Computed tomography-measured bone mineral density as a surrogate marker of survival after resection of colorectal liver metastases

BACKGROUND: Osteopenia/osteoporosis, characterized by low bone mineral density (BMD), is a potential prognostic factor in cancer patients. We conducted a retrospective single-institution study to evaluate the prognostic impact of preoperative low BMD on colorectal liver metastases (CRLM) in patients undergoing liver resection. METHODS: BMD was assessed in 281 patients undergoing initial liver resection for CRLM by analyzing the preoperative computed tomography (CT) images at the level of the eleventh thoracic vertebra as the region of interest. Survival outcomes were compared between the two groups divided by the median BMD value and prognostic factors after surgery were assessed. Propensity score-based inverse probability weighting (IPW) was applied to adjust for between-group differences in baseline characteristics. RESULTS: The low BMD group had significantly more older patients (≥75 years) (P=0.01) and a higher incidence of bilobar metastases (P=0.005) than the normal BMD group. After IPW adjustment, overall survival (OS) was significantly poorer (P=0.02) and recurrence-free survival was slightly poorer (P=0.05) in the low BMD group than in the normal BMD group. IPW-adjusted regression analysis revealed that low BMD was independently associated with an adverse OS (hazard ratio, 1.42; 95% CI, 1.04–1.93; P=0.03), in addition to other factors such as tumor number, extrahepatic disease, preoperative carcinoembryonic antigen level (≥5 ng/mL), and right-sided primary tumor location. CONCLUSIONS: Preoperative CT-measured low BMD can serve as a surrogate marker of adverse OS in CRLM patients undergoing liver resection. Prevention and early intervention for osteopenia/osteoporosis may be suggested for these patients.