Bevacizumab for metastatic colon cancer: does patient BMI influence survival?

Adipose tissue is considered to have endocrine properties, including factors that are considered to have angiogenic activity. The current study aimed to evaluate whether there was a difference in the efficacy of bevacizumab for metastatic colon cancer patients according to their BMI (kg/m). A retrospective review of the medical records of consecutive patients who were treated with bevacizumab from diagnosis for metastatic colon cancer between 2005 and 2011 was carried out. Data extracted from medical files included demographics, height, weight, comorbidities, treatment protocols, time to tumor progression (TTP), and time of death. Variables were further evaluated with respect to TTP and overall survival (OS). The final analysis included 184 patients. The median TTP was 11.7 months and the median survival was 27.6 months. Chemotherapy dose reduction [P>0.001, hazard ratio (HR)=0.6, 95% confidence interval (CI) 0.4-0.8] and male sex (P=0.03, HR=0.7, 95% CI 0.5-1.0) predicted shorter TTP. Multivariate analysis indicated that metastatic disease at initial presentation and/or diabetes were associated with worse OS: the median OS for diabetes was 20 versus 28.3 months for patients without diabetes (P=0.008, HR=2, 95% CI 1.2-3.4) and 23 months for patients with metastatic disease at initial presentation versus 31.4 months for recurrent disease (P=0.008, HR=1.6, 95% CI 1.1-2.2). No differences were found for different BMIs subdivided into groups with respect to OS (P=0.84) or TTP (P=0.75). Our study did not show that bevacizumab is less effective in patients with a high BMI. It did show that diabetes and/or metastatic disease at initial diagnosis are associated with a poorer outcome.