Making the Move to Maintenance Therapy for Ovarian Cancer

In the early days of your cancer when you were first diagnosed, your doctor likely did a series of tests to learn as much as possible about your cancer's genes. One question was whether youor your cancercarry the BRCA gene mutations. These are inherited changes to the BRCA1 and BRCA2 genes, which normally help cells repair their damaged DNA.

The other question was whether you have a genetic factor known as homologous recombination deficiency (HRD), which also affects cells' abilities to repair themselves. Both of these genetic changes create vulnerabilities in your cancer cells that your treatment team will use to your advantage.

"What it means is you’re more susceptible to chemotherapy and you have what’s called a 'targetable mutation,' Dr. Ulm says.

Targeting Mutations With Treatment

If you do have BRCA mutations and/or HRD, your doctor can put you on a relatively new group of maintenance therapies called PARP inhibitors. These drugs capitalize on your cells' reduced DNA repair ability to prevent cancer cells from fixing themselves.

The American Society of Clinical Oncology (ASCO)  guidelines recommend 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.

Three PARP inhibitors are currently approved for ovarian cancer maintenance:

• Olaparib (Lynparza)
• Niraparib (Zejula)
• Rucaparib (Rubraca)

Your doctor will probably give you the drug they're most comfortable using, and the one they think you'll tolerate the best, Dr. Ulm says.

The big advantage to these drugs is that they might help you live longer. Research shows that taking a PARP inhibitor daily for two years "decreases the risk of the cancer coming back and increases survival," he adds.

PARP Inhibitor Side Effects: What to Expect

Any medication you take to manage your cancer has pros and cons. The pros are that the drug keeps your cancer at bay. The cons are its potential side effects. Because PARP inhibitors are a type of chemotherapy, they can damage healthy cells along with cancer cells.

Which side effects you end up having can vary, based on the drug you take. "Some cause a little more nausea, or affect bone marrow a little more," Dr. Ulm says. Fatigue is one of the most common side effects, affecting more than half of people who take these drugs.

These are some other side effects people who take PARP inhibitor drugs may experience:

• Indigestion
• Diarrhea
• Constipation
• Belly pain
• Low numbers of red blood cells that carry oxygen to your body, called anemia
• Low numbers of platelets that help your blood to clot, called thrombocytopenia

Side effects are usually worst at the beginning of treatment, but they should gradually improve the longer you're on the medication. "I generally tell my patients the first month on maintenance therapy can be a little rocky," Dr. Ulm says. "You’re still trying to adjust the dose and figure out the right dose for the patient."

After the first month or two, you should level out and start to feel more comfortable on the medicine, he says. But if you do have any problems from your PARP inhibitor, reach out to your doctor for guidance. Chances are, your medical team can adjust the dose or prescribe medicines to manage your side effects.

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