Prognostic Value of Skeletal Muscle Depletion Measured on Computed Tomography for Overall Survival in Patients with Non-Metastatic Breast Cancer

Purpose: The purpose of this study was to evaluate the prognostic value of skeletal muscle depletion measured on computed tomography (CT) in patients with non-metastatic invasive breast cancer. Methods: This retrospective study included 577 consecutive women (mean age +/- standard deviation: 48.9 +/- 10.2 years with breast cancer who underwent a preoperative positron-emission tomography (PET)/CT scan and curative surgery between January 2012 and August 2014. The total abdominal muscle area (TAMA), subcutaneous fat area (SFA), and visceral fat area (VFA) were measured on CT images at the L3 vertebral level. Univariate and multivariate Cox proportional-hazard regression analyses were performed to evaluate whether there was an association between sarcopenia and overall survival (OS) outcome. Results: Of the 577 women, 49 (8.5%) died after a mean of 46 months. The best TAMA threshold for predicting OS was 83.7 cm(2). The multivariate Cox proportional-hazard analysis revealed that sarcopenia (TAMA <= 83.70 cm(2)) was a strong prognostic biomarker (hazard ratio [HR], 1.951; 95% confidence interval [CI], 1.061-3.586), along with large tumor size, axillary lymph node metastasis, high nuclear grade, estrogen receptor status, and adjuvant radiation therapy. In the subgroup analysis of patients aged >= 50 years, TAMA (<= 77.14 cm(2)) was a significant independent factor (HR, 2.856; 95% CI, 1.218-6.695). Conclusion: Skeletal muscle depletion measured on CT was associated with worse OS outcome in patients with non-metastatic breast cancer.