Impact of being underweight on the long-term outcomes of patients with gastric cancer

The aim of this study was to investigate the impact of being underweight on the long-term outcomes of gastric cancer patients. This study reviewed the medical records of 638 patients with gastric cancer who underwent gastrectomy between January 2003 and December 2011. The patients were divided into three groups according to the WHO classification: underweight (BMI < 18.5 kg/m(2)), normal weight (BMI a parts per thousand yen18.5 and < 25 kg/m(2)), and overweight (BMI a parts per thousand yen25 kg/m(2)). A multivariate analysis was performed to identify prognostic factors. The mean BMI immediately before surgery was 22.5 kg/m(2) (standard deviation, 3.3 kg/m(2)). According to the BMI subgroup, 73 patients (11.4 %) were underweight, 431 patients (67.6 %) were of normal weight, and 134 patients (21 %) were overweight. The 5-year overall survival (OS) rate was 66.6 % in the underweight patients, 81.3 % in the normal weight patients, and 79.9 % in the overweight patients (P = 0.001). The OS rate was significantly lower in the underweight patients than in the normal weight and overweight patients among those with stage I disease, and it was also lower than in the normal weight patients among those with stage II and III disease. In the multivariate analysis, being underweight was found to be an independent predictor of OS, but it was not an independent predictor among patients with stage II and III disease. Being underweight is a simple and reliable predictor of a worse long-term outcome among gastric cancer patients. Being underweight is considered to be associated with a higher risk of non-cancer death.