LAUSR

BACKGROUND Preoperative sarcopenia in older patients is a risk factor for adverse outcomes after colorectal cancer (CRC) surgery. Longitudinal changes in muscle mass in this group have not been studied previously although muscle wasting may have prognostic significance regarding survival. We aimed to determine the association between muscle wasting and overall survival (OS) in older patients who underwent surgery for CRC. METHODS Patients ≥70 years who underwent surgery for non-metastatic CRC in Gelre hospitals, The Netherlands, between 2011 and 2015 were included. Cross-sectional area of skeletal muscle was measured at the level of the 3rd lumbar vertebra on preoperative and postoperative abdominal CT-scans. Patients who had >1 standard deviation decrease in muscle mass were considered to have muscle wasting. Cox regression analysis was used to evaluate associations between muscle wasting and OS. RESULTS 233 patients were included (40% female, median age 76 years). Thirty-four patients had muscle wasting. After a median follow-up of 4.7 years, 53 (23%) patients died. The 3-year mortality rate was higher in patients with muscle wasting (27% vs 14%, p = .05). In multivariable analysis adjusted for age, recurrent disease and preoperative muscle mass, muscle wasting was associated with reduced OS (HR 2.8, 95% CI 1.5-5.4, p = .002). CONCLUSION Muscle wasting predicted poorer survival in older patients who underwent CRC surgery. Measuring changes in muscle mass may improve risk prediction in this patient group. Future studies should address the etiology of muscle wasting in older patients with CRC. Whether perioperative exercise interventions can prevent muscle wasting also warrants further study.