Impact of preoperative subcutaneous adipose, visceral adipose and skeletal muscle on the outcomes of the oldest-old colorectal cancer patients after surgery

Background: Colorectal cancer (CRC) is one of the most common tumors worldwide, with rising numbers of elderly patients affected. Nutritional status significantly influences tumor prognosis. We aimed to investigate the association of subcutaneous and visceral adipose tissue and skeletal muscle mass with the prognosis of the oldest-old patients with CRC, after surgery. Patients: We retrospectively reviewed 210 patients >75 years who underwent surgical treatment at the Department of Gastrointestinal Surgery, Beijing Hospital, between December 2010 and December 2020. Materials: Subcutaneous adipose, visceral adipose, and skeletal muscle areas were measured using BMI_CT. The cut-off values of the CT measurements were then confirmed using receiver operating characteristic (ROC) curve analysis. Results: Subcutaneous adipose tissue index (SATI), visceral adipose tissue index (VATI), and total adipose tissue index (TATI) were significantly associated with sex and BMI. Notably, the oldest-old CRC patients with high SATI, VATI, and TATI scores exhibited significantly higher rates of wound complications and reduced postoperative hospitalization durations. Intriguingly, patients with high VATI and TATI demonstrated significantly better 5-year Overall survival (OS), Cancer-specific survival (CSS), and Disease-free survival (DFS) than patients in the other groups. Similar results were observed in patients with a high visceral-to-subcutaneous fat ratio (VSR) and skeletal muscle index (SMI) scores. Conclusion: Significantly improving skeletal muscle content while concurrently managing the total adipose content, especially visceral adipose tissue, may aid in extending the survival time of oldest-old patients with CRC after surgery.