Bone Drug May Fight Breast Cancer

A drug used to combat bone loss may also fight breast cancer, a new study finds. The study included 1,803 women with early-stage breast cancer. All had surgery. They also took medicines to reduce estrogen in their bodies and keep the cancers from using estrogen to grow. Half of the women also received zoledronic acid. This drug is used to treat bone loss caused by cancer treatment or osteoporosis. Within four years, the cancer came back or spread in 54 women who received the extra drug and 83 who did not. That's a 36 percent lower risk with zoledronic acid. The study appeared in the New England Journal of Medicine.

What is the doctor's reaction?

Advances in the treatment of breast cancer have greatly improved the outlook for women with this common disease. For example, 35 years ago, about 3 out of 4 women with newly diagnosed breast cancer were alive 5 years later. Now, it's closer to 9 out of 10.

Here are some of the most important discoveries:

• Regular mammograms can lower the risk of death from breast cancer.

• Certain genes carried by women increase the risk of breast cancer.

• New combinations of drugs, radiation and hormonal treatments have improved survival.

• Proteins found on tumor cells can predict the response to certain drugs.

These advances did not come as single, dramatic "breakthroughs" or cures. Instead, improved survival has been gradual. Each discovery has added a bit to the more optimistic outlook we have today.

A new study describes another advance in the treatment of breast cancer. It's a small advance, but potentially important. Researchers from Vienna, Austria, looked at the use of hormonal treatment and zoledronic acid to treat breast cancer in younger women.

The women were ages 26 to 56 and had not been through menopause. They already had surgery for early-stage tumors. That is, the tumors were relatively small and had not spread far from the breast. All of the tumors were "endocrine responsive." This means that tumor cells had proteins (called receptors) that could link up with the hormones estrogen or progesterone. When these hormones grab on to tumor cell receptors, tumor growth can speed up.

Each woman received therapy with goserelin plus tamoxifen or anastrozole. These three medicines block the action of the sex hormones estrogen or progesterone, or they reduce the amount of these hormones. These "anti-hormones" help to stop tumors from growing and spreading.

Half of the women also received zoledronic acid. This medicine already is approved for the treatment of osteoporosis and some cancers that affect bones.

Women treated with zoledronic acid had a 36 percent lower risk of having their disease get worse than those who got hormonal treatment alone. Side effects related to zoledronic acid were minor. Bone and joint pain were slightly more common among women who received it.

Overall, treatment was highly effective. After 4 years, 90 percent of those receiving hormonal treatment alone and 94 percent of those who also got zoledronic acid were alive and cancer-free.

We've known for decades that blocking or reducing female hormones can help to slow the growth of breast tumors that have hormone receptors. But why should zoledronic acid help? It's not entirely clear. However, past research has suggested a few ways that zoledronic acid may fight tumors:

• Stopping creation of new blood vessels that provide nutrition to tumors

• Reducing the ability of tumors to invade nearby tissue

• Reducing tumors' ability to spread to bone

• Helping chemotherapy to work better against tumors

• Encouraging the body's immune system to fight tumors

This opens a new avenue for the treatment for breast cancer. The good news is that several similar drugs are already approved for other diseases. For example, zoledronic acid is found in Reclast. This is an osteoporosis treatment that is given directly into a vein once a year. Other drugs in the same family are alendronate (Fosamax), risedronate (Actonel) and ibandronate (Boniva). So, we already know a great deal about the risks, side effects and safety of medicines like zoledronic acid.

What changes can I make now?

You can reduce your risk of breast cancer and help to make sure that if you have the disease it is caught early.

• Have mammograms regularly if you are age 40 or older. Women at high risk should consider getting mammograms before age 40, having genetic testing, and having an MRI. You can find out more about your risk at this National Cancer Institute Web site.

• Maintain a healthy body weight.

• Exercise regularly.

• Don't take hormone replacement treatment (or take the lowest dose for the shortest possible time).

• Avoid excess drinking of alcohol.

• Don't smoke.

• Breastfeed your children.

• Choose a low-fat diet with plenty of vegetables.

If you have breast cancer, talk to your doctors about the option of receiving zoledronic acid along with other treatments.

What can I expect looking to the future?

This new study is a good example of how a medicine for one condition can turn out to be effective in another. You can expect to hear about more research on new uses for approved medicines. You can also expect researchers to explore which women with breast cancer are most likely to respond to zoledronic acid. This study enrolled younger women with early-stage breast cancer. But zoledronic acid could be effective for older women and for those who have more advanced disease.

Finally, new therapies that use information about the genes of women with breast cancer and their tumors are on the horizon. As a result, you can expect the outlook for women with breast cancer to keep getting better.