The effect of body mass index at cancer diagnosis on survival of patients with squamous cell head and neck carcinoma

Abstract The aim of this study is to investigate the prognostic role of body mass index (BMI) and survival from head and neck cancer (HNC). We performed a pooled analysis of studies included in the International Head and Neck Cancer Epidemiology consortium in order to investigate the prognostic role of BMI and survival from HNC. We used Cox proportional hazards models to estimate the adjusted hazard ratios (HR) for overall survival and HNC-specific survival, by cancer site. The study included 10,177 patients from 10 studies worldwide. Underweight patients had lower overall survival (HR = 1.69, 95%CI: 1.31–2.19) respect to those having normal weight with consistent results across the HNC sites. Overweight and obese patients with oropharyngeal cancers had a favourable HNC-specific survival (HR = 0.50 (95%CI: 0.33–0.75) and HR = 0.51 (95%CI: 0.36–0.72), respectively). Among ever smokers overweight and obese patients showed a favourable HNC-specific survival (HR = 0.69 (95%CI: 0.56–0.86) and HR = 0.70 (95%CI: 0.61–0.80)). Our findings show that high BMI values at cancer diagnosis predict the survival rates in smoking patients with HNC. This association may be explained by residual confounding, reverse causation, and collider stratification bias, but may also suggest that a nutritional reserve may help patients survive HNC cancer.