Pathologic Complete Response in Triple Negative Breast Cancer Treated with Anthracycline Free Regimen: a case report

Abstract Triple-negative breast cancer (TNBC) is a highly aggressive malignancy with limited therapeutic options and elevated mortality rates. Chemo-immunotherapy according to the KEYNOTE-522 has established a new standard of care in the neoadjuvant setting, due to high rates of pathological complete response (pCR) and improved survival outcomes. Considering the efficacy scenario, it is essential to explore whether and when treatment de-escalation may be feasible to mitigate toxicity. We report the clinical case of a 54-year-old Caucasian woman with high-risk cT4a cN0 TNBC who achieved both clinical and pathological complete response despite early discontinuation of neoadjuvant therapy. Due to anthracycline extravasation, four cycles of anthracyclines, cyclophosphamide, and pembrolizumab were omitted. This case suggests a potential role for de-escalated regimens in selected patients. However, the absence of reliable predictive biomarkers limits appropriate patient selection. Further investigation is warranted to identify which patients could safely benefit from reduced-intensity approaches without compromising outcomes.