meier curves were generated, and hazard ratios were estimated using Cox regression.

RESULTS

Our analysis included 441 patients (40.8%) who received radiation therapy boost and 641 patients (59.2%) who did not, after completion of whole breast radiation. Patients from both groups had similar baseline characteristics in terms of age, nodal involvement, and grade. At a median follow-up of 11 years, local control was 93% (confidence interval, 90%-95%) in the radiation boost group compared with 91% (confidence interval, 89%-93%) in the no-boost group (P = .33). When analyzing patients by age, patients <40 years of age had a higher risk for local recurrence; however, this was not significantly lowered by the addition of boost. Furthermore, no local control benefit for boost was noted in both hormone receptor (HR) subtypes (HR+: P = .11; HR-: P = .98).

CONCLUSIONS

Patients with HER-2 positive breast cancer treated with breast-conserving surgery, whole breast radiation, and trastuzumab have excellent local control. Delivery of an additional radiation boost in this patient population was not shown to improve local control. Future studies are needed to identify subgroups of HER-2 positive patients who derive a clinically relevant benefit from radiation boost.

Patient-Reported GI Outcomes in Patients With Anal Cancer Receiving Modern Chemoradiation

PURPOSE

Among patients with anal cancer, chemoradiotherapy is often associated with toxicities that diminish quality of life. We describe the GI-related patient-reported outcomes (PROs) of patients with anal cancer receiving chemoradiotherapy to improve patient-physician communication.

METHODS

We prospectively followed patients with nonmetastatic squamous cell carcinoma of the anal canal who received definitive chemoradiotherapy. Patients completed the bowel subdomain of the Expanded Prostate Cancer Index Composite (EPIC) questionnaire before treatment and at 4 subsequent timepoints. We used the paired Wilcoxon test to compare EPIC scores at different times.

RESULTS

The study included 21 patients; median age was 57 years. Most patients (52%) had T2 and either N0 or N1 disease (81%). Most patients (91%) received chemotherapy with cisplatin-fluorouracil and either intensity-modulated radiotherapy or volumetric modulated arc therapy. Compared with the patients' median overall summary score at baseline (66), their median score at 1 week (82) was higher (P = .009), whereas their median score at 5 weeks (54) was lower (P = .025). The patients' median overall summary score at baseline and at 3 months did not differ (P = .919). Three months after radiotherapy, most patients reported minimal adverse effects compared with baseline.

CONCLUSION

The GI-related PROs of patients with anal cancer tend to fluctuate during radiotherapy but return to baseline by 3 months, at which time most patients report few or no residual adverse effects. We provide a clear timeline of GI acute toxicity using sequential PRO measurements that will improve patient-physician communication regarding expectations for cancer treatment.

Characteristics of the Multiplicity of Randomized Clinical Trials for Coronavirus Disease 2019 Launched During the Pandemic

This systematic review examines current randomized clinical trials of therapeutic agents to treat coronavirus disease 2019 (COVID-19).

Evolving role of biomaterials in diagnostic and therapeutic radiation oncology

Radiation therapy to treat cancer has evolved significantly since the discovery of x-rays. Yet, radiation therapy still has room for improvement in reducing side effects and improving control of cancer. Safer and more effective delivery of radiation has led us to novel techniques and use of biomaterials. Biomaterials in combination with radiation and chemotherapy have started to appear in pre-clinical explorations and clinical applications, with many more on the horizon. Biomaterials have revolutionized the field of diagnostic imaging, and now are being cultivated into the field of theranostics, combination therapy, and tissue protection. This review summarizes recent development of biomaterials in radiation therapy in several application areas.

Radiation therapy for patients with locally advanced pancreatic cancer: Evolving techniques and treatment strategies

Despite ongoing efforts, patients with locally advanced pancreatic cancer (LAPC) continue to have a dismal prognosis. Such tumors are unresectable, and optimal treatment with chemotherapy and/or radiation therapy is still not established. While chemotherapy is conventionally aimed at preventing metastatic spread of disease, radiation therapy acts locally, improving local control which can potentially improve overall survival and most importantly quality of life. Here, we aim to review the primary literature assessing the role of diverse radiation therapy strategies for patients with LAPC. Many radiation regimens can be considered, and no standard treatment has demonstrated a clear improvement in clinical outcomes. We advise that the modality of choice be dependent on the availability of equipment, the dose and fractionation of treatment, as well as the dose received by normal tissue. Moreover, a candid discussion with the patient concerning treatment goals is equally as essential. Three notable strategies for LAPC are intensity-modulated radiation therapy, volumetric modulated arc therapy, and proton. These radiation modalities tend to have improved dose distribution to the target volumes, while minimizing the radiation dose to surrounding normal tissues. Stereotactic body radiation therapy can also be considered in LAPC patients in cases where the tumor does not invade the duodenum or other neighboring structures. Because of the high doses delivered by stereotactic body radiation therapy, proper respiratory and tumor motion management should be implemented to reduce collateral radiation dosing. Despite improved clinical outcomes with modern radiation modalities, evolving techniques, and more accurate planning, future studies remain essential to elucidate the optimal role for radiation therapy among patients with LAPC.

The landscape of gastrointestinal oncologic phase III clinical trials in the last two decades

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Background: Gastrointestinal (GI) cancers are among the most common cancers in adult patients. The prognosis of GI cancers differs widely between specific subsites, with some cancers having excellent prognoses, and others (such as pancreatic and hepatobiliary cancers) having an extremely poor prognosis. We sought to characterize the landscape of GI oncologic clinical trials in the last two decades. Methods: We searched ClinicalTrials.gov for phase III RCTs between 2003 and 2018. Randomized multi-arm trials assessing a therapeutic intervention in adult cancer patients were included. GI cancer trials were identified and grouped into specific disease subsites. Differences in trial factors between GI and non-GI trials and between different GI subsites were analyzed. Results: Out of the 600 RCTs identified, 76 trials assessed gastrointestinal cancers (12.7%). By disease subsite, we identified 21 (27.6%) gastro-esophageal cancer trials, 12 (15.8%) pancreatic cancer trials, 11 (14.5%) hepatobiliary cancer trials, and 32 (42.1%) colorectal cancer trials. GI cancer trials were more likely to be industry funded when compared to non-GI cancer trials (88.2% vs 76.3% respectively, p = 0.02). Furthermore, only 18.4% of GI trials had cooperative group sponsorship (vs 33.3% for non-GI trials, p = 0.01). Most GI cancer trials assessed systemic therapy interventions (85.5%); only 6 trials (7.9%) addressed supportive care interventions (vs 20.2% for non-GI trials, p = 0.01). Around half of GI cancer trials (51.3%) met their primary endpoints, but only 8 trials (10.5%) led to subsequent FDA approval. All FDA approvals were for colorectal cancer treatments, and none for gastroesophageal, pancreatic or hepatobiliary cancers (p = 0.01). Most patients (97.1%) accrued on GI cancer trials had a good performance status (Eastern Cooperative Oncology Group of 0 to 1). Specifically, 95.9% of patients in pancreatic trials and 98.6% of patients in hepatobiliary trials had a good performance status. Conclusions: While many GI cancers have a poor prognosis, very few trials assess supportive care interventions in this populations. Moreover, most patients included in GI cancer trials have a good performance status. In that regard, future GI cancer trials addressing supportive care measures with a wider cancer population are still warranted.

Performance status restriction in phase III cancer clinical trials

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Background: Patients with good performance status (PS) tend to be favored in randomized clinical trials (RCTs), possibly limiting the generalizability of trial findings. We sought to characterize trial-related factors associated with the use of eligibility criteria that restrict patients by PS, and analyze patient accrual breakdown by PS. Methods: We searched ClinicalTrials.gov for phase III RCTs between 2003-2018. Randomized multi-arm trials assessing a therapeutic intervention in cancer patients were included. PS data were extracted from corresponding manuscripts. Trials with PS restriction Eastern Cooperative Oncology Group (ECOG) ≤1 were identified. Factors associated with PS restriction were determined, and trial patient accrual was analyzed. Results: Six-hundred trials were included with PS data for 238,213 patients. In total, 527 studies (87.8%) specified an upper PS restriction cutoff as part of their exclusion criteria, and 237 studies (39.5%) had a strict inclusion criterion of patients with ECOG PS ≤1. Enrollment criteria restrictions based on PS (ECOG PS ≤1) were more common among industry-supported trials (P< 0.001) and lung cancer trials (P < 0.001). Nearly half of trials that led to subsequent FDA approval included strict PS restrictions. Binary logistic regression revealed stable use of restrictive PS eligibility criteria between 2007-2018 (P= 0.789). The vast majority of patients enrolled across all trials had an ECOG PS of 0 to 1 (96.3%). Even among trials that allowed patients with ECOG PS ≥2, only 8.1% of enrolled patients had a poor PS (ECOG 2 or higher).Trials of hematologic cancers had the largest proportion of patients with ECOG PS ≥2 (8.7%), while lung, breast, gastrointestinal and genitourinary trials all included less than 5% of patients with poor PS (P< 0.001). Only 4.8% of patients enrolled in trials that led to subsequent FDA approval had a poor PS. Conclusions: The use of PS restrictions in oncologic RCTs is pervasive, and exceedingly few patients with poor PS are enrolled. The selective accrual of healthier patients has the potential to severely limit and bias trial results. Future trials should consider a wider cancer population with close toxicity monitoring, to ensure generalizability of results, while maintaining patient safety.

Patient-reported gastrointestinal outcomes in patients with anal cancer

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Background: Among patients with anal cancer, chemoradiotherapy tends to offer an excellent prognosis but is often associated with undesirable toxicities that diminish quality of life. We sought to quantify the gastrointestinal-related patient-reported outcomes (PROs) of anal cancer patients receiving chemoradiotherapy in order to improve patient-physician communication and shared decision making. Methods: We prospectively followed patients with non-metastatic squamous cell carcinoma of the anal canal who received definitive chemoradiotherapy. Patients reported outcomes were collected using the bowel subdomain of the Expanded Prostate Cancer Index Composite (EPIC) questionnaire before treatment and at 4 subsequent timepoints. We used descriptive statistics to summarize the patients’ characteristics and EPIC scores, then used the paired Wilcoxon test to compare EPIC scores at different timepoints. Results: The study included 21 patients (16 women and 5 men), whose median age was 57 years. Most patients (52%) had T2, and either N0 (38%) or N1 (43%) disease. Most patients (91%) received standard of care chemoradiotherapy. Compared with the patients’ median overall summary score at baseline (66), their median score at 1 week (82) was significantly higher (p = 0.009), whereas their median score at 5 weeks (54) was significantly lower (p = 0.025). However, the patients’ median overall summary score at baseline and at 3 months did not differ significantly (p = 0.919). Three months after radiotherapy, most patients (73%) reported rarely or never having bloody stools, and most (82%) reported rarely or never being bothered by bloody stools. Overall, EPIC scores show initial improvement of all domains, followed by some worsening of symptoms before returning to baseline levels. Conclusions: Anal cancer patients’ gastrointestinal-related PROs tend to fluctuate during radiotherapy but return to baseline by 3 months, at which time most patients report few or no residual side effects. Our data provide a clear timeline of gastrointestinal acute toxicity using sequential PRO measurements that will improve patient-physician communication regarding expectations for cancer treatment and help in shared decision making.

Professional medical writing assistance in oncology clinical trials

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Background: Academic publishing remains the cornerstone of biomedical research and scientific communication. Researchers often assign professional medical writers (PMWs) to craft publications, as these individuals may improve the overall writing quality and/or reduce time to publication. We sought to characterize the landscape of PMW utilization in phase III cancer clinical trials. Methods: We searched ClinicalTrials.gov for phase III randomized clinical trials between the years 2003 and 2018. Randomized multi-arm trials assessing a therapeutic intervention in cancer patients were included. After identifying the corresponding publications, we identified whether a PMW was involved in writing the manuscript based on author disclosures, along with any related funding information. Results: Six-hundred oncology RCTs with corresponding manuscripts were identified. In total, 260 (43.3%) trials used a PMW. Financial support to medical writers was largely provided by the industry (247/260, 95.0%). In multivariate analyses, PMW utilization was higher among industry-funded trials compared to non-industry-funded trials (OR: 14.2, p= 0.001). PMWs were used more frequently to report successful trials that met their primary endpoint (OR: 1.8, p= 0.03) but did not differ between English-speaking and non-English-speaking countries ( p= 0.19). Cooperative group trials used PMWs with less frequency compared to non-cooperative groups (OR 0.68, p < 0.001). PMWs were used more often in trials that led to subsequent drug FDA approval (69.6% vs 40.6% in trials that did not lead to subsequent FDA approval), but this association did not reach statistical significance in multivariate analysis ( p = 0.744). The use of PMWs has increased significantly over time (OR: 1.11/year, p =0.001). Conclusions: In this analysis, we show a strikingly high prevalence of PMW utilization in phase III oncology trials, with a vast majority of industry-supported studies using PMWs. We believe that professional writing assistance plays an important role in clear and efficient scientific communication. However, the disproportionate role of PMWs in reporting positive, industry-funded trials may represent a conflict of interest. We urge continued and increased reporting of utilization and funding of professional writing assistance in cancer clinical trials.