When Cancer Rxs Team Up

Aromatase inhibitors and bisphosphonates may improve breast cancer survival for postmenopausal women

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Sometimes it takes two. Two breast cancer medications, that is.

Two new studies from the UK found that aromatase inhibitors (AI) and bisphosphonates may improve the chances of survival for postmenopausal women with early breast cancer.

It was suggested that the two medications could be used together for additional benefits and fewer side effects.

Adam Brufksy, MD, PhD, an oncologist at the University of Pittsburgh Cancer Institute, told dailyRx News, "I really think this research is going to be practice-changing."

Most women do not develop breast cancer until after menopause. This is partly because the risk of cancer increases as people age.

Some breast cancers can be stimulated by the body’s own hormones, such as estrogen (the primary female sex hormone). Previous research has shown that some women who use estrogen to counteract menopausal symptoms are at higher risk of developing breast cancer.

AIs are medications that can counteract the estrogen stimulation effect.

Bisphosphonates are typically used to treat osteoporosis. These medications include alendronic acid (brand name Fosamax), ibandronic acid (Boniva) and risedronic acid (Actonel).

The first study, led by Mitch Dowsett, PhD, of The Royal Marsden Hospital and The Institute of Cancer Research in the UK, looked at more than 30,000 postmenopausal women with early breast cancer.

These women were given either an AI for five years or tamoxifen for the same amount of time. Tamoxifen (brand names Soltamox, Nolvadex) is currently a standard treatment for breast cancer.

The risk of death dropped by 15 percent in the women who took the AIs. The risk of cancer recurrence also dropped by 30 percent.

“Our global collaboration has revealed that the risk of postmenopausal women with the most common form of breast cancer dying of their disease is reduced by 40 percent by taking five years of an AI — a significantly greater protection than that offered by tamoxifen," said Dr. Dowsett, in a press release.

The second study, led by Robert Coleman, MD, a professor of oncology at the University of Sheffield in the UK, looked at 26 trials involving more than 18,000 women of all ages with early breast cancer.

The women who were given two to five years of bisphosphonate treatment saw a reduced risk of both cancer recurrence and death.

The risk of death dropped by 18 percent in the first 10 years after diagnosis, while recurrence dropped by 28 percent.

These results were only seen in postmenopausal women.

“These simple, well tolerated treatments should now be considered for routine use in the treatment of early breast cancer in women with either a natural or medically induced menopause to both extend survival and reduce the adverse effects of cancer treatments such as the aromatase inhibitors on bone health,” said Dr. Coleman, in a press release.

Lead statistician for both studies Richard Gray, PhD, from the University of Oxford, told dailyRx News that the two medications could be used together.

“The drugs are complementary, because the main side effect of aromatase inhibitors is an increase in bone loss and fractures, while bisphosphonates reduce bone loss and fractures as well as improving survival,” Dr. Gray said.

Although breast cancer treatment can be very expensive, both of these medications are available in generic form. Generic medications usually cost less than brand names.

Both studies were published in the July issue of the journal The Lancet.

Cancer Research UK and the UK Medical Research Council funded this research.

Study authors disclosed funding from some manufacturers of medications used in breast cancer and osteoporosis treatment, including Amgen, AstraZeneca, Bayer and Pfizer.

Review Date: 
July 23, 2015
Last Updated:
July 31, 2015