BRCA2-mutant metastatic breast cancer: complete response with rucaparib maintenance

What happened, in summary

A 35-year-old woman was diagnosed with upfront metastatic breast cancer, meaning the disease had already spread when it was first found. The cancer was grade III invasive ductal carcinoma. HER2 amplification was not seen on FISH testing, and genetic testing found both germline and somatic BRCA2 mutations. Her disease involved right-breast nodules, axillary lymph nodes, and bone metastases, so the case is best described as Stage IV metastatic breast cancer rather than Stage III disease. Initial treatment used a taxane-platinum chemotherapy combination: paclitaxel 80 mg/m2 and carboplatin on days 1, 8, and 15 of each 28-day cycle for 6 cycles. This produced a near-complete response. She then moved to maintenance therapy with rucaparib 600 mg by mouth twice daily, letrozole 2.5 mg by mouth once daily, and zoledronic acid once every 3 months. Her blood counts were monitored monthly while she remained on this regimen. The case highlights the role of PARP inhibition in BRCA2-mutated metastatic breast cancer after a strong response to platinum-based chemotherapy. After 2 years on maintenance treatment, she was doing well and had maintained a complete response. Her course centers on systemic treatment for metastatic disease: a strong response to platinum-taxane chemotherapy, followed by ongoing PARP inhibitor maintenance, endocrine therapy, and bone-directed treatment. Her metastatic treatment sequence centered on platinum-taxane chemotherapy followed by PARP inhibitor maintenance, endocrine therapy, and bone-directed treatment; HER2-directed therapy, local breast surgery, and radiation were not part of the reported metastatic-treatment course. Because bone involvement was present, zoledronic acid every 3 months was part of maintenance care for skeletal disease control alongside the oral cancer-directed regimen.