Aromatase inhibitors are chemicals that block the production of aromatase, an enzyme that stimulates the production of estrogen in post-menopausal women. Some types of cancerous cells use estrogen for growth. The effects of aromatase inhibitors on breast cancer can be seen in the decreased amount of estrogen produced through a process known as aromatization, and many physicians are recommending aromatase inhibitors hormonal therapy after surgery or radiation to reduce the chance of estrogen-receptor positive breast cancer coming back.
Once a woman has gone through menopause, her ovaries no longer naturally produce estrogen. Some types of breast cancer cells are dependent on the hormone estrogen to grow, and so women who are no longer menstruating can take aromatase inhibitors to block the production of the hormone and possibly reduce the chance of the cancerous cells from growing or spreading. These estrogen-blocking effects of aromatase inhibitors on breast cancer are usually only effective for women who have hormone-receptor-positive breast cancer that is in the early stages of development.
Aromatase inhibitors on breast cancer also produces positive results in some women who have metastatic breast cancer, recurring estrogen receptor-positive breast cancer, as well as in women diagnosed with ovarian cancer or endometriosis. Usually, the effects of the aromatase inhibitors are evident in women who have had surgery to remove tumors or cancerous tissue, or have completed radiation. Aromatase inhibitors are part of a adjuvant hormone therapy recommended by physicians for some women, that will reduce the risk of cancer returning. An oncologist usually prescribes taking tamoxifen, another type of anti-estrogen therapy, for two to five years and then taking an aromatase inhibitor for the following two to five years. Aromatase inhibitors can also be taken immediately after a woman’s initial round of cancer treatment.
As with most medications, there are some side effects of using aromatase inhibitors on breast cancer. This type of hormone therapy can cause osteoporosis and bone thinning because of the removal of estrogen from the body. Hot flashes, joint aches, and fatigue are commonly associated with taking aromatase inhibitors. Some woman experience diarrhea, constipation and even nausea.
There are no studies that show the long-term effects of taking aromatase inhibitors, so women should consult their physicians about the risks associated. Also, aromatase inhibitors are much more expensive than tamoxifen, which has a generic form. Anastrozole, exemestane and letrozole are the chemical names of the three types of inhibitors available.