Visceral fat as a predictive marker of response to bevacizumab-based treatment in metastatic colorectal cancer.

Abstract

e14665 Background: A large amount of visceral adipose tissue might be correlated with high VEGF levels and with resistance to bevacizumab-based regimens in metastasic colorectal cancer (mCRC). The aim is to evaluate that abdominal obesity can be a predictive marker of response to bevacizumab-based therapy in mCRC. Methods: From January 2005 to December 2010, we performed a retrospective analysis of 74 consecutive patients with mCRC received bevacizumab-based first line treatment. Pretreatment CT was used to measure visceral fat volume (VFV), subcutaneous fat volume (SFV) an waist circumference (WC) in 74 patients with mCRC who received bevacizumab-based first-line treatment (bevacizumab group, n=37) or chemotherapy alone (chemotherapy group, n=37). Associations linkingVFV, SFV and WC to tumor response, progression free survival (PFS) and overall survival (OS) were evaluated. For all analyses, VFV, SFV and WC were dichotomized using the median as the cut-off point. Results: In the bevacizumab group, median follow-up lasted for 25 months (7-47). VFV, SFV and WC values were not associated with response or OS. PFS was shorter in patients with high VFV (12.8 vs 7.7 months; p=0.04). By multivariate analysis, high VFA was independently associated with PFS (HR=4.32, p=0.045). In the chemotherapy group, median follow-up lasted for 26 months (2-68). VFV, SFV and WC were not associated with response, PFS or OS. Conclusions: Visceral fat volume plays a role of predictive marker of PFS to bevacizumab-based therapy for Japanese patients with mCRC.