Low-grade serous ovarian cancer with BRAFV600E mutation treated with metronomic chemotherapy — a case report and literature review

Introduction. Ovarian cancer (OC) is the leading cause of cancer death worldwide. In Poland, it is the fourth leading cause of death from neoplasms in women. OC is a heterogeneous disease with low-grade cases characterized by a better prognosis, but poor chemosensitivity. Metronomic chemotherapy (MC) may be a beneficial approach. Case presentation. We present a patient with low-grade serous ovarian cancer (LGSOC) with long-term disease control achieved with MC despite being resistant to standard-dose chemotherapy with paclitaxel and carboplatin. Overall survival (OS) of the patient was 65 months. MC was administered most of the time. The patient was treated with two metronomic regimens: topotecan plus cyclophosphamide and vinorelbine plus methotrexate, both in combination with hormone therapy. The cancer was found to harbor the BRAF V600E mutation (v-raf murine sarcoma viral oncogene homolog B1, a valine-to-glutamic acid substitution at position 600), but that did not impact the treatment. Conclusions. LGSOC has distinct features from high-grade serous ovarian cancer (HGSOC). MC may be a valuable option in LGSOC despite being understudied. The BRAF V600E mutation occurs in 2–33% of low-grade serous ovarian tumors. It is a more common finding in LGSOC than in HGSOC. BRAF inhibition in OC may be a new therapeutic option. Some BRAF inhibitors have already been registered for solid tumors with this mutation.