Background and Objective The relationship between survival in gastric cancer patients and the status of microsatellite instability (MSI) has not yet been established. The purpose of this meta‐analysis was to obtain integrated and more precise data for the value of MSI as a prognostic marker in gastric cancer. Methods A comprehensive systematic review and meta‐analysis were conducted using major electronic databases (PubMed, EMBASE, and the Cochrane Central) with keywords related to “microsatellite instability,” “gastric cancer,” and “prognosis.” Results Twenty‐four studies with 5,438 participants (712 cases were MSI gastric cancer) were included for pooling risk estimates of MSI in gastric cancer. Seventeen studies reported overall survival. The pooled hazard ratio (HR) for overall survival of MSI vs. non‐MSI was 0.72 (95%CI: 0.59–0.88, P = .001) in a random‐effects model. In the sensitivity analysis, the result from the most recent study showed the most heterogeneity. Conclusion MSI gastric cancer was associated with good prognosis but there was heterogeneity in the recent studies. Changed epidemiology and effects of chemotherapy are potential causes of heterogeneity. Establishing a consensus for defining MSI in gastric cancer should be preferred for future studies. J. Surg. Oncol. 2014; 110:129–135.

After a gastrectomy, the nutritional status of patients with gastric cancer has great effect on the treatment outcome and patients’ quality of life. We investigated the changes in body composition and nutrient intake after gastrectomy in 288 gastric cancer patients. A multiple linear regression analysis was used for each time period to verify the effects of nutritional and clinical factors on weight and fat-free mass loss rates. Gastric cancer patients who underwent a gastrectomy continued to experience weight and fat-free mass loss until three months after surgery and became stagnant at six months. The marginal mean of calorie intake per weight was 24.5, 26.8, and 29.4 kcal at one, three, and six months. The protein intake per kg lean mass was 1.14, 1.14, and 1.16 g at one, three, and six months, respectively. One month after surgery, the rate of weight loss increased significantly in females who received chemotherapy (p < 0.001). At one to three months postoperative, females who had undergone chemotherapy tended to significantly lose weight (p = 0.016). Females with a history of chemotherapy also showed a reduction in fat-free mass for one to three months (p = 0.036). Calorie intake was a significant factor in preventing fat-free mass weight loss at one month after surgery. Chemotherapy was an independent factor affecting the weight and fat-free mass loss rate up to six months after gastrectomy. Careful monitoring of weight and muscle mass changes following active nutritional intervention for sufficient nutrition support could be helpful for patients after gastrectomy.