Loss of lean body mass within one week as a major determinant for total weight loss at one month after gastrectomy for gastric cancer.
219 Background: Postoperative changes in body weight and composition during first 1 month after gastrectomy remained unclear. Methods: The patients who underwent gastrectomy for gastric cancer between May 2010 and October 2013 were examined. Body weight and composition were evaluated by bioelectrical impedance analyzer within 1 week before surgery (first measurement), at 1 week after surgery (second measurement), and at 1 month after surgery (third measurement). The changes of the early period were defined as the differences until the second measurement, while those of the late period as the differences from the second to the third measurement. Results: Two-hundred forty four patients were selected for this study. Total body weight loss (BWL) within 1 month was -3.4 kg and the rate of body weight at 1 month to the preoperative body weight was 94.1%. BWL was significantly greater in the early period rather than that of the late period (-2.1 kg vs -1.2 kg, p<0.001). In the early period, loss of lean body mass was significantly greater than loss of fat mass (-1.5 kg vs -0.6 kg, p<0.001). The same trend was observed regardless of type of gastrectomy and surgical approach. Conclusions: Loss of lean body mass within 1 week was a major determinant for total body weight loss at 1 month. To maintain lean body mass within 1 week and total body weight at 1 month, future trial should be focused on not the surgical approach but nutritional intervention within 1 week.