What are aromatase inhibitors?
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.
Aromatase inhibitors (AIs) are a class of drugs that block the activity of the enzyme aromatase. Aromatase is responsible for the conversion of androgens (male hormones) into estrogen (female hormones) in various tissues, including the ovaries, adrenal glands, and adipose tissue. In postmenopausal women, the majority of estrogen is produced through this conversion process rather than from the ovaries.
AIs are primarily used in the treatment of hormone receptor-positive breast cancer in postmenopausal women. These tumors are stimulated to grow by estrogen. By inhibiting aromatase and reducing estrogen levels in the body, AIs help to slow down or inhibit the growth of hormone-sensitive breast cancers.
There are two main types of aromatase inhibitors:
Non-steroidal aromatase inhibitors:
- Anastrozole (brand name: Arimidex)
- Letrozole (brand name: Femara)
Steroidal aromatase inhibitor:
These drugs are typically prescribed for postmenopausal women because in premenopausal women, the ovaries are the primary source of estrogen, and AIs are not effective at reducing ovarian estrogen production.
It’s important to note that the use of aromatase inhibitors is usually part of a comprehensive treatment plan for breast cancer and is determined by the patient’s specific circumstances and the characteristics of the cancer. Like any medication, aromatase inhibitors can have side effects, and patients should discuss potential benefits and risks with their healthcare provider.
