Breast Cancer Medication Guidelines Updated

< Jul. 14, 2010 > -- Guidelines for using certain medications for treating the most common form of breast tumor have been updated by a leading group of cancer experts.

After a systematic review of medical research on the subject, experts report that adding an aromatase inhibitor, which is a medication that reduces the amount of estrogen produced in the body, has clearly been shown to reduce the number of tumor recurrences in postmenopausal women compared with the standard medication tamoxifen, which works by blocking the action of estrogen on cancer tumors that are estrogen-receptor positive (ER positive).

The American Society of Clinical Oncologists (ASCO) published the new guidelines this week in the Journal of Clinical Oncology. The paper essentially brings guidelines into alignment with current practice.

The new guidelines replace previous guidelines issued in 2002, and subsequent updates in 2003 and 2004.

The committee preparing the guidelines recommends that all postmenopausal women with ER positive breast cancer use aromatase inhibitors either before or after tamoxifen.

They also conclude that women could use them as long as five years after tamoxifen therapy to lower their risk that the cancer will reoccur.

New Guidelines Reinforce Current Practice

"This is actually reinforcing clinical practice," says Dr. Crystal Denlinger, assistant professor of medical oncology at Fox Chase Cancer Center in Philadelphia. "In general, for postmenopausal women, we are offering them aromatase inhibitors based on the single studies that have been referenced [in these guidelines] and what has already been reported in national meetings."

Those studies and presentations, Dr. Denlinger adds, "have uniformly demonstrated the superiority of aromatase inhibitors over tamoxifen or a switching strategy or an extended strategy."

Tamoxifen has been a mainstay of treatment for decades, while aromatase inhibitors are a more recent entry into the field. Both medications are used as "adjuvant" therapy, meaning they are used after surgery and chemotherapy and/or radiation to prevent the cancer from coming back.

Aromatase Inhibitor Effective Alone or In Combo

The committee reviewed recent studies which had investigated aromatase inhibitors and/or tamoxifen in women with this particular subtype of breast cancer.

Using an aromatase inhibitor alone or with tamoxifen therapy improved disease-free survival compared with using tamoxifen alone. It also reduced the risk of the cancer spreading to other parts of the body. The spread of cancer into other parts of the body is called metastasis.

Aromatase inhibitors are not effective in women who are pre- or peri-menopausal when they are diagnosed, according to the experts. These women should be given tamoxifen for five years.

All three aromatase inhibitors on the market - Arimidex (anastrozole), Femara (letrozole) and Aromasin (exemestane) - were essentially equal in their benefit.

Consider Side Effects

Side effects that may be caused by these medications need to be taken into account when prescribing.

"We've learned a huge amount about the various side effect profiles of these products," says Dr. Harold J. Burstein, co-chair of the ASCO committee which prepared the guidelines and associate professor of medicine at Harvard Medical School and Dana-Farber Cancer Institute in Boston. "Aromatase inhibitors are clearly associated with osteoporosis and with bone and joint [conditions]. They might also be associated with a greater risk of hypertension and high cholesterol."

For its part, tamoxifen is also associated with serious side effects, which can include cataracts and uterine cancer as well as life-threatening blood clots and stroke.

And cost will also be a factor in decision-making.

"Aromatase inhibitors are very expensive. And sometimes we have to make decisions about using drugs that are probably a little less effective but at the same time we have to take into account the financial standpoint," says Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge. "Are [aromatase inhibitors] better than tamoxifen? Yes, in two areas: preventing recurrent disease in other parts of the body and in preventing a second, separate breast cancer. But the [financial] costs are much more expensive."

According to the new guidelines, 20 milligrams of tamoxifen costs $21.90 a month, while Arimidex can cost $379.80. However, the aromatase inhibitor anastrozole recently became available as a generic, which should lower the cost significantly, according to Dr. Burstein.

Always consult your physician for more information.

More About Hormone Therapy for Breast Cancer

Hormones are chemicals produced by glands, such as the ovaries and testicles. Hormones help some types of cancer cells to grow, such as breast cancer and prostate cancer. In other cases, hormones can kill cancer cells, make cancer cells grow more slowly, or stop them from growing. Hormone therapy as a cancer treatment may involve taking medications that interfere with the activity of the hormone or stop the production of the hormones. Hormone therapy may involve surgically removing a gland that is producing the hormones.

If you have breast cancer, your physician may recommend a hormone receptor test of the tumor to help determine treatment options and to help learn more about the tumor. This test can help to predict whether the cancer cells are sensitive to hormones.

The hormone receptor test measures the amount of certain proteins (called hormone receptors) in cancer tissue. Hormones (such as estrogen and progesterone that naturally occur in the body) can attach to these proteins. If the test is positive, it indicates that the hormone is probably helping the cancer cells to grow. In this case, hormone therapy may be given to block the way the hormone works and help keep the hormone away from the cancer cells (hormone receptors). If the test is negative, the hormone does not affect the growth of the cancer cells, and other effective cancer treatments may be given. Always discuss the results of the hormone receptor test with your physician.

If the test indicates that the hormones are affecting your cancer, the cancer may be treated in one of following ways:

• treating cancer cells to keep them from receiving the hormones they need to grow
• treating the glands that produce hormones to keep them from making hormones
• surgery to remove glands that produce the hormones, such as the ovaries that produce estrogen, or the testicles that produce testosterone

Your physician may prescribe hormone therapies before some cancer treatments or after other cancer treatments. If hormone therapy is given before the primary treatment, it is called neoadjuvant treatment. Neoadjuvant treatments help to kill cancer cells and contribute to the effectiveness of the primary therapy. If hormone therapy is given after the primary cancer treatment, it is called adjuvant treatment. Adjuvant therapy is given to improve the chance of a cure.

With some cancers, patients may be given hormone therapy as soon as cancer is diagnosed, and before any other treatment. It may shrink a tumor or it may halt the advance of the disease. And in some cancer, such as prostate cancer, it is helpful in alleviating the painful and distressing symptoms of advanced disease. Although hormone therapy cannot cure advanced prostate cancer, it will usually shrink or halt the advance of disease, often for years.

Always consult your physician for more information.