Overweight is associated with better prognosis in metastatic colorectal cancer patients treated with bevacizumab plus FOLFOX chemotherapy

Introduction
Previous studies showed that high and low body mass index (BMI) was associated with worse prognosis in metastatic CRC (mCRC). Whether BMI is a prognostic or predictive factor in mCRC is unclear. We aimed to assess efficacy outcomes according to BMI in patient with metastatic colorectal cancer treated with bevacizumab plus FOLFOX chemotherapy regimen in second-line treatment.

Material and methods
The analysis of 237 patients with metastatic colorectal cancer treated with bevacizumab plus FOLFOX in the second line (treated from January 2014 to August 2018) in 4 reference oncological centers in Poland.

Results
The median age of the patients was 65 years (range 34–82). The median overall survival (OS) and progression-free survival (PFS) of the all 237 patient was 14.6 and 8.8 months, respectively. Comparison of obese patient (BMI > 30 kg/m2) vs. overweight patients (BMI ≥ 25 to < 30 kg/m2) vs. normal BMI range patients revealed a significant improvement of median OS (17.5 vs. 14.3 vs. 13.1 months, p = 0.01) and median PFS (9.4 vs. 9.1 vs. 7.3 months, p = 0.03). The Cox hazard model showed that the BMI class is an important risk factor. However, the Cox model also showed that the significance of the BMI class applies only to patients with BMI < 25 kg/m2. This rule applies to both OS and PFS. The regression analysis also confirmed that there is a statistically significant relationship between the length of OS and PFS and the BMI value. Higher BMI was associated with a better prognosis. There were no differences in responses to treatment bevacizumab and FOLFOX chemotherapy and number adverse events according to BMI values.

Conclusions
Patients with mCRC treated with chemotherapy with bevacizumab in second-line treatment with higher BMI compared with normal weight patients have better prognosis in terms of PFS and OS. In this group, we found no evidence of changes in safety profile depending on BMI. Nevertheless, further large randomized studies are needed to assess the body weight on the effectiveness of chemotherapy in combination with bevacizumab.