Nutritional and Clinical Factors Affecting Weight and Fat-Free Mass Loss after Gastrectomy in Patients with Gastric Cancer.

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 ( < 0.001). At one to three months postoperative, females who had undergone chemotherapy tended to significantly lose weight ( = 0.016). Females with a history of chemotherapy also showed a reduction in fat-free mass for one to three months ( = 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.