Intermuscular fat density as a novel prognostic factor in breast cancer patients treated with adjuvant chemotherapy

Background: Body composition, including sarcopenia and fat parameters, has received much attention as a prognostic factor in breast cancer. Methods: A total of 479 breast cancer patients who underwent surgery and received adjuvant chemotherapy were enrolled in this study. Body composition, including the index and density of skeletal muscle, visceral fat, subcutaneous fat, and intermuscular fat calculated by CT scan, was used as a prognostic factor. The endpoints were breast cancer-specific survival (BCSS) and overall survival (OS). Results: The number of patients with stages I, II, and III was 146 (30.5%), 237 (49.5%), and 96 (20%), respectively. Sarcopenia and muscle density were not significant prognostic factors for BCSS and OS. A high visceral fat index (VFI) was an independent prognostic factor for BCSS (HR, 2.55; 95% CI 1.10–5.95, p = 0.03) and OS (HR 2.55, 95% CI 1.26–5.16, p = 0.01). In addition, high intermuscular fat density (IMFD) was also a significant prognostic factor for BCSS (HR, 2.95; 95% CI 1.34–6.46, p = 0.007) and OS (HR 2.28, 95% CI 1.22–4.26, p = 0.01) in multivariate analysis. Conclusion: VFI and IMFD were significant prognostic factors for BCSS and OS in breast cancer patients treated with adjuvant chemotherapy.