Effects of long-term estrogen replacement therapy. II. Neoplasia

Am J Obstet Gynecol. 1979 Mar 1;133(5):537-47. doi: 10.1016/0002-9378(79)90289-8.

Abstract

Two groups of hypoestrogenic women are analyzed by retrospective comparison. Patients were observed by a single group of physicians for at least five years -- 301 patients treated with replacement estrogen and 309 untreated patients. Of each group, 207 women had uteri in situ. Incidence figures for neoplasia (gynecologic, breast, and all sites) were compared between the two groups and with the Third National Cancer Survey, yielding a risk ratio for the development of adenocarcinoma of the endometrium among estrogen-treated women of 3.8 and 9.3, respectively. There was no increase among any other malignancies. The addition of synthetic progestin to estrogen therapy provided significant protection against the likelihood of developing endometrial cancer and did not reduce previously reported metabolic benefits of estrogen treatment. Data pertaining to estrogen use and details of the patients with endometrial carcinoma are presented.

PIP: The effects of long-term estrogen replacement therapy upon neoplastic diseases were studied in 301 treated patients and 309 untreated patients. 207 women of each group had uteri in situ. Incidence figures for neoplasia were compared between the 2 groups and with the Third National Cancer Survey, yielding a risk ratio for the development of adenocarcinoma of the endometrium among estrogen-treated women of 3.8 (p .05) and 9.3, respectively. The addition of synthetic progestin to estrogen therapy provided significant (p .001) protection against the likelihood of developing endometrial cancer and did not reduce previously reported metabolic benefits of estrogen treatment. The data did not show an increased incidence of breast cancer among estrogen treated women, even with higher dosages or long-term therapy. It is recommended that estrogen therapy should be instituted whenever appropriate indications are present and no major contraindications exist; estrogen should be administered in the lowest dosage and duration that can adequately treat the indication for its use. Estrogens should probably be administered in cyclic fashion, especially if the uterus is in place, with sequentially added progestin.

Publication types

  • Comparative Study

MeSH terms

  • Adenocarcinoma / chemically induced*
  • Adult
  • Breast Neoplasms / epidemiology
  • Estrogens / administration & dosage
  • Estrogens / adverse effects
  • Estrogens / therapeutic use*
  • Estrogens, Conjugated (USP) / therapeutic use
  • Female
  • Genital Neoplasms, Female / epidemiology*
  • Humans
  • Middle Aged
  • North Carolina
  • Progestins / therapeutic use
  • Uterine Neoplasms / chemically induced*

Substances

  • Estrogens
  • Estrogens, Conjugated (USP)
  • Progestins