Sarcopenia kinetics and colorectal cancer outcomes: Post-operative development of sarcopenia is a poor prognostic indicator of survival following colorectal cancer surgery.

Abstract

Sarcopenia is defined by a paucity of skeletal muscle mass, strength and function. The relationship between pre-operative sarcopenia and poor surgical outcomes in colorectal cancer (CRC) is well described. This study investigates the novel concept of 'sarcopenia kinetics'-the change in sarcopenia status over time. Specifically, it aims to assess the association between sarcopenia kinetics and surgical outcomes in patients who have undergone CRC resection. An observational cohort study of consecutive patients who underwent surgery between 2016 and 2020 at a tertiary referral centre in Sydney, Australia, was performed. Pre-operative and post-operative CT scans were reviewed to calculate pre-operative and post-operative skeletal muscle indices (SMI). Sarcopenia was defined by the lowest quartile of sex-specific pre-operative SMI. Survival analysis was performed on the basis of change in SMI and sarcopenia classification, with primary end points of overall survival (OS) and disease-free survival (DFS). Overall, 545 patients underwent surgery for CRC during the study period. Of these patients, 186 met inclusion criteria, having accessible pre-operative and post-operative CT scans. The study population was 36% female, with a mean age of 76.0 years (SD 11.7). Over a 4.4-year median follow-up, 55 (28%) developed recurrence, and 85 (43%) died, with a 1-year OS of 87.1% (95% CI 81.4-91.2), 5-year OS of 58.6% (95% CI 50.8-65.6) and 5-year DFS of 50.4% (95% CI 42.8-57.5). Post-operative decrease in SMI was associated with poorer OS (HR 1.81 [95% CI 1.16-2.82], p = 0.008). Patients who became sarcopenic post-operatively demonstrated the poorest OS (HR 2.36 [95% CI 1.22-4.58], p = 0.011) and DFS (HR 2.61 [95% CI 1.42-4.80], p = 0.002) when compared with patients who were never sarcopenic. Sarcopenia kinetics, on the basis of SMI change and change in sarcopenia status, are associated with OS and DFS in patients undergoing CRC surgery. Decreasing SMI is associated with poorer OS, while patients who become sarcopenic post-operatively have the poorest outcomes. Sarcopenia kinetics have utility as a prognostic indicator and may represent a modifiable risk factor warranting further investigation.