Agreement in assessing endometrial pathology: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial

Tibolone histology of the endometrium and breast endpoints study: design of the trial and endometrial histology at baseline in postmenopausal women

OBJECTIVE

To address the endometrial safety of tibolone.

DESIGN

The Tibolone Histology of the Endometrium and Breast Endpoints Study (THEBES) is a randomized, double-blind, parallel-group trial of tibolone compared with continuous combined conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA).

SETTING

Multi-country, multi-center ambulatory care setting.

PATIENT(S)

A total of 5,185 subjects were screened, and biopsies were obtained from 4,446 women.

INTERVENTION(S)

Participants were randomized in a 1:1:2 ratio, to tibolone (1.25 or 2.5 mg/d) or CEE-MPA.

MAIN OUTCOME MEASURE(S)

The one-sided 95% confidence intervals for the incidence of hyperplasia or cancer were evaluated for tibolone compared with CEE-MPA.

RESULT(S)

Endometrial biopsy results at baseline: atrophic (87.29%), inactive (0.25%), proliferative (6.12%), secretory (2.86%), menstrual type (0.40%), and hyperplasia (0.18%). Only subjects with atrophic or inactive endometrium were eligible for this study, and 3% of the women at screening either had no tissue (0.18%) or had an amount of tissue that was insufficient for diagnosis (2.72%). Three thousand two hundred forty postmenopausal women with a mean (+/-SD) age of 54.4 +/- 4.4 years and a mean time since menopause of 4.5 +/- 3.6 years were randomized.

CONCLUSION(S)

The Tibolone Histology of the Endometrium and Breast Endpoints Study is a prospective, randomized clinical trial, designed to provide evidence of the endometrial safety of tibolone compared with estrogen and progestogen. Screening endometrial histology shows a low prevalence of endometrial hyperplasia (0.18%) and no carcinoma.

Endometrial effects of lower doses of conjugated equine estrogens and medroxyprogesterone acetate: two-year substudy results

OBJECTIVE

To determine the endometrial safety of 2 years of treatment with lower doses of continuous combined conjugated equine estrogens (CEE) and medroxyprogesterone acetate (MPA).

DESIGN

Randomized, double-blind, placebo-controlled, multicenter metabolic and osteoporosis substudy of the Women's Health, Osteoporosis, Progestin, Estrogen (Women's HOPE) study.

SETTING

Nineteen study centers across the United States.

PATIENT(S)

Healthy, postmenopausal women (n = 822) with an intact uterus were recruited.

INTERVENTION(S)

Patients received CEE 0.625, CEE 0.625/MPA 2.5, CEE 0.45, CEE 0.45/MPA 2.5, CEE 0.45/MPA 1.5, CEE 0.3, CEE 0.3/MPA 1.5 (all doses mg/day), or placebo for 2 years. Endometrial biopsies were evaluated at baseline and years 0.5, 1, 1.5, and 2 using a centralized protocol.

MAIN OUTCOME MEASURE(S)

Efficacy of lower doses of CEE/MPA in reducing the incidence of endometrial hyperplasia rates associated with unopposed estrogen (E).

RESULT(S)

No cases of endometrial hyperplasia were seen in the four CEE/MPA groups. For the CEE-alone groups, a dose-related increase in incidence rates from 3.17% (CEE 0.3 mg) to 27.27% (CEE 0.625 mg) was seen at 2 years. The number of cases increased from year 1 to year 2. For the CEE-alone groups, the incidence rates and types of hyperplasia diagnosed varied among the pathologists.

CONCLUSION(S)

Two years of treatment with lower doses of CEE/MPA provided endometrial protection comparable to that seen with commonly prescribed doses. These regimens should be considered for postmenopausal women who are candidates for hormone therapy.

Endometrial effects of lower doses of conjugated equine estrogens and medroxyprogesterone acetate

OBJECTIVE

To determine the endometrial safety of lower doses of continuous combined conjugated equine estrogens (CEE) and medroxyprogesterone acetate (MPA).

DESIGN

Randomized, double-blind, placebo-controlled study (the Women's Health, Osteoporosis, Progestin, Estrogen study).

SETTING

Study centers across the United States.

PATIENT(S)

Healthy, postmenopausal women (n = 2,673) with an intact uterus.

INTERVENTION(S)

Patients received CEE 0.625 mg/day, CEE 0.625/MPA 2.5 mg/day, CEE 0.45 mg/day, CEE 0.45/MPA 2.5 mg/day, CEE 0.45/MPA 1.5 mg/day, CEE 0.3 mg/day, CEE 0.3/MPA 1.5 mg/day, or placebo for 1 year. Endometrial biopsies were evaluated at baseline, cycle 6, and year 1 using a centralized protocol.

MAIN OUTCOME MEASURE(S)

Efficacy of lower doses of CEE/MPA in reducing the incidence of endometrial hyperplasia rates associated with unopposed CEE.

RESULT(S)

Endometrial hyperplasia rates ranged from 0 to 0.37% for all CEE/MPA doses. Twenty-nine of the 32 cases of endometrial hyperplasia developed in women who were administered CEE 0.625 mg or CEE 0.45 mg. The incidence of endometrial hyperplasia increased with age for patients administered CEE alone. As expected, there were some inconsistencies among pathologists' ratings in the numbers of hyperplasias and incidence rates for the CEE-alone regimens. There were too few cases of hyperplasia in the combination groups to evaluate consistency among pathologists.

CONCLUSION(S)

One year of treatment with lower doses of CEE/MPA provides endometrial protection comparable to commonly prescribed doses. These regimens may be used by clinicians to individualize hormone replacement therapy in postmenopausal women.