Why Genetic Testing Is Key for Ovarian Cancer Patients and Family Members

PARP inhibitors are drugs that work to prevent damaged cancer cells from repairing themselves and subsequently spreading. This makes PARP drugs a particularly good option for helping to ward off cancer recurrence.

Most recently, the American Society of Clinical Oncology (ASCO) released new guidelines recommending PARP inhibitors be offered to women, with or without genetic mutations, who are newly diagnosed with stage III or IV ovarian cancer and have improved with chemotherapy.

When a patient is diagnosed with ovarian cancer, Dr. Geller also sends their tumor out for testing as well.

There are two types of mutations doctors look for from genetic testing: germline (or hereditary) and somatic. Germline testing looks for genetic mutations that are present in the whole body. So whether it's a skin cell, a breast cell, or a colon cell that's being examined, they will all show the same mutation. These mutations can be passed down from parent to child, so the test results not only inform women of their own cancer risks but also those of family members.

The other type of genetic testing is called somatic testing. "Somatic mutations occur within the tumor itself, sometimes as a result of the type of cancer that you have," Dr. Geller says. Oncologists call these driver mutations that can help doctors and patients choose the best available treatment options. "Even if someone is BRCA-1 or -2 negative, or is germline-mutation negative, the good news is, there’s still hope that their tumor may have these somatic mutations.”

If so, they may be more likely to respond to a PARP inhibitor.

While initially, women with a BRCA-1 or BRCA-2 genetic mutation had been shown to respond especially well to PARP inhibitors after recurrence, and then in what’s called maintenance therapy, newer research has shown that women with the BRCA gene mutation (and indeed almost all women), can consider using PARP inhibitors throughout their treatment. The Food and Drug Administration has now approved niraparib (brand name ZEJULA) for almost all women regardless of whether they have the BRCA mutation, as part of an initial course of treatment, or what’s called front-line treatment.

However, Dr. Amanika Kumar of the Mayo Clinic who spoke to SurvivorNet, cautioned that women still need to speak with their doctor to evaluate the benefit of taking a PARP inhibitor to extend life, because there are very real side effects due to the toxicity of the drug. "Patients with HRD (homologous recombination deficiency) have a far better response than those without and those with BRCA mutations even more so. It is on us as clinicians to help patients understand the risks and benefits of treatment. Patients that have no mutation or HRD may choose not to go on maintenance (in fact I recommend they don't) because there is real toxicity to these meds."

Because every cancer is different, genetic testing allows doctors to tailor treatment specifically for each patient.

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