Gender differences in the correlation between prognosis and postoperative weight loss in patients with non-small cell lung cancer.

OBJECTIVES: The aim of this study was to investigate gender differences in the relationship between preoperative body mass index (BMI), postoperative body weight change and prognosis in patients with non-small cell lung cancer (NSCLC).

METHODS: Two hundred and sixty-three patients with NSCLC were enrolled in this study. Preoperative BMI was categorized based on WHO definition as follows: underweight (BMI <18.5): 21 patients (8.0%), normal (18.5 ≦ BMI <25): 179 patients (68%), overweight and obese (BMI ≧25): 63 patients (24%). Several factors such as age, sex, cancer stage, body weight change and BMI were recorded and correlated to the postoperative overall survival (OS).

RESULTS: For male patients, those in the low-BMI group had the worst prognosis (P < 0.05) whereas female patients with low BMI did not. Male patients with low BMI had statistically significant poorer prognosis compared to corresponding female patients (P < 0.05). Male patients with more than 5% body weight loss within 1 year after operation when compared to preoperative body weight had poorer prognosis than those with less than 5% body weight loss (P < 0.001). Furthermore, these male patients had statistically significant worse prognosis than the corresponding female patients (P < 0.05). In multivariable analysis, gender, more than 5% of body weight loss compared to preoperative body weight, and pathological stage were independent prognostic factors in NSCLC.

CONCLUSIONS: This study illustrates significant gender differences in the relationship between prognosis and BMI or body weight change in patients with postoperative NSCLC.