Primary tumor location is a risk factor for postoperative development of sarcopenia related to poor outcomes in patients with colorectal cancer

Abstract

Abstract Background The present study aimed to investigate the loss of skeletal muscle mass after surgery and how it affects long-term outcomes. Methods This retrospective analysis included clinical stage I- IV colorectal cancer patients who underwent curative resection between April 2012 and March 2014 at the University of Tokyo Hospital. We excluded patients with recurrence within 12 months of colorectal resection. The psoas muscle area at the third lumbar vertebra level was evaluated by computed tomography and was divided by the square of height to obtain the psoas muscle mass index (PMI). Sarcopenia was defined using the generally accepted PMI cut-off values for Asian adults of 6.36 cm2/m2 for males and 3.92 cm2/m2 for females. Results Among 511 enrolled patients, 359 were analyzed and 169 had preoperative sarcopenia. One year after colorectal resection, 24 patients (12.6%) had newly diagnosed sarcopenia, while 46 (27.2%) had recovered from sarcopenia. Rectal cancer was identified as an independent risk factor for the postoperative development of sarcopenia (OR 5.05; 95%CI 0.08–0.48; p = 0.0003). The median follow-up period was 7.0 years, and 5-year OS and DFS rates were 94.3 and 80.4%, respectively. Postoperative sarcopenia was an independent risk factor for shorter DFS in a multivariate analysis (HR 1.62; 95%CI 1.06–2.49; p = 0.0267). Conclusion Postoperative sarcopenia one year after surgery was associated with poor DFS, and, thus, the prevention of skeletal muscle loss needs to be considered during postoperative surveillance, particularly in rectal cancer patients without sarcopenia before surgery.