Related Pages Breast Cancer Home Page 1 NCI's gateway for information about breast cancer. Aromatase Inhibitors 2 A collection of information about aromatase inhibitors, a hormone therapy used in the treatment of some women with breast cancer.

Adapted from the NCI Cancer Bulletin, vol. 3/no. 37, Sept. 26, 2006 (see the current issue ³).

"Our results may represent a departure from the standard management of advanced breast cancer with hormonal therapy that has been used for the last two decades," wrote Dr. John P.A. Ioannidis of the University of Ioannina School of Medicine and colleagues in the Sept. 20, 2006, Journal of the National Cancer Institute (see the journal abstract). "The standard of care may need to be reconsidered."

The AIs reduced the risk of death by 13 percent, which translates to about five months more life in women whose median survival is projected to be 40 months. Though they may produce more hot flashes, AIs are generally more tolerable than tamoxifen and also improve quality of life.

In an accompanying editorial, Drs. Catherine H. Van Poznak and Daniel F. Hayes of the University of Michigan agree that AIs are the drug of choice for women with endocrine-responsive metastatic breast cancer, without ruling out some use of tamoxifen. They cite surveys of oncology practice patterns which show that only about half of these women will receive AIs as adjuvant therapy, despite a recent recommendation by the American Society of Clinical Oncology ⁴.

Glossary Terms

Additional cancer treatment given after the primary treatment to lower the risk that the cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or biological therapy.

A drug that prevents the formation of estradiol, a female hormone, by interfering with an aromatase enzyme. Aromatase inhibitors are used as a type of hormone therapy for postmenopausal women who have hormone-dependent breast cancer.

Describes cells that have a receptor protein that binds the hormone estrogen. Cancer cells that are estrogen receptor positive may need estrogen to grow, and may stop growing or die when treated with substances that block the binding and actions of estrogen. Also called ER+.

A statistics term. The middle value in a set of measurements.

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with the standard of care. Also called best practice and standard therapy.

A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.