Evolving Trends in Latin American Participation in Global Oncology Clinical Trials: A Decade of Phase III Activity (2013-2022)

PURPOSE Latin America (LATAM), home to over 650 million people, remains under-represented in global oncology trials despite a growing cancer burden. This study aimed to evaluate the evolution of LATAM participation in phase III oncology trials over the past decade, with a focus on site distribution, cancer types studied, therapeutic classes investigated, and demographic reporting. METHODS We conducted a cross-sectional analysis of global phase III oncology trials registered on ClinicalTrials.gov between January 1, 2013, and December 31, 2022. Trials were included if they studied anticancer therapies and listed at least one LATAM site. We extracted data on trial geography, cancer type, treatment modality, control group, and Hispanic ethnicity reporting. Trends in proportional regional site representation and therapy class were assessed using the Mann-Kendall trend test. RESULTS A total of 172 phase III trials with LATAM sites were identified, representing 2,609 of 29,718 global sites (8.8%). Brazil (45.8%), Argentina (18.6%), and Mexico (13.0%) accounted for over 75% of LATAM trial sites. LATAM's proportional site representation increased modestly from 7.1% in 2013 to 9.3% in 2021 (Bonferroni-adjusted P = .040), but no individual country showed a statistically significant increase. The most frequently studied cancers were lung (26.7%), breast (22.1%), and genitourinary (16.3%). Targeted therapies (42.4%) and immunotherapies (33.1%) dominated, whereas hormone therapy declined over time. Hispanic ethnicity was reported in only 61.6% of trials, with no improvement over time. CONCLUSION Although LATAM's participation in global oncology trials has increased, it remains geographically concentrated and demographically under-reported. Structural and policy efforts are needed to improve trial equity and align research with regional cancer burdens.