A case report of locally advanced triple negative breast cancer showing pathological complete response to weekly paclitaxel with bevacizumab treatment following disease progression during anthracycline-based neoadjuvant chemotherapy.

Introduction: Neoadjuvant chemotherapy (NAC) is the standard of care for locally advanced triple negative breast cancer, however, approximately 5% of cases show disease progression during NAC. Although downstaging is essential to create an opportunity for curative surgery and to improve the local control outcome in such a case, no additional line of chemotherapy has been established.

Case Presentation: A 60-year-old woman was referred to our hospital for an axillary mass presenting three weeks ago and was diagnosed as having right locally advanced (T2N2M0, stage IIIA) triple negative breast cancer. After two courses of epirubicine and cyclophosphamide as NAC, disease progression was recognized and curative resection was considered impossible due to enlarged axillary lymph nodes showing invasion to surrounding tissue. As second-line chemotherapy, weekly paclitaxel with bevacizumab treatment was initiated and significant shrinkage was immediately obtained. A clinically complete response was diagnosed after four courses of weekly paclitaxel with bevacizumab and she underwent a right breast mastectomy with axillary lymph node dissection without major complications. Histopathological examination of surgical specimens showed no residual invasive or noninvasive disease and she was diagnosed as having a pathological complete response.

Conclusions: Although the addition of bevacizumab to standard adjuvant chemotherapy is not recommended in unselected triple negative breast cancer, the potent effect on tumor shrinkage should be considered in the treatment of locally advanced triple negative breast cancer showing disease progression during standard NAC.