Association of postoperative delayed bowel function recovery with weight and muscle loss at 6 months in colorectal cancer patients.

Background: Delayed bowel function recovery (DBFR) is a common postoperative complication after colorectal cancer (CRC) resection. This study aimed to investigate the association between postoperative DBFR and 6-month weight and muscle mass loss in patients with CRC, to inform optimized postoperative prognostic management. Methods: A total of 618 patients with CRC were prospectively enrolled. Body weight and five anthropometric parameters (including mid-upper arm circumference) were measured within 3 days before surgery. Skeletal muscle cross-sectional area at the L3 vertebral level was quantified using preoperative abdominal CT scans, with the skeletal muscle index (SMI) subsequently calculated. DBFR was defined as the absence of first flatus and defecation within 72 postoperative hours. All participants completed a 6-month follow-up, and body weight, SMI and the five anthropometric measurements were reassessed at the follow-up endpoint. Multivariate linear regression models were applied for statistical analyses. Results: Postoperative DBFR was nominally or significantly correlated with lower final body weight, reduced SMI, decreased mid-upper arm circumference, calf circumference and hip circumference, as well as reduced triceps skinfold thickness at 6-month follow-up. Notably, DBFR was significantly associated with larger declines from baseline to follow-up in body weight, SMI, mid-upper arm circumference, calf circumference, waist circumference, hip circumference and triceps skinfold thickness. Conclusion: Postoperative DBFR correlates with medium-term weight and skeletal muscle loss in patients undergoing CRC surgery. Upon further external validation, DBFR may act as a predictive risk factor for these unfavorable nutritional outcomes.