When chemotherapy wins: pathologic complete response in early triple negative breast cancer

Abstract

Triple-negative breast cancer (TNBC) is an aggressive subtype characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and HER2 expression, accounting for 10–20% of all breast cancers, yet showing notable sensitivity to cytotoxic chemotherapy, a phenomenon termed the “triple-negative paradox.” Neoadjuvant chemotherapy (NAC) is the standard of care for stage II–III TNBC, with pathologic complete response (pCR) rates of 30–40% that correlate with favorable survival. We report a 62-year-old woman with invasive ductal carcinoma grade 1, ER-negative, PR-negative, HER2-negative, and Ki-67 index 30–40%, diagnosed as TNBC, with imaging showing a cT2cN0cM0 lesion. She underwent NAC with doxorubicin and cyclophosphamide for 4 cycles followed by weekly paclitaxel for 12 cycles, resulting in significant tumor regression. Surgery confirmed no residual invasive carcinoma (Payne–Miller 5), consistent with pCR. mmune checkpoint inhibitor therapy was not administered, due to underlying scleroderma, . Post-neoadjuvant PET-CT demonstrated no residual disease. This case illustrates that anthracycline- and taxane-based NAC alone can achieve pCR in early TNBC, highlighting the prognostic significance of pCR in predicting favorable outcomes and underscoring the importance of multidisciplinary, individualized management to optimize patient care.