New evidence regarding hormone replacement therapies is urgently required transdermal postmenopausal hormone therapy differs from oral hormone therapy in risks and benefits

Controversies about the safety of different postmenopausal hormone therapies (HTs) started 30 years ago and reached a peak in 2003 after the publication of the results from the Women Health Initiative (WHI) trial and the Million Women Study (MWS) [Writing group for the women's health initiative investigations. Risks and benefits of estrogen plus progestin in healthy postmenopausal women. JAMA 2002;288:321-33; Million women study collaborators. Breast cancer and hormone-replacement therapy in the million women study. Lancet 2003;362:419-27]. The single HT formulation used in the WHI trial for non hysterectomized women-an association of oral conjugated equine estrogens (CEE-0.625 mg/day) and a synthetic progestin, medroxyprogesterone acetate (MPA-2.5 mg/day)-increases the risks of venous thromboembolism, cardiovascular disease, stroke and breast cancer. The MWS, an observational study, showed an increased breast cancer risk in users of estrogens combined with either medroxyprogesterone acetate (MPA), norethisterone, or norgestrel. It is unclear and questionable to what extent these results might be extrapolated to other HRT regimens, that differ in their doses, compositions and administration routes, and that were not assessed in the WHI trial and the MWS. Significant results were achieved with the publication of the WHI estrogen-only arm study [Anderson GL, Limacher M, Assaf AR, et al. Effects of conjugated equine estrogen in postmenopausal women with hysterectomy: the Women's Health Initiative randomized controlled trial. JAMA 2004;291:1701-1712] in which hormone therapy was reserved to women who had carried out hysterectomy. What emerged from this study will allow us to have some important argument to develop.     

The woman patient after WHI

An epidemic of fear and distrust has infected women (and physicians) after publication of the Women's Health Initiative (WHI). The overinflated negative data emerging from the oestroprogestinic arm of WHI have frightened women and gave rise to the most difficult emotions to cope with. Keywords such as cancer, death and hormones combined together, have potentiated an avoidant attitude towards hormonal therapy (HT) driven more emotionally than rationally. This negative aura has not been dissipated by the positive data from the oestrogen-only arm of WHI. This paper will discuss: women's different emotional reactions to and coping strategies for HT-related fear after WHI; the communication skills physicians should use in focusing on positive messages emerging from WHI; predictors of current HT use; the meaning of the higher use of HT in postmenopausal highly-educated women and women gynaecologists; the importance of increasing healthy life-styles as a taking of responsibility towards aging by every woman; shifting from passivity to active sharing of the decision making process with the caring physician; and the use of an individually tailored HT, when appropriate, as part of an active strategy in the pursuit of a longer health expectancy.     

Lessons to be learned from animal studies on hormones and the breast

The relation of hormone use by postmenopausal women to breast cancer risk has been controversial and unclear. A recent large randomized trial, the Women's Health Initiative (WHI) and a large observational study (Million Women Study) provided somewhat conflicting answers. The WHI found an increased incidence of breast cancer among women given hormone therapy (conjugated equine estrogen plus medroxyprogesterone acetate) but no increase in those given estrogen only therapy (conjugated equine estrogen alone). Whereas, the Million Women Study found an increased breast cancer risk among the estrogen plus progestin and the estrogen only users. This review brings comparative perspective to the issue of the effects of estrogen plus progestin versus estrogen only effects on breast cancer and is focused particularly on nonhuman primates. Although data from rodents is mixed, studies of monkeys suggest that estrogen only treatment has little or no effect on breast cell proliferation, and by inference, on breast cancer risk. On the other hand, data from both mouse and monkey studies strongly support the conclusion that the co-administration of a progestogen with an estrogen markedly increases breast cell proliferation and the potential for breast cancer promotion.     

Hormone therapy and coronary heart disease in young women

OBJECTIVE: Because the Women's Health Initiative randomized controlled trial (WHI RCT) primarily studied older women, it is unresolved whether hormone therapy might prevent coronary heart disease in younger women. Given the similarity between our UK General Practice Research Database (GPRD) study of older women and the WHI RCT, the GPRD methodology was used to study a cohort of younger women. DESIGN: Women ages 50 to 55 years were investigated using data from the GPRD to simulate the WHI RCT in a manner similar to our initial study of older women. This study compared 30,102 unexposed and 20,654 exposed women treated with conjugated estrogens and norgestrel. RESULTS: Myocardial infarction was not altered significantly by hormone therapy (adjusted hazard ratio 0.91; 95% CI, 0.69-1.20). Stroke, venous thromboembolic events, breast cancer, and hip fracture were similar to both the GPRD study of older women and the WHI RCT. Although death was decreased in the total cohort, similar to older women, it was not altered significantly in a subset without missing covariate data. CONCLUSION: The similar results of the GPRD studies in younger and older women and between the GPRD and the WHI RCT suggest that hormone therapy does not prevent coronary heart disease in younger postmenopausal women. This study also demonstrates that investigation using a primary care electronic medical record database can expand the generalizability of findings from an RCT.     

Estrogen affects post-menopausal women differently than estrogen plus progestin replacement therapy

BACKGROUND: In the Women's Health Initiative Randomized Controlled Trial (WHI RCT), estrogen-only treatment compared with combined estrogen-progestin treatment resulted in less coronary artery disease, no increase in breast cancer and no reduction in colorectal cancer. Since we previously reasonably replicated the combined estrogen-progestin WHI RCT using the UK General Practice Research Database (GPRD), estrogen-only treatment was investigated using a similar methodology. METHODS: This GPRD study simulated the estrogen-only WHI RCT of women who had undergone a hysterectomy except for randomization. The primary analysis examined 11 572 unexposed and 6890 Exposed women (aged 55-79) treated with conjugated equine estrogen and was compared with the combined estrogen-progestin GPRD study. RESULTS: At baseline, women with a hysterectomy exhibited more cardiovascular disease than those with an intact uterus. In the estrogen-only GPRD study, adjusted hazard ratios (HRs) were 0.50 (0.38-0.67) for myocardial infarction (MI), 1.13 (0.91-1.41) for breast cancer, and 1.18 (0.72-1.92) for colorectal cancer. Compared to the HRs in the estrogen-progestin GPRD study, the estrogen-only results are significantly lower for MI and breast cancer and higher for colon cancer, a pattern similar to the WHI RCT study comparisons. CONCLUSIONS: This study confirms that post-menopausal women in the overall population respond differently to estrogen-only treatment compared with estrogen-progestin treatment, due to different hormone regimens and/or increased cardiovascular disease in hysterectomized women.     

Breast cancer risk in the WHI study: the problem of obesity

In the climacteric, about 40% of the women have occult breast tumors the growth of which may be stimulated by hormones. Many genetic, reproductive and lifestyle factors may influence the incidence of breast cancer. Epidemiological data suggest that the increase in the relative risk (RR) of breast cancer induced by hormone replacement therapy (HRT) is comparable with that associated with early menarche, late menopause, late first birth, alcohol consumption, etc. One of the most important risk factors is obesity which exceeds the effect of HRT by far, and in overweight postmenopausal women the elevated risk of breast cancer is not further increased by HRT. As in the WHI study the majority of women was overweight or obese, this trial was unsuitable for the investigation of breast cancer risk. In the women treated with an estrogen/progestin combination, the RR of breast cancer rose only in those women who have been treated with hormones prior to the study, suggesting a selection bias. In the women not pretreated with hormones, it was not elevated. In the estrogen-only arm of the WHI study, there was no increase but a steady decrease in the RR of breast cancer during 6.8 years of estrogen therapy. This result was unexpected, as estrogens are known to facilitate the development and growth of breast tumors, and the effect is enhanced by the addition of progestins. Obese women are at high risk to develop a metabolic syndrome including insulin resistance and hyperinsulinemia. In postmenopausal women, elevated insulin levels are not only associated with an increased risk for cardiovascular disease, but also for breast cancer. This might explain the effects observed in both arms of the WHI study: HRT with relative low doses of estrogens may improve insulin resistance and, hence, reduce the elevated breast cancer risk in obese patients, whereas this beneficial estrogen effect may be antagonized by progestins. The principal options for the reduction of breast cancer risk in postmenopausal women are the prevention of overweight and obesity to avoid the development of hyperinsulinemia, the medical treatment of insulin resistance, the use of low doses of estrogens and the reduction of exposure to progestins. The latter might include long-cycles with the sequential use of appropriate progestins every 3 months for 14 days. There are large inter-individual variations in the proliferative response to estrogens of the endometrium. Control by vaginalsonography and progestin challenge tests may help to identify those women who may be candidates for low-dose estrogen-only therapy.     

Hormone use and patient concerns after the findings of the Women's Health Initiative

OBJECTIVE: To assess behaviors and concerns related to hormone therapy after the findings of the Women's Health Initiative (WHI). DESIGN: A survey was mailed to a random sample of 1,200 women identified through the pharmacy database as taking one of two estrogen + progestogen therapies (EPT) during the 6-month period before the publication of WHI findings. Questions included hormone use history, changes in usage, an assessment of symptoms, symptom changes, health behavior changes, use of alternative therapies, and demographics. RESULTS: The response rate was 70%, with women in their 60s and those receiving hormone therapy for 5 or more years were more likely to respond (P < 0.05). The majority had started hormones for symptom relief (69%) and expected to continue use. Many reported discontinuation (63%) or modifying their medication (18%). Half of these women stopped then restarted, the other half changed products. Women in their 50s were more likely to remain on hormones than older women (P < 0.01), and those taking ethinyl estradiol and norethindrone acetate were more likely to remain on their medication than those on conjugated estrogens (43% vs 29%, P < 0.01). Little change was reported in exercise and 19% increased their calcium intake. Patient concerns fell into five major categories: long-term effects, symptom control, breast cancer risk, bone health, and cognitive function. CONCLUSIONS: Women seem to be heeding the warnings about hormones but remain concerned about the potential long-term sequelae and symptom control. More research is needed to identify safer approaches to symptom relief and to address the concerns expressed.     

Potential age-dependent effects of estrogen on neural injury

In 2000, approximately 10 million women were receiving hormone replacement therapy (HRT) for alleviation of menopausal symptoms. A number of prior animal studies suggested that HRT may be neuroprotective and cardioprotective. Then, in 2003, reports from the Women's Health Initiative (WHI) indicated that long-term estrogen/progestin supplementation led to increased incidence of stroke. A second branch of the WHI in women with prior hysterectomy found an even stronger correlation between estrogen supplementation alone and stroke incidence. Follow-up analyses of the data, as well as data from other smaller clinical trials, have also demonstrated increased stroke severity in women receiving HRT or estrogen alone. This review examines the studies indicating that estrogen is neuroprotectant in animal models and explores potential reasons why this may not be true in postmenopausal women. Specifically, age-related differences in estrogen receptors and estrogenic actions in the brain are discussed, with the conclusion that animal models of disease must closely mimic human disease to produce clinically relevant results.     

HRT, osteoporosis and regulatory authorities Quis custodiet ipsos custodes?

HRT has been widely used for the relief of menopausal symptoms and the prevention and treatment of post-menopausal osteoporosis. However, following the publication of the Women's Health Initiative (WHI) and the Million Women Study (MWS), regulatory authorities issued an urgent safety restriction on HRT use in preventing post-menopausal osteoporosis, recommending that it now be considered a second-line treatment. Are such recommendations justified? Treatments for osteoporosis, in women with increased future risk for fractures but who have not yet developed the disease, should prevent all types of osteoporotic fractures. Of the available therapies, none other than HRT has been clearly demonstrated to prevent hip fractures in such women. Thus, HRT should be recommended as first-line treatment for osteoporosis prevention. Potential risks of HRT, such as increased development of breast cancer and increased thromboembolism, have long been known. The WHI showed risks in less than 0.3% of women studied, and the MWS appears to have overestimated the risk of breast cancer. Thus, no new safety issues have been identified, and the regulatory authorities may have misinterpreted the data from these recent studies. When given for the correct indications, HRT is of major benefit to many women.     

A new combination of conjugated equine oestrogens and medroxyprogesterone for treatment of climacteric complaints

Thirty-four post-menopausal women with climacteric complaints were given conjugated equine oestrogens (1.25 mg/day) for 21 days followed by 2 days without hormones and then 5 mg medroxyprogesteroneacetate daily for 5 days. The present trial was designed to study effects on vasomotor symptoms, bleeding patterns and endometrial histopathology. Vasomotor disturbances were completely relieved. No recurrence of symptoms was recorded in the oestrogen-free week. Withdrawal bleedings were regular and slight, which was a positive experience for those women who had previously been treated with other oestrogen-progestogen regimens. In most patients inactive or weak secretory endometrial epithelium was found during treatment. Two women developed differing degrees of hyperplasia after 2.5 and 3 yr, respectively. This fact emphasizes the necessity of adding progestogens for at least 10 days each month even if the oestrogens and progestogens are administered separately. It may also be wise to perform an endometrial biopsy when sex hormones are administered on a long-term basis.     

Interactions between melatonin and estrogen may regulate cerebrovascular function in women: clinical implications for the effective use of HRT during menopause and aging

A number of clinical trials associated with the Women's Health Initiative (WHI) have assessed the potential benefits of hormone replacement therapy (HRT) for protection against the development of cardiovascular disease and memory loss in menopausal women. The results of the WHI Memory Study suggest that HRT increases the risk of stroke and dementia in menopausal women. This finding has called into question the results of hundreds of basic science studies that have suggested that estrogen could protect brain cells from damage and improve cognition. A number of researchers have argued that inappropriate formulation, improper dosing, a limited study population, and poor timing of administration likely contributed to the reported findings from the clinical trial. Regarding appropriate formulation, it has been suggested that interactions between estrogen and other hormones should be considered for further investigation. A review of the literature has led us to conclude that a thorough investigation into such hormonal interactions is warranted. We hypothesize that the increased risk of cerebrovascular disease observed in menopausal women may, in part, be due to changes in the circulating levels of melatonin and estrogen and their modulatory affects on many relevant endothelial cell biological activities, such as regulation of vascular tone, adhesion to leukocytes, and angiogenesis, among others. Our hypothesis is supported by numerous studies demonstrating the reciprocal inhibitory effects of melatonin and estrogen on vascular tone, neuroprotection, and receptor expression. We believe that a thorough analysis of the distribution, localization, expression, quantification, and characterization of hormonal receptor subtypes, as well as changes in structural morphology in diseased and normal, healthy cerebrovascular tissue, will substantially aid in our understanding of the effects of HRT on the cerebrovascular circulation. The application of new molecular biological techniques such as tissue microarray analysis, gene and protein arrays, and multi-photon confocal microscopy may be of tremendous benefit in this regard.     

Issues to debate on the Women's Health Initiative: failure of estrogen plus progestin therapy for prevention of breast cancer risk

Several studies on hormone replacement therapy (HRT) in the USA have been published. They revealed that the risk of breast cancer is increased with HRT more than with estrogen alone (ERT). A progestin has been given with each dose of ERT, as was the case in the Women's Health Initiative (WHI) study. The results of studies in Europe show similar trends. The increased risk of breast cancer in the WHI study was significantly higher only in women who had used HRT for several years before entering the study. The study was non-blind in 3444 cases, i.e. 40.5% of women in the estrogen plus progestin group and 6.8% in controls. If the women in the HRT group had more mammographic examinations it could change the validity of the results of the study. Estradiol-containing drugs have now been added to the list of carcinogens and the packages of these drugs have warning labels. The results of the WHI study do not support this labelling. The results of the WHI study show that the administration of HRT increases the risks of stroke and pulmonary embolism. It is reasonable to think that in the case of bleeding, at least at weekends in nursing homes (when staff levels may be low) patients were immobilized in their beds. Immobilization among women on HRT could have been more dangerous than the HRT itself. Progestins need to be delivered to the endometrium in a manner that will have the least effect on the breast. Systemic administration can be replaced by releasing progestin locally in the uterine cavity. Endometrial protection with a levonorgestrel-releasing intra-uterine system (IUS) is well tolerated. The high hepatic concentrations of estrogens given orally could be avoided by transdermal administration. New studies should be planned to reflect the situation in clinical practice. The time to start HRT in healthy menopausal women is between the ages of 45 to 55 years.     

Issues to debate on the Women's Health Initiative (WHI) study. Hormone replacement therapy: an epidemiological dilemma?

In July 2002 the data of the prematurely stopped Estrogen plus Progestin study of the Women's Health Initiative (WHI) were presented in the Journal of the American Medical Association. The results of the Heart and Estrogen/Progestin Replacement Study (HERS/HERS II) were published in the same issue. The results of WHI for healthy postmenopausal women often are interpreted to be in analogy with the HERS/HERS II results for postmenopausal women with established coronary heart disease. As a result of HERS/HERS II and WHI, use of HRT in general became questionable. This is an unjustified judgement of HRT in general. This synoptic review and criticism of both studies will show the methodological weaknesses and their consequences and the reasons for limited generalizability of the study results from WHI and HERS/HERS II on normal HRT users.     

The effect of type and dose of oestrogen on the blood pressure of post-menopausal women

Evidence from two groups of post-menopausal women who were randomly allocated to be treated with either conjugated equine oestrogens or piperazine oestrone sulphate demonstrates that the two oestrogens produce markedly different effects on blood pressure. The conjugated equine oestrogens appear to produce no significant change in either systolic or diastolic blood pressure whereas piperazine oestrone sulphate produced a significant fall in both systolic and diastolic blood pressure. This finding is discussed in relationship to the known causes for a change in cardiovascular response to oestrogen and several hypotheses are put forward.     

Raloxifene lowers serum lipoprotein(A) in healthy postmenopausal women: a randomized, double-blind, placebo-controlled comparison with conjugated equine estrogens.

OBJECTIVE: Long-term postmenopausal estrogen replacement therapy lowers the risk of osteoporotic fractures and coronary artery disease but increases the risk of endometrial cancer and probably breast cancer. Raloxifene, a nonsteroidal estrogen receptor ligand, seems to have a tissue-specific antiestrogenic action on endometrium and breast and the desired estrogenic action on bone and lipid metabolism. The purpose of this study was to investigate the effects of 24-month treatment with orally administered raloxifene in two doses (60 mg and 150 mg daily) and conjugated equine estrogens in a standard oral dose (0.625 mg daily) on serum lipoprotein(a) [Lp(a)], an independent risk factor for coronary artery disease, in healthy postmenopausal women who had undergone hysterectomy. DESIGN: A randomized, double-blind, placebo-controlled study was performed with 56 women. RESULTS: In the placebo group serum Lp(a) levels did not change throughout the study. After 6 months, serum Lp(a) was significantly reduced versus baseline in the raloxifene 150 (-17%; p = 0.003) and conjugated equine estrogens (-26%; p = 0.003) groups, but this reduction was significantly different from placebo only in the conjugated equine estrogens group. At 12 and 24 months, serum Lp(a) levels were significantly lowered versus baseline in all active treatment groups. However, these reductions were significantly different from placebo only in the raloxifene 150 and conjugated equine estrogens groups. After 24 months, serum Lp(a) was reduced versus baseline with 30% (p = 0.001) in the raloxifene 150 group and 35% (p = 0.001) in the conjugated equine estrogens group. CONCLUSIONS: Long term raloxifene treatment significantly lowers serum Lp(a) levels in postmenopausal women and thus might reduce the risk of coronary artery disease.