Aromatase inhibitors are a class of medicines that work by blocking the enzyme aromatase, the enzyme that converts androgens into estrogen. Aromatase inhibitors are used in the treatment of breast cancer to reduce levels of circulating estrogen. This means that less estrogen is available to stimulate the growth of estrogen receptor (ER) positive breast cancer cells, slowing or inhibiting the progression of these cancers. Approximately 80% of all breast cancers are ER positive.
Aromatase inhibitors are unable to prevent the ovaries from making estrogen, which means that they are only used to treat breast cancer in postmenopausal women.
There are three aromatase inhibitors: anastrozole, exemestane, and letrozole.
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Source:drugs.com
Anastrozole
Anastrozole is used with other treatments, such as surgery or radiation, to treat early breast cancer in women who have experienced menopause (change of life; end of monthly menstrual periods). This medication is also used in women, who have experienced menopause, as a first treatment of breast cancer that has spread within the breast or to other areas of the body. This medication is also used to treat breast cancer in women whose breast cancer has worsened after taking tamoxifen (Nolvadex). Anastrozole is in a class of medications called nonsteroidal aromatase inhibitors. It works by decreasing the amount of estrogen the body makes. This can slow or stop the growth of many types of breast cancer cells that need estrogen to grow.
Exemestane is used to treat early breast cancer in women who have experienced menopause ('change of life'; end of monthly menstrual periods) and who have already been treated with a medication called tamoxifen (Nolvadex) for 2 to 3 years. This medication is also used to treat breast cancer in women who have experienced menopause whose breast cancer has worsened while they were taking tamoxifen. Exemestane is in a class of medications called aromatase inhibitors. It works by decreasing the amount of estrogen produced by the body. This can slow or stop the growth of some breast tumors that need estrogen to grow.
Letrozole is used treat early breast cancer in women who have experienced menopause (change of life; end of monthly menstrual periods) and who have had other treatments, such as radiation or surgery to remove the tumor. It is also used to treat early breast cancer in women who have experienced menopause and who have already been treated with a medication called tamoxifen (Nolvadex) for 5 years. Letrozole is also used in women who have experienced menopause as a first treatment of breast cancer that has spread within the breast or to other areas of the body or in women whose breast cancer has worsened while they were taking tamoxifen. Letrozole is in a class of medications called nonsteroidal aromatase inhibitors. It works by decreasing the amount of estrogen produced by the body. This can slow or stop the growth of some types of breast cancer cells that need estrogen to grow.
