Ionescu, Ruxandra

Abstract Background Female underrepresentation in oncology clinical trials can result in outcome disparities. We evaluated female participant representation in US oncology trials by intervention type, cancer site, and funding. Materials and Methods Data were extracted from the publicly available Aggregate Analysis of ClinicalTrials.gov database. Initially, 270,172 studies were identified. Following the exclusion of trials using Medical Subject Heading terms, manual review, those with incomplete status, non-US location, sex-specific organ cancers, or lacking participant sex data, 1650 trials consisting of 240,776 participants remained. The primary outcome was participation to prevalence ratio (PPR): percent females among trial participants divided by percent females in the disease population per US Surveillance, Epidemiology, and End Results Program data. PPRs of 0.8-1.2 reflect proportional female representation. Results Females represented 46.9% of participants (95% CI, 45.4-48.4); mean PPR for all trials was 0.912. Females were underrepresented in surgical (PPR 0.74) and other invasive (PPR 0.69) oncology trials. Among cancer sites, females were underrepresented in bladder (odds ratio [OR] 0.48, 95% CI 0.26-0.91, P = .02), head/neck (OR 0.44, 95% CI 0.29-0.68, P < .01), stomach (OR 0.40, 95% CI 0.23-0.70, P < .01), and esophageal (OR 0.40 95% CI 0.22-0.74, P < .01) trials. Hematologic (OR 1.78, 95% CI 1.09-1.82, P < .01) and pancreatic (OR 2.18, 95% CI 1.46-3.26, P < .01) trials had higher odds of proportional female representation. Industry-funded trials had greater odds of proportional female representation (OR 1.41, 95% CI 1.09-1.82, P = .01) than US government and academic-funded trials. Conclusions Stakeholders should look to hematologic, pancreatic, and industry-funded cancer trials as exemplars of female participant representation and consider female representation when interpreting trial results.

1561 Background: Surgical interventions are studied less often than medical or radiation interventions in oncology clinical trials. We characterized surgical oncology trials registered on ClinicalTrials.gov, analyzed funding sources and identified features associated with early discontinuation and results reporting. Methods: We employed a cross-sectional study design with descriptive, logistic regression, cox regression, time series and survival analyses. We downloaded all 270,172 studies registered on the Aggregate Analysis of the ClinicalTrials.gov database from October 1, 2008 to March 9, 2020. After excluding non-interventional trials, applying cancer/oncology specific Medical Subject Heading terms to the remaining trials and excluding phase 1 trials, 27,915 trials were identified for manual review. Primary exposure variables were trial focus: neoplasia site and treatment modality (surgical interventions included investigations of outcomes from surgical resection or intra-operative/peri-operative changes), and funding: industry, U.S. government, academic. Results: 26,815 trials were found to have true oncology content; 1,661 (6.2%) involved surgical oncology, representing 311,789 patients. Funding sources were: 82.7% by academic institutions, 10.9% by industry, and 6.2% by U.S. government. The most studied neoplasia sites were colorectal (17.4% of trials), breast (10.7%), gastric (10.5%), hepatic (8.6%), lung (7.5%), brain/CNS (6.7%) and cervical (6.6%). U.S. government funded surgical oncology trials had the lowest risk of early discontinuation (adjusted HR 0.50, 95% CI: 0.26-0.99, p<0.047) and the highest odds of results reporting (adjusted OR 1.08, 95% CI: 0.55-2.11, p=0.83) (Table 1). Conclusions: There is a paucity of surgical oncology clinical trials compared to other treatment modalities, especially in context of surgery’s role in overall cancer care. From 2008-2020 only 6.2% of trials focused on surgical oncology, and U.S. government funded trials displayed the lowest hazard of early discontinuation and highest odds of results reporting. Stakeholders should look to government funded trials as models of improvement, but must increase representation and results dissemination of surgical oncology trials to guide treatment recommendations. Surgical oncology trial features and associated early discontinuation/results reporting. [Table: see text]