Uterine pathology in tamoxifen-treated patients with breast cancer.

In the last 20 years, tamoxifen has become the drug of choice in the treatment of breast carcinoma in both advanced and early stages. Furthermore, the ability of tamoxifen to prevent mammary carcinoma in the contralateral breast has prompted the creation of trials that include healthy patients with an increased risk of developing breast cancer with the purpose of verifying the drug's prophylactic action. As a consequence, a large number of healthy women or women with a long life expectancy are being treated with tamoxifen for long periods, making it crucial to study the possible long-term effects associated with this therapy. A weak estrogen-like effect of tamoxifen on the endometrium has been documented. This is supported by the increased incidence of glandular hyperplasia, polyps, carcinoma, and sarcoma in tamoxifen-treated patients. Some studies have shown that not all endometrial carcinomas arising in tamoxifen-treated patients have the favorable histologic and prognostic features typical of estrogen-associated endometrial cancers. This, in conjunction with the demonstrated carcinogenicity of tamoxifen in some animal models, indicates the need for caution in the use of this drug and makes strict gynecologic surveillance of tamoxifen-treated patients imperative.