Prognostic Impact of a Nutritional Index Including Muscle Volume in Stage 4 Colorectal Cancer

BACKGROUND: Nutritional status influences cancer prognosis. Measurement of the area of the psoas muscle on computed tomography is useful for evaluation of skeletal muscle mass and prediction of prognosis. PATIENTS AND METHODS: The psoas muscle index (PMI) was determined in 42 patients undergoing surgery for stage 4 colorectal cancer. Patients were classified into high and low PMI groups using a cutoff of 5.5×10-4 cm2 m-2 Relationships of PMI with prognosis, chemotherapy period, and postoperative complications were examined. RESULTS: The 3-year overall survival rate was 24.0%. PMI was significantly associated with 3-year OS in univariate (high vs. low PMI: 43.0% vs. 12.9%, p=0.0415) and multivariate (p=0.0146) analyses. A low PMI was associated with a shorter period of chemotherapy. A reduction in PMI was a predictor of a poor prognosis. CONCLUSION: PMI status is related to the period of chemotherapy and is an independent prognostic factor in patients with stage 4 colorectal cancer.