Study Suggests Schedule for Gyn Exams in Women on Tamoxifen

SAN ANTONIO--Gynecologic evaluation of women taking prophylactictamoxifen (Nolvadex) should be restricted to patients with endometrialthickening that exceeds 8 mm and possibly to premenopausal womenwith amenorrhea, a British study suggests.

Atypical hyperplasia occurred in 10 of 61 women on tamoxifen,compared with none of 50 treated with placebo. Each case of atypiawas associated with endometrial thickening greater than 8 mm,Dr. Andreas Makris reported at the San Antonio Breast Cancer Symposium.

The patients constituted a subset of 111 consecutive postmenopausalwomen in a large randomized study of tamoxifen in women at increasedrisk for breast cancer. Those women taking tamoxifen had beenon the therapy for at least 3 months.

The 61 women on tamoxifen also had a significantly higher uterinevolume and mean endometrial thickness than those on placebo, andthey had a higher incidence of endometrial proliferation and polyps(see table).

All patients in the study have one or more risks for breast cancer,said Dr. Makris, a research fellow at the Royal Marsden Hospital,London. Those randomized to tamoxifen receive 20 mg/day, and regulargynecologic assessments have been performed since 1988. To date,2,300 patients have been enrolled, about two thirds of whom arepremenopausal.

A separate analysis of all 2,300 patients revealed 88 postmenopausalwomen who had endometrial thickening that exceeded 8 mm: 66 ontamoxifen and 22 on placebo. A substudy of those women showedno effect from therapy to reduce endometrial thickness. The studyinvolved 48 patients who were given norethisterone at a dose of2.5 mg/day for 21 days in each 28-day cycle. Three courses oftreatment caused no reduction in endometrial thickness in thesepatients, 42 of whom were on tamoxifen.

"Gynecologic evaluation of women at high risk for breastcancer who are being treated with tamoxifen should be restrictedto those who have endometrial thickening of greater than 8 mm,"Dr. Makris concluded. "Premenopausal women with amenorrheawho are treated with tamoxifen may also be at increased risk,"he added, since they may become prematurely menopausal.