Breast Cancer Drug May Ease Endometriosis

Femara May Offer Alternative in Endometriosis Treatment

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Feb. 13, 2004 -- A drug used to help prevent breast cancer from coming back may also ease the pain and suffering of endometriosis in women who can't get relief from other treatments.

A new study shows the drug Femara, in combination with progestin, significantly slowed the progression of endometriosis as well as reduced the pain associated with the disease.

Endometriosis affects about 10%-15% of women of reproductive age. It occurs when tissue similar to the lining of the uterus grows in other places in the body. Depending on its severity, the disease may cause little or no symptoms or lead to severe pelvic pain and infertility.

There is no cure for endometriosis. Treatment options include surgery to remove the excess tissue or hysterectomy and/or drugs that can drastically decrease the production of estrogen to postmenopausal levels. Occasionally, oral contraceptives or progestins are given to help alleviate the pain of endometriosis.

Researchers say the problem with surgical treatments is that endometriosis often comes back after surgery. Drugs used to treat endometriosis also have unpleasant side effects such as bone loss and may only be used for limited periods of time.

New Option for Endometriosis Treatment?

In this study, published in the February issue of Fertility and Sterility, researchers looked at the possibility of using Femara as an alternative treatment in premenopausal women with endometriosis.

Femara is a type of drug known as an aromatase inhibitor. Aromatase inhibitors work to prevent breast cancer recurrence by reducing the production of estrogen in the body.

Researchers say aromatase, which helps produce estrogen, is also found in the endometrial tissue of women with endometriosis.

"Endometriosis is an estrogen-dependent disease, so estrogen for endometriosis is like fuel for fire. We need to attack the root problem -- the aromatase -- in order to eliminate this cycle, halt the local production of estrogen, and treat women with this disease," says researcher Serdar Bulun, MD, chief of the division of reproductive biology research at Northwestern Memorial Hospital in Chicago, in a news release.

To test that theory, researchers looked at the effects of six months of treatment with Femara, along with progestin to reduce potential hormone-related side effects, in 10 women who had previously been treated for endometriosis with surgery or drugs with unsatisfactory results. The women also took calcium citrate and vitamin D to help prevent bone loss.


Researchers evaluated the women's pelvic pain and performed laparoscopy, a minimally-invasive surgical procedure to visualize the pelvic area, before and after the treatment.

The study showed that none of the women had evidence of endometriosis by the end of the study, as indicated by the second laparoscopy. Pelvic pain was also significantly reduced in nine out of 10 women who had not responded previously to other treatments.

The most commonly reported side effects were irregular bleeding and mild hot flashes. No significant change in bone density (strength) was detected.

"This study demonstrates the potential of aromatase inhibitors to significantly and rapidly reduce disease severity and pain, offering women a new and more effective way of suppressing endometriosis with fewer side effects," says Bulun. "These results appear extremely promising and constitute the rationale for further investigation of this regimen as a first-line treatment for endometriosis."

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SOURCES: Ailawadi, R. Fertility and Sterility, February 2004; vol 81: pp 290-296. News release, Northwestern Memorial Hospital.
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