Prognostic Value of Body Mass Index in Stage II/III Colon Cancer: Posthoc Analysis From the TOSCA Trial

-BMI plays a key role in colon cancer, despite its prognostic impact is not fully elucidated. -Our study aimed to evaluate the prognostic impact of BMI in stage II/III colon cancer patients included in the TOSCA trial. -BMI > 30 kg/m2 was an independent prognostic factor for RFS and OS in stage III colon cancer patiens.Background: High body mass index (BMI) plays a key role in the development of colon cancer (CC). Our post-hoc analysis from the TOSCA trial analyzed the association between BMI and survival outcomes in terms of relapse-free survival (RFS) and overall survival (OS) in stage II/III CC patients.Patients and methods: Patients enrolled in the TOSCA trial between 2007-2013 with BMI data entered the study. The prognostic impact of BMI on survival outcomes was investigated through uni-and multivariable Cox regression analyses.Results: Overall, 1455 patients with stage II/III CC patients were included. The median follow-up was of 61.5 months; 16.1% of patients relapsed, 11.2% died and 19.5% patients relapsed or died. No impact of BMI on RFS was detected at univariate or multivariable analyses. By univariate analysis for OS, a significantly impact of a BMI > 30 kg/m2 was reported (HR [ > 30 vs < 25] 1.57, 95% CI 1.00-2.47, p = 0.049; HR [ > 30 vs < 30] 1.55, 95% CI 1.01-2.37, p = 0.045). Multivariable analyses did not confirm this data. In the subgroup of stage III patients, a negative survival impact of BMI was found in univariate and multivariable models both for RFS and for OS.Conclusions: In our study, obesity with BMI > 30 kg/m2 was an independent prognostic factor for RFS and OS in CC patients treated with adjuvant chemotherapy, regardless of its duration (3 or 6 months). However, the prognostic impact of adiposity and body composition measurement should be considered to better classify patients with high visceral fat and refine their risk assessment.

Automated summary

In this study, obesity with a BMI > 30 kg/m2 was identified as an independent prognostic factor for relapse-free survival (RFS) and overall survival (OS) in colon cancer patients.