Loss of muscle mass during preoperative chemotherapy as a prognosticator for poor survival in patients with colorectal liver metastases

Background: The survival impact of specific body composition changes during preoperative chemotherapy in patients with colorectal liver metastases undergoing curative-intent surgery remains unclear. This study aimed to determine the impact of changes in body weight and muscle mass during preoperative chemotherapy on survival after hepatectomy in patients with colorectal liver metastases. Methods: Consecutive patients with colorectal liver metastases undergoing preoperative chemotherapy and curative hepatectomy during 2009–2013 were retrospectively analyzed. Recurrence-free and overall survival were examined according to body compositions, including muscle mass, as measured by skeletal muscle index (area of muscle [cm ² ]/square of height [m ² ]), and body weight before and after preoperative chemotherapy. Results: The median follow-up duration in overall 169 patients was 47 months. Skeletal muscle index and body weight changed significantly during chemotherapy (skeletal muscle index: –0.52 cm ² /m ² , P =.03; body weight: +1.1 kg, P =.002). Patients with major muscle mass loss (≥7%) had significantly shorter median RFS than patients with no or minor muscle mass loss (<7%) (9.6 months vs 15.9 months; P =.02). Although major muscle mass loss was associated with poor outcome, skeletal muscle index before or after preoperative chemotherapy was not associated with recurrence-free or overall survival. On multivariate analysis, major muscle mass loss was independently associated with poorer recurrence-free survival (hazard ratio, 1.76; P =.045). Conclusion: Major loss of muscle mass but not body weight loss during preoperative chemotherapy is significantly associated with poor recurrence-free survival after hepatectomy in patients with colorectal liver metastases. The mechanisms mediating this association may inform future trials on maintaining muscle mass with dedicated nutrition and exercise programs to improve outcomes.