A New Option for Breast Cancer Prevention

Preventive drug for postmenopausal, high-risk women

A New Option for Breast Cancer Prevention

With special guest contributor Holly Pederson, MD

Advertising Policy

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

When we talk about drugs for breast cancer, we often focus on medications used for treatment after a diagnosis.

But medications can play a major role in prevention, as well. A recent study of the drug anastrozole (Arimidex) has brought that role to light yet again.

Below, my colleague Holly Pederson, MD, of Cleveland Clinic’s Breast Center, offers her perspective on the news about anastrozole and other preventive medications. There are more than 2 million post-menopausal women in this country who are healthy but who have an elevated risk of breast cancer. These women should know they have options.

A new option for prevention

In a prevention trial in the United Kingdom, researchers followed 3,864 postmenopausal women who were at high risk for breast cancer, either because of family health history or other factors. The researchers gave these women either anastrozole or a placebo daily for five years.

At the end of the trial, the results showed a 53 percent reduction in breast cancer risk in the group that received anastrozole compared with the placebo group. After five years, 2 percent of women on anastrozole had developed breast cancer, while 4 percent of those on a placebo had.

The bottom line: Postmenopausal women who are healthy but have a high risk of breast cancer now have four different preventive medications available.

Advertising Policy

Prevention is not new

Anastrozole is just the latest option to emerge for high-risk women.

Two other medications, tamoxifen and raloxifene, have been in use for years. Both drugs are selective estrogen receptor modulators (SERM). SERMs work by blocking the estrogen receptors in a woman’s breasts. Trials on both medications showed around a 50 percent reduction in the risk of ER-positive breast cancer, a type of cancer than depends on estrogen to spread.

More recently, another drug was added to the list: exemestane. Exemestane showed an even higher risk reduction at 65 percent. It’s called an aromatase inhibitor. Aromatase inhibitors work by blocking an enzyme that leads to estrogen production.

The latest drug studied, anastrozole, is also an aromatase inhibitor. Based on promising clinical trial results, we expect it to be added to clinical guidelines for the prevention of breast cancer, much like exemestane was.

The bottom line: Postmenopausal women who are healthy but have a high risk of breast cancer now have four different preventive medications available.

Starting the discussion

We believe all postmenopausal women who are at high risk of breast cancer should be aware of these promising preventive medications.

Advertising Policy

However, no drug is perfect, and side effects are a concern. For example, tamoxifen can increase the risk of uterine cancer or endometrial polyps. Both tamoxifen and raloxifene come with a slight risk of blood clots, as well.

Exemestane and anastrozole don’t come with the same blood clot risk, but they do both increase the risk of joint pain. And all four of these drugs can make hot flashes, night sweats and vaginal dryness worse — valid concerns for postmenopausal women.

That’s why we often recommend a trial run, and we pick the best option based on a woman’s individual case.  A 5-year course of these medications is recommended if they are well-tolerated; that is the typical length of time studied in clinical trials.

These medications won’t be right for everyone. But high-risk postmenopausal women deserve the opportunity to discuss them with their doctors, to weigh the pros and cons, and to come to an informed decision. At the least, they deserve to know that preventive options are available — and that those options are growing in number.

Advertising Policy
Stephen Grobmyer, MD

Stephen Grobmyer, MD

Stephen Grobmyer, MD, is Section Head of Surgical Oncology and the Director of Breast Services at Cleveland Clinic.
Advertising Policy