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Background and objective: Changes in body composition have been associated with both perioperative and long-term outcomes following oncological procedures across various cancer entities. However, the potential predictive role of bone mineral density (BMD) in patients with colorectal liver metastases regarding perioperative outcomes and long-term survival remains unclear. The aim of this study was to investigate the role of BMD as a prognostic factor in patients undergoing surgery for colorectal liver metastases, specifically in relation to perioperative morbidity and long-term survival.

Method: Consecutive patients who underwent curative-intent surgery for colorectal liver metastases at RWTH Aachen University Hospital between 2010 and 2021 were included in this retrospective analysis. BMD was measured using preoperative CT-based segmentation at the level of the 11th thoracic vertebra. Perioperative complications were stratified according to the Clavien–Dindo classification and the Comprehensive Complication Index (CCI). Explorative receiver-operating characteristic (ROC) analyses were conducted for complications and survival endpoints, defining cut-off values for osteopenia through area-under-the-curve (AUC) measurements and Youden Index assessment. Survival outcomes were compared using Kaplan-Meier curves and the log-rank test, while independent risk factors were identified using Cox-regression analysis.

Result: In the explorative analysis of 550 patients operated within the defined time period, BMD demonstrated good predictive ability for 3-year (AUC=0.755, p= 0.001), 5-year (AUC=0.753, p<0,001) and 10-year (AUC=0.749, p<0,001) mortality in male patients with synchronous liver metastases undergoing minor liver resection (n=74). Osteopenia in this subgroup was defined as BMD<130.135 HU and osteopenic patients (n=28, 37.84%) exhibited significantly higher 3-year (53.6% vs. 13%, p<0.001), 5-year (67.9% vs. 19.6%, p<0.001) and 10-year (71.4% vs. 21.7%, p<0.001) mortality compared with non-osteopenic patients. Osteopenia was an independent risk factor for reduced OS in the mentioned cohort (HR: 2.591; 95% CI: [1.018-6.598]; p=0.046). No significant differences in perioperative complications were observed.

Summary: This study demonstrates that osteopenia is an independent predictor of inferior survival in male patients with synchronous liver metastases undergoing minor liver resection. Further research is needed to validate these results.