Skeletal Muscle Mass Depletion After Gastrectomy Negatively Affects the Prognosis of Patients With Gastric Cancer.

Background/Aim: Skeletal muscle mass (SMM) is often depleted in patients with gastric cancer undergoing gastrectomy. Using a novel method, we evaluated the effect of SMM depletion after gastrectomy on disease prognosis. Patients and Methods: The maximum cross-sectional area of the psoas-muscle (MCA-PM) was measured before surgery and at 1 year after in 233 patients with gastric cancer who underwent radical gastrectomy to determine the ratio (MCA-PMR) as an indicator of SMM depletion. Results: The MCA-PMR cutoff value was set at 90%, and patients were divided into the groups with <90% and >= 90%. MCA-PMR <90% was an independent prognostic factor for all patients. In 88 patients who received adjuvant chemotherapy including S-1, the 5-year cancer-specific survival rate was significantly better for those with MCA-PMR >= 90% than for those with MCA-PMR <90% (84.1% vs. 59.1%; p=0.010; hazard ratio=2.974; 95% confidence interval=1.241-7.124). Conclusion: SMM depletion after gastrectomy can be measured using the MCA-PMR. This novel measurement can be easily implemented in the clinical setting.