Invasive bilateral breast cancer and high grade serous ovarian cancer with BRCA1-germline mutation and brainstem metastasis under PARP inhibitors

For breast cancer patients, BRCA gene mutations are predictive of a good response to chemotherapy, but are hampered by a high risk of bilateral and synchronous or metachronous ovarian cancer. Novel therapies such as PARP-inhibitors have proven effective for BRCA1/2 mutated ovarian cancer. We present the case of a 50-year-old woman, initially diagnosed with bilateral luminal B breast cancer with BRCA1 mutation. She received neoadjuvant chemotherapy, modified radical mastectomy and bilateral adnexectomy, while subsequently identifying a synchronous advanced ovarian cancer, stage FIGO IIIC, followed by adjuvant platinum chemotherapy and external radiotherapy. After a 12 months disease-free interval a brainstem tumor was discovered, for which whole-brain radiotherapy was performed. She received 6 months of PARP-inhibitors through an early access program. With only a partial at the end of treatment, the brainstem tumor was still in progression. Due to evolution of the brain metastasis, second line chemotherapy (taxanes and Bevacizumab) was administered, with complete radiologic response. The particularity of this case resides in the coexistence of a breast and ovarian cancer in the same patient with BRCA1-germline mutation who responded to a new line of therapy – the PARP inhibitors. While being unable to perform a biopsy, we speculate that the brain metastasis in this case was most likely of breast origin.