Objective: Adipose tissue releases angiogenic factors that may promote tumour growth. We sought to determine whether body mass index (BMI), subcutaneous fat area (SFA), and visceral fat area (VFA) were associated with outcomes in patients given first-line bevacizumab-based treatment for metastatic colorectal cancer (MCC).
Patients: In 120 patients with MCC who received bevacizumab-based therapy (Bevacizumab Group, n=80) or chemotherapy alone (Chemotherapy Group, n=40) as first-line treatment, we used computed tomography to measure SFA and VFA. We evaluated associations linking BMI, SFA, and VFA to tumour response, time-to-progression (TTP), and overall survival (OS).
Results: Bevacizumab Group: median follow-up lasted 24 months [3-70]. BMI, SFA, and VFA values above the median (i.e. high BMI, high VFA and high SFA) were significantly associated with absence of a response. TTP was shorter in patients with high BMI (9 vs. 12 months; P=0.01) or high VFA (9 vs. 14 months; P=0.0008). High VFA was associated with shorter OS (P=0.0493). By multivariate analysis, high VFA was independently associated with response, TTP, and OS (P=0.008, P=0.005, and P=0.027, respectively).
Chemotherapy Group: median follow-up lasted 30 months [4-84]. BMI, SFA and VFA were not associated with response, TTP or OS.
In the whole population: interaction between VFA and bevacizumab administration was significant for response (P=0.005) and TTP (P=0.022), thereby confirming the results.
Conclusion: Our study provides the first evidence that high VFA independently predicts a poorer outcome in patients given first-line bevacizumab-based treatment for MCC. However, this predictive biomarker needs to be validated in a different data set.