Can sarcopenia predict complete response after total neoadjuvant therapy in advanced rectal cancer? A multicentre observational cohort study.

BACKGROUND: The association between sarcopenia and response to neoadjuvant treatment remains unclear. This study investigates sarcopenia as a predictor of overall complete response (oCR) after Total Neoadjuvant Therapy (TNT) for advanced rectal cancer.

METHOD: A prospective observational study was performed of patients with rectal cancer undergoing TNT at three South Australian hospitals between 2019 and 2022. Sarcopenia was diagnosed by pretreatment computed tomography measurement of psoas muscle cross-sectional area at the third lumbar vertebra level, normalised for patient height. The primary endpoint was oCR rate defined as the proportion of patients who achieved either clinical complete response (cCR) or pathological complete response.

RESULTS: This study included 118 rectal cancer patients with an average age of 59.5 years, 83 (70.3%) of whom formed the non-sarcopenic group (NSG) and 35 (29.7%) the sarcopenic group (SG). The oCR rate was significantly higher in NSG compared with the SG (p < 0.001). cCR rate was significantly greater in NSG compared with the SG (p = 0.001). Multivariate analysis revealed sarcopenia (p = 0.029) and hypoalbuminemia (p = 0.040) were risk factors for cCR and sarcopenia was an independent risk factor for oCR (p = 0.020).

CONCLUSION: Sarcopenia and hypoalbuminemia were negatively associated with tumour response following TNT in advanced rectal cancer patients.