The Impact of Body Mass Index on the Surgical Outcomes of Patients With Gastric Cancer

This study aimed to investigate the impact of body mass index (BMI) on the short-term and long-term results of a large cohort of gastric cancer (GC) patients undergoing gastrectomy.Recently, the "obesity paradox" has been proposed, referring to the paradoxically "better" outcomes of overweight and obese patients compared with nonoverweight patients. The associations between BMI and surgical outcomes among patients with GC remain controversial.A single-institution cohort of 1249 GC patients undergoing gastrectomy between 2000 and 2010 were categorized to low-BMI (<18.49 kg/m), normal-BMI (18.50-24.99 kg/m), and high-BMI (≥25.00 kg/m) groups. The postoperative complications were classified according to the Clavien-Dindo system, and their severity was assessed by using the Comprehensive Complication Index (CCI). The impact of BMI on the postoperative complications and overall survival was analyzed.There were 908, 158, and 182 patients in the normal-BMI, low-BMI, and high-BMI groups, respectively. The overall morbidity in the high-BMI group (24.7%) was higher than that in either the low-BMI or the normal-BMI group (20.9% and 15.5%, respectively; P = 0.006), but the mean CCI in the low-BMI group was significantly higher (8.32 ± 19.97) than the mean CCI in the normal-BMI and high-BMI groups (3.76 ± 11.98 and 5.58 ± 13.07, respectively; P < 0.001). The Kaplan-Meier curve and the log-rank test demonstrated that the low-BMI group exhibited the worst survival outcomes compared with the normal-BMI group, whereas the high-BMI group exhibited the best survival outcomes (P < 0.001). In multivariate analysis, BMI was identified as an independent prognostic factor. In the stage-specific subgroup analysis, a low BMI was associated with poorer survival in the cases of stage III-IV diseases.Low BMI was associated with more severe postoperative complications and poorer prognosis. Despite a higher risk of mild postoperative complications, the high-BMI patients exhibited paradoxically "superior" survival outcomes compared with the normal-BMI patients. These findings confirm the "obesity paradox" in GC patients undergoing gastrectomy.