Clinical outcomes in elderly patients with metastatic colorectal cancer receiving bevacizumab and chemotherapy: Results from the BRiTE observational cohort study

Background: Elderly patients are underrepresented in clinical trials and frequently undertreated with standard therapy. The BRiTE observational cohort study assessed the safety and effectiveness of bevacizumab-based first-line therapy for metastatic colorectal cancer among a large cohort of elderly patients (896 patients ≥65 years, among 1,953 total patients). Methods: Treatment patterns, safety, progression-free survival (PFS), overall survival (OS) and survival beyond first progression (SBP) were analyzed by age cohorts. OS and SBP were further analyzed using Cox proportional hazards regression. Results: Median PFS (months) was similar across age cohorts (<65 years, 9.8; 65 to <75, 9.6; 75 to <80, 10.0; ≥80, 8.6). Median OS (months) decreased with age (<65 years, 26.0; 65 to <75, 21.1; 75 to <80, 20.3; ≥80, 16.2). SBP declined with age; however, a Cox model adjusting for baseline and postbaseline covariates that were imbalanced among age cohorts showed a reduced independent effect of age on SBP (months) (<65 years, 12.0; 65 to <75, 11.4; 75 to <80, 11.3; ≥80, 10.0) compared with unadjusted analyses. Use of bevacizumab in subsequent postprogression regimens decreased with age. Incidence of targeted adverse events did not increase with age, except for arterial thromboembolic events (ATEs), for which Eastern Cooperative Oncology Group performance status, anticoagulation and arterial disease history were stronger prognostic factors than age. Conclusions: Elderly patients receiving bevacizumab with first-line chemotherapy showed treatment benefit, although there was reduced median survival with increasing age. There was no increased toxicity among elderly patients, except for risk of ATEs.