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

Corresponding author: Nong Xu, MD, Department of Medical Oncology, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Shangcheng District, Hangzhou, Zhejiang 310000, China, Tel: 0571 8723 5896; Email: nongxu@zju.edu.cn. Introduction Gastric cancer is one of the most common malignant tumors in the world and the third leading cause of morbidity and mortality [1]. It has been reported that preoperative malnutrition or a poor nutritional status are present in about 80% of patients with advanced gastric cancer [2]. Most underweight patients experience symptoms such as depression, apositia, hyperthyroidism, intestinal malabsorption and age-related muscle loss. Tumor growth can induce systemic inflammation and comorbid diseases, which may lead to excessive nutritional consumption [3]. It is well known that obesity is related to various diseases, including the risk of cancer. However, the risks associated with obesity are overemphasized, while ignoring the impact of underweight. Many studies have found an adverse influence of a low body mass index (BMI) on patients with gastric cancer [4,5]. Some researchers found that a low BMI in patients with gastric cancer was associated with a high risk of postoperative complications and overall survival (OS) [4,6-8]. However, others found no association [9-13]. In view of the contradictory conclusions, we performed a meta-analysis and tried to provide a more precise estimate of the association between a low preoperative BMI and the development of postoperative complications, as well as the long-term survival of gastric cancer patients.