Impacts of Preoperative Psoas Muscle Mass and Visceral Fat Area on Postoperative Short- and Long-Term Outcomes in Patients with Gastric Cancer

Background Sarcopenia and obesity are associated with outcomes after surgery. However, few studies have investigated which more accurately predicts postoperative complications or prognosis in patients with gastric cancer. Methods A total of 567 consecutive patients with gastric cancer who underwent gastrectomy between 2010 and 2015 were retrospectively reviewed. Psoas muscle mass index (PMI) and visceral fat area (VFA) were measured by CT scan. Patients were divided into two groups based on PMI (PMI-H group: male >= 6.36 cm(2)/m(2), female >= 3.92 cm(2)/m(2); and PMI-L group: male < 6.36 cm(2)/m(2), female < 3.92 cm(2)/m(2)) and two groups based on VFA (VFA-H group: >= 100 cm(2); VFA-L group: < 100 cm(2)). The incidence of postoperative complications and the recurrence-free survival (RFS) were compared between the two groups. Results The incidence of postoperative complications was significantly higher in the VFA-H group than in the VFA-L group (35.1% vs. 20.3%; P < 0.001), whereas there was no significant difference between the PMI-H and PMI-L groups. Multivariate analysis showed that PMI-L and VFA-H were independent risk factors for pneumonia (odds ratio, 4.49; P = 0.018) and intra-abdominal abscess (odds ratio, 5.19; P = 0.004), respectively. While there was no significant difference in RFS between the VFA-H and VFA-L groups, the PMI-L group showed significantly worse RFS than the PMI-H group (P < 0.001). Conclusions PMI and VFA were useful predictive factors for postoperative pneumonia and intra-abdominal abscess, respectively. PMI might be a useful prognostic factor in patients with gastric cancer, but VFA is not.