Pathologic Complete Response Rates in Young Women with BRCA1-positive Breast Cancers After Neoadjuvant Chemotherapy

Purpose: To estimate the rate of pathologic complete response (pCR) to neoadjuvant chemotherapy in BRCA1 mutation carriers according to chemotherapy regimen.

Patients And Methods: From a registry of 6,903 patients, we identified 102 women who carried a BRCA1 founder mutation and who had been treated for breast cancer with neoadjuvant chemotherapy. Pathologic complete response was evaluated using standard criteria.

Results: Twenty-four (24%) of the 102 BRCA1 mutation carriers experienced a pCR. The response rate varied widely with treatment: a pCR was observed in one (7%) of 14 women treated with cyclophosphamide, methotrexate, and fluorouracil (CMF); in two (8%) of 25 women treated with doxorubicin and docetaxel (AT); in 11 (22%) of 51 women treated with doxorubicin and cyclophosphamide (AC) or fluorouracil, doxorubicin, and cyclophosphamide (FAC), and in 10 (83%) of 12 women treated with cisplatin.

Conclusion: A low rate of pCR was observed in women with breast cancer and a BRCA1 mutation who were treated with AT or CMF. A high rate of pCR was seen after treatment with cisplatin. An intermediate rate of PCR was associated with AC or FAC. The relative benefits of AC and platinum therapy need to be confirmed through follow-up of this and other cohorts.