Low body mass index is an independent predictor of poor long-term prognosis among patients with resectable gastric cancer

BACKGROUND: The association between body mass index (BMI) and clinical outcomes remains unclear among patients with resectable gastric cancer. AIM: To investigate the relationship between BMI and long-term survival of gastric cancer patients. METHODS: This retrospective study included 2526 patients who underwent radical gastrectomy for gastric cancer between September 2013 and June 2018. The patients were divided into four groups: Group A (low BMI, < 18.5 kg/m(2)), group B (normal BMI, 18.5-24.9 kg/m(2)), group C (overweight, 25-29.9 kg/m(2)), and group D (obese, ≥ 30 kg/m(2)). Clinicopathological findings and survival outcomes were recorded and analyzed. RESULTS: Preoperative weight loss was more common in the low-BMI group, while diabetes was more common in the obese group. Upper-third gastric cancer accounted for a large proportion of cases in the higher BMI groups. Major perioperative complications tended to increase with BMI. The 5-year overall survival rates were 66.4% for group A, 75.0% for group B, 77.1% for group C, and 78.6% for group D. The 5-year overall survival rate was significantly lower in group A than in group C (P = 0.008) or group D (P = 0.031). Relative to a normal BMI value, a BMI of < 18.5 kg/m(2) was associated with poor survival (hazard ratio: 1.558, 95% confidence interval: 1.125-2.158, P = 0.008). CONCLUSION: Low BMI, but not high BMI, independently predicted poor survival in patients with resectable gastric cancer.