Lean body mass wasting and toxicity in early breast cancer patients receiving anthracyclines

Background: Sarcopenia refers to the reduction of both volume and number of skeletal muscle fibers. Lean body mass loss is associated with survival, quality of life and tolerance to treatment in cancer patients. The aim of our study is to analyse the association between toxicities and sarcopenia in early breast cancer patients receiving adjuvant treatment. Materials and Methods: Breast cancer patients who have received anthracyclinebased adjuvant treatment were retrospectively enrolled. CT scan images performed before, during and after adjuvant chemotherapy were used to evaluate lean body mass at third lumbar vertebra level with the software Slice Omatic V 5.0. Results: 21 stage I-III breast cancer patients were enrolled. According to the skeletal muscle index at third lumbar vertebra cut-off =38.5 cm2/m2, 8 patients (38.1%) were classified as sarcopenic before starting treatment, while 10 patients (47.6%) were sarcopenic at the end of treatment. A lower baseline L3 skeletal muscle index is associated with G3-4 vs G0-2 toxicities (33.4 cm2/m2(31.1-39.9) vs 40.5 cm2/m2(33.4-52.0), p = 0.028). Similarly skeletal muscle cross sectional area was significantly lower in patients with G3-4 toxicities (86.7 cm2(82.6-104.7) vs 109.0 cm2(83.3-143.9), p = 0.017). L3 skeletal muscle index is an independent predictor of severe toxicity (p = 0.0282) in multivariate analysis. Conclusion: Lean body mass loss is associated with higher grade of toxicity in early breast cancer patients receiving adjuvant chemotherapy.