Prevention of endometrial abnormalities

A comparative 2-year study of the effects of sequential regimens of 1 mg 17beta-estradiol and trimegestone with a regimen containing estradiol valerate and norethisterone on the bleeding profile and endometrial safety in postmenopausal women

OBJECTIVE

To compare the bleeding profiles and endometrial protection of two sequential regimens of 17beta-estradiol (17beta-E2) and trimegestone (TMG) with a sequential estradiol valerate (E2V)/norethisterone (NET) regimen.

STUDY DESIGN

This was a randomized, double-blind, multicenter study conducted in eight countries in healthy, postmenopausal women with an intact uterus. A total of 1218 women were enrolled into the initial 1-year study (13 cycles), and subsequently 531 of these received treatment for a further year (26 cycles). Treatment regimens were 1 mg 17beta-E2 on days 1-14 and 1 mg 17beta-E2/0.125 mg TMG or 1 mg 17beta-E2/0.25 mg TMG on days 15-28, and 1 mg E2V on days 1-16 and 1 mg E2V/1 mg NET on days 17-28.

RESULTS

Mean percentage of women reporting onset of withdrawal bleeding episodes during the week following discontinuation of progestogen was higher in the 1 mg 17beta-E2/0.25 mg TMG group than in the other two treatments, showing a more efficient progestogen effect on the endometrium and good predictability of bleeding onset with this treatment. The mean numbers and average lengths of bleeding episodes were similar in the three treatment groups. Overall, the bleeding profile was more favorable with 1 mg 17beta-E2/0.25 mg TMG than with the lower-dose TMG preparation. Both of the TMG regimens demonstrated a good protective effect on endometrial proliferation, with the 0.25 mg TMG dose showing a lower incidence of proliferative endometrium.

CONCLUSION

The 1 mg 17beta-E2/0.25 mg TMG regimen showed an adequate protection of the endometrium, with an overall favorable bleeding profile.

A study of the control of climacteric symptoms in postmenopausal women following sequential regimens of 1 mg 17beta-estradiol and trimegestone compared with a regimen containing 1 mg estradiol valerate and norethisterone over a two-year period

OBJECTIVE

To compare the efficacy of two sequential 17beta-estradiol (17beta-E2)/trimegestone (TMG) combinations with the sequential estradiol valerate (E2V)/norethisterone (NET) regimen in relieving climacteric symptoms.

STUDY DESIGN

This was a double-blind, randomized, multicenter study conducted among 1218 Caucasian (99%) postmenopausal women with an intact uterus in seven European countries and Israel, over 13 cycles (each of 28 days). Study duration was extended further for 13 cycles, with 531 women receiving treatment for up to 26 cycles. Treatments consisted of 1 mg 17beta-E2 on days 1-14 and 1 mg 17beta-E2/0.125 mg TMG or 0.25 mg TMG on days 15-28, and 1 mg E2V on days 1-16 and 1 mg E2V/1 mg NET on days 17-28.

RESULTS

Rapid and significant reductions in the mean daily number and severity of hot flushes and in the mean daily number of nocturnal sweats were established in most women with 1 mg 17beta-E2/0.25 mg TMG and E2V/NET. These treatments also induced a significant improvement in the quality-of-life assessments.

CONCLUSION

The 1 mg 17beta-E2/0.25 mg TMG regimen provides rapid and effective relief of menopausal symptoms, with a reduction in the number of hot flushes "at least as good as" that of the E2V/NET comparator.

Perimenopausal use of reproductive hormones effects on breast and endometrial cancer

The effect of reproductive hormone use in the form of oral contraception or HRT on endometrial cancer incidence is not caused by simply bias: the epidemiologic studies are consistent; the effect of ERT is large; the biologic rationale cited is a plausible mechanism; and the response to progestin in oral contraception or combined HRT tends to confirm the biologic mechanism. In contrast, it remains unclear whether changes in breast cancer incidence following use of oral contraception and HRT are caused by hormone exposure or to other factors: the results of epidemiologic studies are not entirely consistent, and the smaller relative effect on risk of breast cancer is susceptible to bias and other sources of error. Although the exact nature of the association between repro ductive hormone use and breast cancer incidence is not yet clear, breast cancer is a common neoplasm in older women. Prescribers and users should take this into account in weighing benefits to ensure that unnecessary risks are avoided.

Cell cycle analysis and detection of proliferative cell nuclear antigen of the endometrium after hormone replacement therapy

BACKGROUND

To understand the effect of sequential combined hormone replacement therapy (HRT) on the postmenopausal endometrium.

METHODS

Sonographic endometrial thickness, endometrial histopathology, flow cytometric cell cycle analysis and the level of proliferative cell nuclear antigen (PCNA) were studied.

RESULTS

One hundred and thirty-eight postmenopausal women were enrolled in this study. Among which, 97 women had their endometrium being adequately obtained; the most frequent type of histopathology was normal endometrium (91.8%). Endometrial hyperplasia was found in seven patients (7.2%), including typical simple hyperplasia (n=1, 1%), focal simple hyperplasia (n=5, 5.2%) and complex hyperplasia without atypia (n=1, 1%). The proliferative fractions (PF; S plus G2-M phase) of cells from normal and hyperplastic endometrium of menopausal women after HRT were 8.18 and 8.95%, respectively, which were lower than those from 29 premenopausal women without HRT. The level of PCNA of normal and hyperplastic endometrium in postmenopausal women after HRT was about 80 and 84%, respectively, of that from premenopausal endometrium.

CONCLUSIONS

Our study showed the PF of the cell cycle and the level of PCNA were not increased in the menopausal endometrium under HRT as compared to the premenopausal controls.

Effects of sex steroids on serum lipids and lipoproteins

Cardiovascular disease is the leading cause of death in women but manifests itself primarily in the postmenopausal years. Menopause appears to increase the cardiovascular risk, at least when surgically induced, whereas the effects of the natural menopause are still a matter of debate. Why postmenopausal women apparently lose their natural cardioprotection is not established, but oestrogen deficiency seems to play an important role. Loss of ovarian hormone production at the menopause significantly alters serum lipids and lipoproteins, giving rise to more atherogenic lipid profiles throughout the postmenopausal years, and these changes may in part be responsible for the alleged cardiovascular risk. Postmenopausal hormone replacement therapy, using oral unopposed oestrogens, induces potential favourable effects on lipids and lipoproteins, and epidemiological evidence has established that the risk of cardiovascular mortality is reduced by 40-60% in women receiving postmenopausal oestrogen therapy. Part of this reduction seems to be explained by changes in lipids and lipoproteins. Parenteral administration of oestrogens induces comparable, although less pronounced effects on lipids and lipoproteins, and the possible cardioprotective role of parenteral administration remains obscure. The addition of progestogens to postmenopausal oestrogen therapy is essential for endometrial protection, but progestogens apparently antagonize some of the actions of oestrogens on lipid metabolism. However, the type, the dose, the duration and the route of administration, as well as the potency balance between the oestrogen and the progestogen employed, are important determinants for the ultimate effect on lipid metabolism. With the use of cyclic administration and the lowest possible doses of progestogens, the oestrogenic actions on lipids and lipoproteins can be largely preserved, but the cardioprotective potential of combined oestrogen-progestogen therapy is as yet unknown.

Interaction of ring B unsaturated estrogens with estrogen receptors of human endometrium and rat uterus

The present investigation was undertaken to compare the binding affinities (Ka) of the ring B unsaturated equine estrogens (equilin [Eq], equilenin [Eqn], 17 beta-dihydroequilin [17 beta-Eq], 17 beta-dihydroequilenin [17 beta-Eqn], 17 alpha-dihydroequilin [17 alpha-Eq], and17 alpha-dihydroequilenin [17 alpha-Eqn]) and the classic estrogens (estrone [E1], 17 beta-estradiol [17 beta-E2], and 17 alpha-estradiol [17 alpha-E2]) for estrogen receptors in human endometrium and rat uterus. In both species, the ring B unsaturated estrogens bind with cytosol and nuclear receptors with high affinity (Ka x 10(9) M-1). The relative binding affinities of these estrogens were measured by determining the amount of unlabeled estrogen required to reduce by 50% the specific binding of [3H]17 beta-Eq to endometrial cytosol receptors. The order of activity found was 17 beta-Eq greater than 17 beta-E2 greater than 17 beta-Eqn greater than E1 greater than Eq greater than 17 alpha-Eq greater than 17 alpha-E2 greater than 17 alpha-Eqn greater than Eqn. Essentially the same order of activity was observed when the apparent affinity constants of these estrogens for human and rat cytosol and nuclear receptors were determined by a competitive (inhibition) binding assay. Sucrose density gradient analysis indicated that these estrogens form protein complexes with cytosol and nuclear preparation that sediment at approximately 8S and 4S, respectively. The affinity constants for 17 beta-Eq were approximately two- to six-fold higher than E2 in both species. In a rat uterotropic assay, all nine estrogens were uterotropic. These data indicate that all ring B unsaturated estrogens present in conjugated equine estrogen preparations are biologically active and they express their biologic effects in the human endometrium by mechanisms similar to those described for the classic estrogens.

Sequential use of norethisterone and natural progesterone in pre-menopausal bleeding disorders

Sequential treatment with norethisterone (NET) or natural micronized progesterone (NMP) was administered randomly to 80 consecutive patients attending our clinic because of cycle disorders. The endometrial morphology indicated a need for progestogen therapy in all cases and the endometrium was hyperplastic in half of the women before therapy. Hyperplastic changes disappeared during the first three cycles of treatment with both NET and NMP, the duration of treatment being 6 months. However, the carry-over effect of both progestogens was short: three months after treatment was discontinued a proliferative or hyperplastic endometrial pattern recurred in 24% and 10% of cases, respectively. Whereas NET decreased oestradiol, follicle-stimulating hormone, luteinizing hormone and sex-hormone-binding globulin levels (P less than 0.001) no changes were seen during NMP treatment. High-density-lipoprotein cholesterol and triglyceride levels were also lowered by NET (P less than 0.001-0.02) and there was a slight decrease in phospholipids. NMP treatment induced no changes in serum lipid values and thus offers an alternative form of therapy in premenopausal bleeding disorders.

Compliance considerations with estrogen replacement: withdrawal bleeding and other factors

Withdrawal bleeding and other side effects such as edema, bloating, premenstrual irritability, lower abdominal cramps, dysmenorrhea, and breast tenderness limit compliance with hormonal replacement therapy. Although many of these troublesome side effects can be managed by adjusting the dose or changing the source of the estrogen or progestin components, postmenopausal women view withdrawal bleeding as the most negative factor influencing their decision to use hormonal replacement therapy. Additionally, the potential link between postmenopausal estrogen use and subsequent endometrial hyperplasia and cancer concerns potential users. Cyclic progestins protect the endometrium from hyperplastic changes but may not prevent withdrawal bleeding. Both patient and physician education, including the nature of menopause and the protective role of estrogens in osteoporosis and cardiovascular disease, are critical to improving compliance with hormonal replacement therapy.

Controversies concerning the safety of estrogen replacement therapy

Unopposed estrogen replacement is known to cause endometrial carcinoma in a small percentage of postmenopausal women, but the effects on ovarian and breast tissue remain uncertain. The increased risk of endometrial carcinoma seems to be related to both the dosage and duration of unopposed estrogen treatment. Until very recently, the morbidity and costs that result from the need for endometrial biopsy because of abnormal bleeding and from the need for hysterectomy due to hyperplasia have been ignored, but recent data suggest that they are likely to be considerable. Progestogens are known to protect against endometrial hyperstimulation, but the optimal duration of therapy each month and the maximally protective agent and dose remain to be determined. Estrogen replacement therapy may reduce the risk of arterial disease; however, the comparative effects of the various preparations, as well as their respective mechanisms of action, must be subjected to further study.