Eighteen months after completing surgical debulking and chemotherapy for stage III high-grade serous ovarian cancer, 56-year-old Lily experienced a rising CA-125 level. At her oncologist’s recommendation, Lily started an aromatase inhibitor, but it did not stop the rising tumor marker.
After she began experiencing symptoms of bloating and mild abdominal pain, Lily and her oncologist decided to proceed with second-line chemotherapy. As she left the office, Lily remarked that she did not complete genetic testing when she was originally diagnosed because she does not have any children or a family history of ovarian cancer and she was concerned that her insurance would not cover the testing.
What Would You Do?
Despite recent changes in the National Comprehensive Cancer Network Genetic/Familial High-Risk Assessment: Breast and Ovarian Cancers guidelines, myths continue to prevail around criteria for BRCA 1 and 2 testing and when such testing should take place (see sidebar).
In Lily’s case, genetic testing to identify BRCA 1 or 2 mutation status at the time of her initial diagnosis could have given prognostic information and predicted her response to platinum-based chemotherapy. BRCA 1 and 2 mutated cancers are more chemosensitive overall and respond well to platinum-based chemotherapy.
In the second-line setting, BRCA status predicts patient response to a poly ADP-ribose polymerase inhibitor (PARPi), which prevents PARP proteins from repairing single-strand breaks in cancer cells’ DNA. Cell death because of PARPi in the presence of a BRCA 1 or 2 mutation is called synthetic lethality. In other words, the synergistic effect of PARP inhibition in a BRCA 1 or 2 mutated cell leads to cell death.
Oncology nurses can help women with ovarian cancer understand that in addition to familial risk assessment, BRCA 1 and 2 testing can guide treatment recommendations and provide prognostic information.