Impact of Preoperative Skeletal Muscle Mass and Quality on the Survival of Elderly Patients after Curative Resection of Colorectal Cancer.

Objective: Skeletal muscle loss (sarcopenia) is a prognostic factor in patients undergoing gastrointestinal surgery. However, the influence of muscle quality on prognosis remains unclear. We retrospectively examined preoperative skeletal muscle quantity and quality impact on survival of elderly patients undergoing curative resection of colorectal cancer. Methods: We examined data from 142 patients aged >= 75 years who underwent curative resection of colorectal cancer between 2007 and 2012. We determined the size and quality of skeletal muscles, represented by the psoas muscle mass index (PMI) and intramuscular adipose tissue content (IMAC), respectively, using a preoperative computed tomography image. Overall survival (OS) and relapse-free survival (RFS) rates were determined according to values of PMI, IMAC, and other prognostic factors. Results: OS and RFS rates in patients with low PMI were lower than those in patients with normal PMI. The OS and RFS rates in patients with high IMAC were also lower than those in patients with normal IMAC. PMI and IMAC were independent prognostic factors for OS (hazard ratio [HR], 3.81, and 3.04, respectively); IMAC was an independent factor for RFS (hazard ratio [HR], 3.03). Conclusion: Preoperative sarcopenia, indicating low quality and size of skeletal muscle, predicts mortality after curative resection of colorectal cancer in the elderly.