Impact of body mass index on survival of esophageal squamous carcinoma patients in southern China

Background: Although high body mass index (BMI) increases risk for developing esophageal adenocarcinoma (EAC), the prognostic influence of BMI is unknown in esophageal squamous carcinoma. Methods: BMI was calculated using measured height and weight at the first diagnosis and categorized as overweight (25 to 29.9 kg/m(2)), normal (18.5 to 24.9 kg/m(2)) or underweight (<18.5 kg/m(2)). Survival was compared by using the log-rank test on the Kaplan-Meier life table. Multivariate Cox regression analysis was used to evaluate whether BMI was an independent prognostic factor for disease-specific survival (DSS). Results: Among 1,176 esophageal squamous carcinoma patients, 146 (12.4%) were categorized as overweight, and 277 (23.6%) underweight. More patients in the underweight group had anemia (P=0.001), weight loss (P=0.035) and R1 resection (P<0.001). Less patients in the underweight group received adjuvant chemotherapy (P=0.01). Patients in the overweight group had a higher incidence rate of high blood pressure (P<0.001), diabetes (P<0.001) and coronary artery diseases (P<0.001). Moreover, more patients in the overweight group had a lower TNM stage (P=0.003). In the univariated analysis, high BMI was significantly associated with better DSS (P=0.013). Conclusions: After adjusting for covariates enrolled for study, high BMI was an independent prognostic factor in weight loss esophageal squamous carcinoma patients.