Can Aromatase Inhibitors Help With Ovarian Cancer?

Medically Reviewed by Melinda Ratini, MS, DO on July 22, 2022
3 min read

If you have ovarian cancer, your oncologist has probably recommended surgery and chemotherapy. While aromatase inhibitors usually don’t take the place of those treatments, they can offer extra help if you’re in a select group.

They’re a hormone therapy used to treat some ovarian tumors and low-grade ovarian cancers, but only in women who are past menopause.

Also, you’re more likely to benefit from these drugs if your cancer is estrogen receptor positive, meaning the hormone known as estrogen is fueling your cancer’s growth. Aromatase inhibitors work to lower your levels of estrogen.

These oral meds are usually taken once a day. They include the drugs letrozole (Femara), anastrozole (Arimidex), and exemestane (Aromasin).

They block aromatase, an enzyme your body uses to make estrogen from another hormone called androgen. This lowers your level of estrogen, which your cancer needs to grow.

In premenopausal women (who still get periods), the ovaries are largely responsible for making estrogen. But that changes after menopause. Then, your estrogen levels drop, and most of the estrogen your body produces is derived from androgen.

Aromatase inhibitors prevent that from happening. (Other drugs, such as tamoxifen, also block estrogen, but they work differently.)

Aromatase inhibitors provide systemic therapy, which means they work throughout your entire body (whereas surgery focuses on cancer cells in a very specific area of your body).

Some people consider them a targeted therapy, because they target the hormone estrogen. But when most cancer experts talk about “targeted therapies,” they’re usually referring to drugs like bevacizumab (Avastin). These aren’t hormonal therapies but instead focus on unique proteins of cancer cells.

Your oncologist, a doctor who specializes in cancer, will look at several things when deciding if aromatase inhibitors are right for you. These include whether:

  • You have a type of ovarian cancer that’s fueled by estrogen.
  • Your cancer has other specific molecular characteristics like biomarkers that are associated with good responses to aromatase inhibitors.
  • You have low-grade serous or endometrioid ovarian cancer. These rare subtypes of ovarian cancer have been shown to respond well to this treatment.
  • You have stage II-IV ovarian cancer, or you’re experiencing a cancer recurrence.
  • You’re past menopause.

Generally speaking, aromatase inhibitors help some ovarian cancer patients, and research in this area is ongoing. Experts are trying to learn more about how well this therapy works, who is most likely to benefit, and whether a subset of people with ovarian cancer might do better with it than with more standard treatments like chemotherapy.

It’s hard to measure exactly how effective these drugs are, partly because research on their use in ovarian cancer is limited.

But they can be used for different purposes in ovarian cancer.

For instance, they can be used in newly-diagnosed patients as an add-on treatment after they’ve had surgery, or after surgery and chemotherapy as “maintenance therapy.” That’s ongoing treatment to prevent your cancer from recurring or growing.

They can also be given to people having a recurrence of their cancer to help postpone additional chemotherapy and extend their life.

One study looked at women with low-grade serous carcinoma. Those who took aromatase inhibitors after surgery and chemo had a significantly longer period when their cancer didn’t progress than those who didn’t take them.

Another small study found that those with low-grade ovarian cancer or serous borderline ovarian tumors who took the aromatase inhibitor drug called anastrozole had some improvement in their pain, fatigue, and overall functioning for at least 6 months.

Aromatase inhibitors are more often used for those with low-grade serous ovarian cancer. But there’s some evidence they might help those with high-grade serous ovarian cancer, if they’ve had a recurrence. A recent study found they may enable some people with ovarian cancer to postpone further chemotherapy.

Aromatase inhibitors are usually well-tolerated. Only about 10% of those who take them have side effects. But for those who do, the most common ones are:

  • Joint pain/stiffness
  • Hot flashes
  • Fatigue/weakness
  • Insomnia
  • Nausea
  • Vaginal dryness
  • Sexual dysfunction
  • Increased blood pressure or cholesterol
  • Blood clots

There are also some rare (1 in 10,000 patients) adverse reactions, and they may include blisters, allergic reactions, liver inflammation, and bone loss.

Tell your oncologist immediately if you’re having any of these, whether they’re mild or severe.