Postoperative changes in body composition after laparoscopic and open resection of colorectal liver metastases: data from the randomized OSLO-COMET trial.

Background: Low muscle mass is negatively associated with survival in patients undergoing surgery for colorectal cancer. Current evidence is limited regarding whether the surgical approach for liver resection of colorectal metastasis impacts postoperative changes in body composition and whether preoperative body composition can impact complication rate and survival.

Method: This study included patients previously included in the randomized OSLO-COMET trail where patients was allocated to laparoscopic or open liver resection for colorectal liver metastasis. CT scans 0-3 months before and 2-6 months after liver resection were segmented with the artificial intelligence-based tool BodySegAI to measure skeletal muscle mass (SM), visceral adipose tissue (VAT), and inter- and intramuscular adipose tissue (IMAT). SM, VAT and IMAT was compared between the open and laparoscopic group and as predictors for 5-year survival and postoperative complications.

Results: This study included 216 patients, median age was 67, 127 (59%) were male, 91 (42%) had primary tumor in rectum and 86 (40%) had multiple liver metastasis. There was no significant difference in postoperative change in SM, VAT or IMAT between those undergoing laparoscopy or open surgery. In multivariate analysis, high preoperative IMAT was a predictor for increased risk of postoperative complications (HR (95% CI): 1.045 (CI 95%: 1.003-1.089), p = 0.034). Moreover, postoperative increase in IMAT was a negative predictor for 5-year survival (HR (95%CI):1.009 (1.003-1.016), p = 0.003).

Conclusion: Postoperative change in body composition did not differ between patients randomly assigned to open or laparoscopic liver resection for colorectal metastasis. High preoperative IMAT was associated with an increased risk of postoperative complications.