The Body Mass Index Paradox in Head and Neck Cancer: A Systematic Review and Meta-Analysis.

The body mass index (BMI) paradox describes that among patients with certain cancers, higher pretreatment BMI may be associated with improved survival. We examine the impact of BMI on overall survival (OS) in head and neck squamous cell carcinoma (HNSCC) patients. A literature search was performed, and articles using hazard ratios to describe the prognostic impact of BMI on OS in HNSCC were included. Random-effects DerSimonian and Laird methods were employed for meta-analysis. Meta-analysis of OS indicated a lower hazards of death in the overweight (BMI: 25 kg/m2-30 kg/m2) compared to the normal weight (BMI: 18.5 kg/m2-25 kg/m2). This protective relationship loses significance when BMI exceeds 30 kg/m. Underweight patients (BMI < 18.5 kg/m2) demonstrate higher hazards of death compared to normal weight patients. Compared to HNSCC patients with normal weight, being overweight up to a BMI of 30 kg/m is a positive predictor of OS, while being underweight confers a prognostic disadvantage. Further studies are needed to determine the mechanisms by which increased body mass influences survival outcomes in HNSCC.