Cancer drug plus the Pill relieves endometriosis
US Investigators report, that A drug used to treat and prevent Breast cancer, Arimidex, can significantly reduce the pain of endometriosis when taken daily along with an oral contraceptive.
Endometriosis is a condition in which the endometrium, tissue that normally lines the uterus, grows in other areas of the body, causing pain, irregular bleeding, and frequently infertility.
The tissue growth typically occurs in the pelvic area, outside of the uterus, on the ovaries, bowel, rectum, bladder, and the delicate lining of the pelvis, but it can occur in other areas of the body as well.
Current treatments for endometriosis are ineffective for many women or have dangerous side effects, Dr. Serdar E. Bulun, from Northwestern University in Chicago, and his associates note in the medical journal Fertility and Sterility.
Arimidex inhibits an enzyme, aromatase, involved in estrogen synthesis, and it was recently found that high levels of aromatase are expressed in endometrial tissue of women with endometriosis.
The cause of endometriosis is unknown. However, a number of theories have been proposed. The retrograde-menstruation theory proposes that endometrial cells (loosened during menstruation) may “back up” through the fallopian tubes into the pelvis, where they implant and grow in the pelvic and/or abdominal cavities.
The immune-system theory suggests that a deficiency in the immune system allows menstrual tissue to implant and grow in areas other than the uterine lining. Another theory suggests that the cells lining the abdominal cavity may spontaneously develop endometriosis. A genetic theory proposes that certain families may exhibit predisposing factors that lead to endometriosis.
Once the endometrial cells implant in tissue outside of the uterus, they may become a problem. Each month the ovaries produce hormones that stimulate the cells of the uterine lining to multiply and prepare for a fertilized egg (swell and thicken).
Bulun’s group theorized that Arimidex (generic name, anastrozole) would block aromatase from producing estrogen in the endometrial tissue. An oral contraceptive would prevent the Osteoporosis associated with aromatase inhibitor drugs.
In their study the investigators treated 18 women, who had failed at least two other treatments for endometriosis, with anastrozole and the Alesse oral contraceptive daily for 6 months.
Fourteen of the 15 women who completed the study experienced significant reductions in pelvic pain. By the end of the first month, the average pain score on a 10-point visual scale fell from 8.70 to 6.20, and by the end of 6 months it was 3.20.
Side effects were mild and improved as the trial progressed. The researchers think that with a longer trial, endometriosis pain and side effects might resolve completely.
The one woman who became pregnant experienced no complications and delivered a normal healthy infant.
“This is an exciting new development in the treatment of a condition with only a limited number of treatments available,” the team concludes.
This study was partially funded by AstraZeneca, the maker of Arimidex.
SOURCE: Fertility and Sterility, August 2005.
Revision date: June 14, 2011
Last revised: by Sebastian Scheller, MD, ScD