Body mass index at diagnosis and prognostic significance on head and neck carcinoma survival

Abstract

Background :Haed and Neck Cancer (HNC) is the 6th most frequent cancer in men and the 13th in women worldwide. Several factors are known to be associated with an increase of mortality, such as advanced tumour stage, HPV infection, diet, smoking status and alcohol consumption. Growing amount of evidence on other type of cancers suggest higher BMI as being positively associated with survival. Nevertheless little is known about HNC. We aim to investigate relationship between BMI and survival in HNC. Methods A pooled analysis of cohort studies participating to the INHANCE Consortium was conducted. Descriptive analysis has been conducted to describe the population included in the analysis. Survival was considered as overall survival (OS) and disease specific survival (DSS). The impact of BMI on HNC-survival was calculated using the Cox's proportional hazards model both in the univariate and in multivariate analysis. Results A total of 5,835 patients recruited by five study centres met the inclusion criteria: Canada participated with 2161 cases (37%), Brasil with 2,482 (42.5%), United States with 599 (10.3%), Japan with 291 (4,99%) and Argentina with 90 (1.54%). The mean age was 59 years old (SD 11). 81.3% (n = 4673) were men, 60.9% (n = 3260) of patients were diagnosed a tumor in stage I or II. Regarding risk factors, 50.5% (n = 2,648) were overweight (36.6%, n = 1,839) or obese (13.9%,n = 809) with 6.8%(n = 340) being underweight. 75.2% (n = 3,764) were current (48.4%, n = 2,423) or former drinkers (26.8%, n = 1341), and 81.8% (n = 4,685) were current (44.6%, n = 2552) or former (37.2%, n = 2,133) smokers. HPV status was positive in 662 of patients. When considering OS, the Cox-regression analyses showed that normal BMI, overweightness and obesity were associated to an increased OS compared to underweight status, irrespective of the site of tumor (normal: HR 0.61, 95% CI 0.51-0.73; overweight: HR 0.50, 95% CI 0.41-0.60; obese: HR 0.50, 95% CI 0.39-0.62). Also when considering DSS, normal BMI, overweightness and obesity were positively associated to DSS in HNC overall (respectively HR 0.59, 95% CI 0.47-0.73; HR 0.51, 95% CI 0.40-0.65; HR 0.51, 95% CI 0.38-0.68) and in oropharynx localization (respectively HR 0.55, 95% CI 0.36-0.84; HR 0.35, 95% CI 0.21-0.57; HR 0.40, 95% CI 0.22-0.72). Conclusions Our study leads us to conclude that being obese or overweight increases survival probably because being underweight increases the risk of complications in patients who can not feed well (due to dysphagia) with a progressive organic deterioration and already debilitated.