Breast cancer drug effective for fibroids in women

NEW YORK (Reuters Health) - In premenopausal women with fibroids, the breast cancer drug anastrozole (Arimidex) reduces fibroid size and improves bothersome symptoms, according to results of a prospective study conducted at the Aristotle University of Thessaloniki in Greece.

Fibroid tumors, or uterine leiomyomata, are benign growths in the uterus that can cause pain and bleeding and may eventually require surgical removal.

Dr. Fotios K. Varelas and his associates treated 35 women with fibroid tumors with a very low dose of anastrozole -- 1 milligram per day for 3 cycles of 28 days each.

According to ultrasound scans and imaging studies conducted before treatment, the average fibroid volume was 163 mL, and total uterine volume was 278 mL. By the end of treatment, the research team documented an average 55.7 percent reduction of fibroid volume, and a 29.9 percent reduction in total uterine volume.

The beneficial effect was restricted to women over age 40, the physicians discovered, and the degree of improvement was most pronounced in women with large fibroids.

The women also reported significant decreases in the severity of vaginal bleeding and pelvic pressure or pain.

Varelas and colleagues found that the treatment was “generally well tolerated,” with no serious adverse effects. One woman experienced vaginal dryness, and one had pain during intercourse.

Based on other studies, the researchers think long-term treatment with anastrozole will be safe, but they emphasize that larger, placebo-controlled clinical trials will be required to establish the risk posed by prolonged anastrazole use in premenopausal women.

Anastrozole is typically prescribed for older (postmenopausal) women with breast cancer that is sensitive to estrogen. Anastrozole, and similar drugs, inhibit the enzyme aromatase, which is needed to produce estrogen. The current study suggests that anastrozole, given in such a low dose, acts primarily by blocking estrogens produced by the fibroids.

SOURCE: Obstetrics and Gynecology September 2007.