Sarcopenia does not limit overall survival after interstitial brachytherapy for breast cancer liver metastases

Purpose
Sarcopenia has been identified as a prognostic marker of clinical outcomes in several diseases. However, the influence of sarcopenia on non-surgical local treatments in breast cancer liver metastases (BCLM) is unknown. Therefore, the purpose of this study was to assess the effect of sarcopenia among patients with BCLM undergoing interstitial brachytherapy (iBT). Aim of the study was to evaluate the influence of baseline computed tomography (CT) psoas body composition parameters, including psoas muscle area (PMA), psoas muscle index (PMI), muscle density, and skeletal muscle gauge (SMG) on clinical variables in patients undergoing image-guided iBT.

Material and methods
Computed tomography scans of patients undergoing iBT for BCLM from 2006-2017 were retrospectively analyzed. PMA, PMI, and SMG were measured on pre-treatment CT scans. Parameters were associated with overall survival using logistic regression analysis.

Results
Sixty patients were included in the analysis. 27 patients (45%) were considered sarcopenic. Median overall survival was 27 months (SD = 4.0 months). In univariate analysis, neither PMA (HR = 0.956, 95% CI: 0.855-1.068, p = 0.423), average density (HR = 1.028, 95% CI: 0.985-1.072, p = 0.207), PMI (HR = 0.951, 95% CI: 0.701-1.290, p = 0.746), nor SMG (HR = 1.002, 95% CI: 0.998-1.006, p = 0.440) were associated with overall survival. There was no influence of sarcopenia on OS (HR = 0.975, 95% CI: 0.532-1.787, p = 0.934).

Conclusions
Sarcopenia does not predict overall survival in patients undergoing iBT for BCLM. Interstitial BT may therefore be a suggested treatment option in sarcopenic patients with BCLM eligible for local ablation.