An observational cohort study of bevacizumab and chemotherapy in metastatic colorectal cancer patients: safety and efficacy with analysis by age group

Abstract

Bevacizumab improves survival when added to chemotherapy in metastatic colorectal cancer (mCRC). We assessed the safety and efficacy of bevacizumab in mCRC patients ≥70years old (YO) vs. those <70 YO. mCRC patients treated from 2005-2012 who received chemotherapy (physician's choice) plus bevacizumab were included. The primary end point was safety; secondary objectives were progression-free survival (PFS) and overall survival (OS). Data was collected retrospectively. Three-hundred eight patients (92 ≥70 YO, 216 <70 YO) with 20.5month median follow-up were included. Of the patients, 1.9% died due to bevacizumab-related adverse effects; all were <70 YO. Grades 3-5 adverse events of interest for bevacizumab in patients ≥70 YO included hypertension (37.0%), venous thromboembolism (6.5%), wound-healing complications (5.4%), bleeding (7.6%), fistula (4.3%), arterial thromboembolism (3.3%), congestive heart failure (2.2%), and proteinuria (grades 1-2 only, 14.1%). Treatment was stopped due to adverse effects in 6.0% of older patients. Older patients had significantly more ischemic heart disease and hypertension at baseline, and were treated less with FOLFOX and more with 5FU/LV monotherapy; nevertheless, OS and PFS were similar in younger and older patients. Compared to younger patients, in older patients, rates of proteinuria (all grades 1-2) were significantly higher (14.1 vs. 5.6%, p=0.012) and rates of treatment-related hypertension (grades 3-5) were marginally higher (37 vs. 25.9%, p=0.053); rates of other adverse events were similar in the two groups. In our patient population, bevacizumab was safe and effective in older as well as younger patients.