Body Mass Index and Bevacizumab-Based Therapy in Advanced Colorectal Cancer Patients: Evaluation of Clinical Outcome

Aim: Although high body mass index (BMI) has been associated with advanced colorectal cancer (ACC) prognosis, this effect is not consistent across different studies. As bevacizumab is the backbone therapy of ACC and obesity is associated with increased serum levels of vascular endothelial growth factor (VEGF), the aim of this study was to evaluate the impact of BMI on prognosis in ACC patients enrolled onto a phase III randomized clinical (NCT01878422). Methods: The relationship between baseline BMI and progression-free (PFS) and overall survival (OS) was assessed in 376 patients randomized to receive FOLFOX4 or FOLFIRI with or without bevacizumab. BMI was defined as follows: normal Results: Information on BMI at baseline was available in 368 ACC patients. Of these, 198 (53.8%) showed normal weight, 133 (36.1%) were overweight and 37 (10.1%) were obese. At a median follow up of 36 months (range 1-65), median PFS was 8.9 months (95% CI 8.0-9.6), 8.9 months (95% CI 7.4-9.9) and 7.8 months (95% CI 4.7-9.7) in normal, overweight and obese patients, respectively (p 0.251). Median OS was 21.3 months (95% CI 18.4-23.6), 21.0 months (95% CI 17.5-25.4) and 21.7 months (95% CI 14.0-28.8), respectively (p 0.461). Of the 368 patients, 175 received first-line chemotherapy with bevacizumab and 193 underwent chemotherapy alone. No statistically significant differences in terms of mPFS or mOS were observed in the two arms with regard of BMI (see table). Conclusions: Chemotherapy + bevacizumab Chemotherapy BMI Category No. of patients No. of events Median PFS (95% CI) No. of patients No. of events Median PFS (95% CI) p 87 83 9.7 (8.1-11.3) 111 106 8.3 (7.0-9.0) 0.409 25-29.9 66 58 9.8 (7.4-13.1) 67 59 8.6 (6.3-9.5) 0.436 ≥30 22 21 7.8 (4.6-11.3) 15 14 6.5 (2.3-9.7) 0.843 p 0.261 0.681 BMI Category No. of patients No. of Events Median OS (95% CI) No. of patients No. of Events Median OS (95% CI) p 87 62 21.8 (16.3-27.4) 111 86 20.8 (18.4-23.5) 0.844 25-29.9 66 49 19.3 (12.7-24.8) 67 46 24.3 (18.2-29.1) 0.287 ≥30 22 20 20.5 (10.4-25.2) 15 11 24.9 (11.5-29.6) 0.265 p 0.230 0.612 BMI at baseline was not associated with the prognosis of ACC patients. Although adipose tissue may release angiogenic factors, obesity does not seem to be a predictive factor for response to a first-line bevacizumab- based therapy in ACC patients. Disclosure: All authors have declared no conflicts of interest.