[Effect of Post-Gastrectomy Adjuvant S-1 Chemotherapy on Muscle Volume in Gastric Cancer Patients].

Objective: To examine the effect of S-1 adjuvant chemotherapy on muscle volume after curative gastrectomy in gastric cancer patients.

Patients: Forty-eight gastric cancer patients (31 men and 17 women) who underwent curative gastrectomy (distal gastrectomy: n=37, and total gastrectomy: n=11) between April 2010 and July 2011 were enrolled in this study. Sixteen patients underwent S-1 adjuvant chemotherapy (S-1 group) for 1 year after the operation, and 32 patients did not (NT group).

Methods: The psoas muscle areas were measured at the fourth lumbar vertebrae on CT images obtained before the operation, and at 6, 12, and 24 months after the operation. Muscle areas was statistically examined by comparing the preoperative and postoperative ratios.

Results: The muscle areas 12 months after the operation decreased to 0.86 ± 0.11 in the S-1 group and to 0.96 ± 0.08 in the NT group (p<0.05), and the significant difference disappeared at 24 months (0.93 ± 0.10 vs. 0.93 ± 0.11, NS). In the patients who underwent distal gastrectomy, the muscle areas decreased to 0.90 ± 0.05 in the S-1 group and to 0.96 ± 0.09 in the NT group at 12 months (p<0.05). Meanwhile, in those who underwent total gastrectomy, the muscle areas decreased to 0.80 ± 0.15 and 0.93 ± 0.03, respectively (NS).

Conclusions: S-1 adjuvant chemotherapy affected muscle volume loss after gastrectomy in the gastric cancer patients, but the patients recovered from the adverse effect by 12 months after chemotherapy.