Comparative Age-Based Prospective Multi-Institutional Observations of 12,367 Patients Enrolled to the American College of Surgeons Oncology Group (ACOSOG) Z901101 Trials (Alliance)

Background: The risk of surgery, particularly for older cancer patients with serious, extensive comorbidities, can make this otherwise curative modality precarious. Leveraging data from the American College of Surgeons Oncology Group, this study sought to characterize age-based comparative demographics, adverse event rates, and study completion rates to define how best to conduct research in older cancer patients. Methods: This study relied on clinical data from 21 completed studies to assess whether older patients experienced more grade 3 or worse adverse events and were more likely to discontinue study participation prematurely than their younger counterparts. Results: The study enrolled 12,367 patients. The median age was 60 years, and 36% of the patients were 65 years of age or older. Among 4008 patients with adverse event data, 1067 (27%) had experienced a grade 3 or worse event. The patients 65 years or older had higher rates of grade 3 or worse adverse events compared to younger patients [32% vs. 24%; odds ratio (OR), 1.5; 95% confidence interval (CI), 1.3–1.7; p < 0.0001]. This association was not observed in multivariate analyses. The study protocol was completed by 97% of the patients. No association was observed between age and trial completion (OR 0.8; 95% CI 0.7–1.1; p = 0.14). Only the older gastrointestinal cancer trial patients were less likely to complete their studies compared to younger patients (OR 0.50; 95% CI 0.30–0.70; p < 0.0001). Conclusion: Despite higher rates of adverse events, the older patients typically completed the study protocol, thereby contributing relevant data on how best to render care to older cancer patients and affirming the important role of enrolling these patients to surgical trials.