Impact of a Low Preoperative Body Mass Index on the Postoperative Complications and Overall Survival of Gastric Cancer Patients: a Systematic Review and Meta-analysis

Objective Obesity is related to various diseases and the risk of cancer. However, most studies overemphasize the risk of obesity, while ignoring the impact of underweight. In this study, we carried out a metaanalysis to assess the impact of a low preoperative body mass index on the postoperative complication and overall survival rates of gastric cancer patients. Methods We identified and selected relevant studies through Pub Med, Embase, the Cochrane Library databases, the web of science, China National Knowledge Infrastructure and Wanfang electronic databases up to February 2019. The relative risk and 95% confidence interval were used to assess the association between the BMI and outcomes of gastric cancer patients. Results Seventeen publications were included in the final meta-analysis. There was a significant increase in the risk of postoperative complications(RR: 1.30, 95% CI: 1.07-1.57, P < 0.05; I~2 =61.1%) in the patients with a low body mass index. Conclusion Further research, including larger-scale prospective studies, is needed to confirm this finding. For underweight patients with poor nutritional status, preoperative nutritional support and BMI adjustment may be helpful to improve the postoperative outcomes.