Supplementary Material for: Do we need the anthracyclines for elderly patients with triple negative breast cancer?

Objectives Triple-negative breast cancer (TNBC) requires chemotherapy-based systemic treatment which is usually anthracycline-based (AB). The cardiotoxicity of AB regimens is especially relevant in the elderly population. Therefore, we retrospectively compared survival and toxicity between elderly patients with early TNBC receiving anthracycline-based or anthracycline-free (AF) adjuvant chemotherapy to evaluate whether elderly patients with TNBC could be spared anthracycline-related toxicity without compromising survival. Methods The study population comprised 221 women with TNBC older than 65 years from the SUCCESS A and SUCCESS C studies, who underwent primary surgery and received either AB (3x fluorouracil-epirubicin-cyclophosphamide followed by 3x docetaxel) or AF (6x docetaxel-cyclophosphamide) adjuvant chemotherapy according to a standardized protocol. The two groups were compared regarding clinicopathological parameters (pT, pN, grading, histological subtype, type of surgery, adjuvant radiotherapy) and side effects using chi-square tests, and regarding survival (overall survival, invasive disease-free survival, breast-cancer specific survival, distant disease-free survival) using log-rank tests and cox regressions. Results There was no significant difference between the two groups regarding any of the clinicopathological parameters and no significant difference was observed in survival parameters. However, elderly patients with the AB regime had significantly more often grade 3 or 4 adverse events (75.2% vs 50.6%, p < 0.001) during adjuvant chemotherapy than patients with the AF regimen. Conclusion In our retrospective analysis of SUCCESS A and C trial, the use of AF chemotherapy in elderly patients with TNBC was associated with similar survival rates but less toxicity compared to AB chemotherapy. Further randomized controlled trials with AF regimen focussing on elderly patients with TNBC are necessary to confirm our results.