Hormone and nonhormone therapy for the maintenance of postmenopausal health: the need for randomized controlled trials of estrogen and raloxifene

The role of PKN1 in glioma pathogenesis and the antiglioma effect of raloxifene targeting PKN1

PKN1 (protein kinase N1), a serine/threonine protein kinase family member, is associated with various cancers. However, the role of PKN1 in gliomas has rarely been studied. We suggest that PKN1 expression in glioma specimens is considerably upregulated and positively correlates with the histopathological grading of gliomas. Knocking down PKN1 expression in glioblastoma (GBM) cells inhibits GBM cell proliferation, invasion and migration and promotes apoptosis. In addition, yes-associated protein (YAP) expression, an essential effector of the Hippo pathway contributing to the oncogenic role of gliomagenesis, was also downregulated. In contrast, PKN1 upregulation enhances the malignant characteristics of GBM cells and simultaneously upregulates YAP expression. Therefore, PKN1 is a promising therapeutic target for gliomas. Raloxifene (Ralo), a commonly used selective oestrogen-receptor modulator to treat osteoporosis in postmenopausal women, was predicted to target PKN1 according to the bioinformatics team from the School of Mathematics, Tianjin Nankai University. We showed that Ralo effectively targets PKN1, inhibits GBM cells proliferation and migration and sensitizes GBM cells to the major chemotherapeutic drug, Temozolomide. Ralo also reverses the effect of PKN1 on YAP activation. Thus, we confirm that PKN1 contributes to the pathogenesis of gliomas and may be a potential target for Ralo adjuvant glioma therapy.

Interactions between estradiol, diabetes, and brain aging and the risk for cognitive impairment

The Women's Health Initiative Memory Study reported that older women using conjugated equine estrogens hormone therapy (HT) with or without medroxyprogesterone acetate were at increased risk for probable dementia and smaller brain volumes. These adverse effects were greatest among women who had type 2 diabetes mellitus (T2DM) at baseline or who developed the disease during follow-up. This review summarizes existing literature from randomized trials, observational studies, and preclinical studies to provide a fundamental understanding of the effects of the interaction between T2DM and HT on cognitive and metabolic health changes in brain aging.

Effect of hormone therapy and calcitriol on serum lipid profile in postmenopausal older women: association with estrogen receptor-α genotypes

OBJECTIVE

The aim of this study was to examine the effect of conjugated equine estrogens alone (ET), conjugated equine estrogens + medroxyprogesterone (EPT), calcitriol alone, calcitriol + EPT/ET, or placebo on serum lipid profile and analyze the interaction with estrogen receptor-α gene single nucleotide polymorphisms (ESR-α SNPs) on the response to therapy.

METHODS

A total of 489 postmenopausal women older than 65 years were enrolled into a 3-year double-blind, placebo-controlled clinical trial.

RESULTS

In both intent-to-treat and complier (>80% adherent) analysis, there was a significant increase in serum high-density lipoproteins and a significant decrease in serum low-density lipoproteins (LDLs) and the LDL/high-density lipoprotein ratio in all hormone treatment groups compared with placebo (P < 0.05). However, serum triglycerides and very low-density lipoproteins increased in the EPT and ET + calcitriol groups versus placebo (P < 0.05). ESR-α SNPs PvuII and XbaI seemed to have a significant effect on the response to treatment. Genotypes containing the p allele showed a significantly greater decrease in serum cholesterol and very low-density lipoprotein than those having the P allele in the ET + calcitriol group (P < 0.05), and those with the x allele had a significantly greater decrease in serum cholesterol in the hormone therapy + calcitriol group at the end of 3 years versus the X allele, and a greater decrease in serum LDL in alleles x versus the X in the ET + calcitriol group (P < 0.05).

CONCLUSIONS

ET with or without progesterone had a favorable effect on lipid profile in postmenopausal older women, and this was dependent on estrogen receptor SNPs--PvuII and XbaI. However, this interaction with ESR-α SNPs needs to be confirmed in larger studies.

Correlation of bone mineral density with biochemical markers in post menopausal women

To evaluate the magnitude of bone loss in postmenopausal women and to study the effect of a selective estrogen Receptor Modulator, raloxifene, on bone loss by quantitative ultrasound of calcaneus and serum bone specific alkaline phosphatase (BAP). Postmenopausal women with ostesopenia/osteoporosis were assigned randomly to receive placebo (n=30) or raloxifene (60mg/d, n=30) with calcium (500mg/day) and vitamin D (250 IU/day). The bone mineral density (BMD) and BAP levels were measured at the beginning of therapy and six months later. They were subjected to statistical analysis (t test, p value) using SPSS statistical package. 70% of postmenopausal women suffered from osteopenia/osteoporosis. After raloxifene therapy, there was improvement in the BMD but this was not statistically significant (p>0.05). There was a fall in the value of serum BAP by 26.6% (p<0.05). Raloxifene has a favourable effect on bone turnover as evident from changes in BMD and a significant fall in serum BAP.

Effect of teriparatide [rhPTH(1-34)] on BMD when given to postmenopausal women receiving hormone replacement therapy

The effects of teriparatide when given in combination with HRT were studied in postmenopausal women with low bone mass or osteoporosis. The data provide evidence that the adverse event profile for combination therapy with teriparatide + HRT together is consistent with that expected for each treatment alone and that the BMD response is greater than for HRT alone.

INTRODUCTION

Teriparatide [rhPTH(1-34)], given as a once-daily injection, activates new bone formation in patients with osteoporosis. Hormone replacement therapy (HRT) prevents osteoporosis by reducing bone resorption and formation. Combination therapy with these two compounds, in small clinical trials, increased BMD and reduced vertebral fracture burden. The purpose of this study was to determine whether teriparatide provided additional effect on BMD when given in combination with HRT.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled study was conducted in postmenopausal women with either low bone mass or osteoporosis. Patients were randomized to placebo subcutaneous plus HRT (n = 125) or teriparatide 40 microg/day (SC) plus HRT (TPTD40 + HRT; n = 122) for a median treatment exposure of 13.8 months. Approximately one-half of the patients in each group were pretreated with HRT for at least 12 months before randomization. Patients received 1000 mg calcium and 400-1200 IU of vitamin D daily as oral supplementation. BMD was measured by DXA.

RESULTS

Compared with HRT alone, TPTD40 + HRT produced significant (p < 0.001) increases in spine BMD (14% versus 3%), total hip (5.2% versus 1.6%), and femoral neck (5.2% versus 2%) at study endpoint. BMD, in whole body and ultradistal radius, was higher, and in the one-third distal radius was lower, in the combination therapy but not in the HRT group. Serum bone-specific alkaline phosphatase and urinary N-telopeptide/Cr were increased significantly (p < 0.01) in the women receiving TPTD40 + HRT compared with HRT. A similar profile of BMD and bone markers was evident in both randomized patients as well as in subgroups of patients not pretreated or pretreated with HRT. Patients tolerated both the treatments well. Nausea and leg cramps were more frequently reported in the TPTD40 + HRT group.

CONCLUSIONS

Adding teriparatide, a bone formation agent, to HRT, an antiresorptive agent, provides additional increases in BMD beyond that provided by HRT alone. The adverse effects of teriparatide when added to HRT were similar to the adverse effects described for teriparatide administered alone. Whether teriparatide was initiated at the same time as HRT or after at least 1 year on HRT, the incremental increases over HRT alone were similar.

Postmenopausal hormone therapy and breast cancer: What is the problem?

Observational studies provide evidence that breast cancer risk is increased with long-term oral use of postmenopausal estrogen replacement therapy (ET). Various large cohort studies have shown that the addition of a progestogen in combined hormone replacement therapy (EPT) increases this risk further. Prospective, randomized controlled trials have confirmed this for the continuous combined regimen. So, why not tell our patients, "Stop using ET and EPT, it is dangerous to your health!"? The answer is: there are too many problems to allow such an oversimplified, definite statement. What is the problem? There is more than one! The problems are as follows: In conclusion, we have a problem as we cannot formulate any general advice that holds for the majority of European postmenopausal women due to lack of consistency, lack of biological plausibility, and lack of relevance of randomized clinical trial data to our daily practical work. So, we have a problem and not a firm basis for undisputable statements.

Is the WHI relevant to HRT started in the perimenopause?

The Women's Health Initiative (WHI) hormone replacement therapy (HRT) estrogen plus progestin (E+P) and estrogen-only arms are part of a large NIH-sponsored randomized controlled trial (RCT). Both arms were terminated prematurely after 5 and 8 yr, respectively. The E+P arm showed non-statistically significant increased incidences of cardiovascular events and breast cancer, whereas the E-only arm did not. Both arms showed an increased rate of thromboembolic events and stroke. Both arms showed protection against fractures and with protection against colon cancer only in the E+P arm. These results have been widely generalized as indicating a negative risk/benefit ratio for HRT in menopausal women. The WHI results are at odds with results of large epidemiological studies that showed protection against cardiovascular disease. Although the latter data are, in part, confounded by a "healthy user bias," much of the inconsistency may be explained by the fact that women in the latter studies initiated HRT at the menopausal transition, whereas the WHI trial was conducted in older women (mean age 63.3), who were, on average, approx 12 yr postmenopausal. In addition, older trials included women on either unopposed estrogen therapy (ERT) or cyclic HRT regimens. Whatever other forces may have been at work, observational and experimental evidence supports the conclusion that estrogen's atheropreventive effects predominate early, in the absence of vulnerable plaque to be ruptured or thrombotic episodes propagated by narrowed lumens and intravascular turbulence. On the contrary, age-related adverse effects of HRT may prevail once complex atheromas and luminal narrowing/irregularity are established. It is known that prevalence of subclinical "at-risk" atherosclerotic lesions increases in women during the first 5-10 yr after menopause. Furthermore, animal and clinical evidence supports the use of lower doses of estrogen than were employed in the WHI in older/longer postmenopausal women.

Hormone replacement therapy, C-reactive protein, and fibrinogen in healthy postmenopausal women

OBJECTIVE

To investigate short-term and long-term effects of combined hormone replacement therapy (HRT) on C-reactive protein (CRP) and fibrinogen plasma concentrations in healthy postmenopausal women.

METHODS

In this cross-sectional study 241 healthy postmenopausal women were enrolled. A total of 81 women were receiving the following treatments for 3 months; transdermal 17beta-estradiol (17beta-E2) + medroxyprogesterone acetate (MPA) (n = 21), oral 17beta-E2 + norethisterone acetate (NETA) (n = 27), and conjugated equine estrogens (CEE) + MPA (n = 33). The same combined therapies were implemented in another 58 women for 12 months; transdermal 17beta-E2 + MPA (n = 10), oral 17beta-E2 + NETA (n = 16), and CEE + MPA (n = 32). Control group included 102 healthy postmenopausal women not receiving HRT. The effect of the type and the duration of HRT regimens on plasma levels of CRP, fibrinogen and lipids were investigated.

RESULTS

Median CRP concentrations were significantly higher in women receiving oral 17beta-E2 + NETA (P = 0.037) and CEE + MPA (P = 0.0001) for 3 months than in women taking the same types of HRT for 12 months and of those were not on HRT. Median CRP levels were similar in women taking transdermal 17beta-E2 + MPA for 3 and 12 months, compared with controls. Fibrinogen levels were not different between nonusers and any group of HRT users.

CONCLUSIONS

These elevated levels of CRP, which appears very recently as a crucial marker for cardiovascular disease, may be responsible for the early increased cardiovascular risk after starting oral combined HRT. But this increased risk in the early period seems to decrease with long-term use. Transdermal 17beta-E2 + MPA had insignificant effect on CRP both in short-term or in long-term use.

The prevention of breast cancer

BACKGROUND

Despite advances in the early detection and treatment of breast carcinoma, the mortality and morbidity rates associated with this disease remain high. Primary prevention, therefore, offers the best chance of making a major impact on outcome.

METHODS

The aim was to review the rationale, current stage of development and adverse effects of the strategies involved in the primary prevention of breast carcinoma. A review of the literature was undertaken by searching the MEDLINE database for the period 1966-2002 without language restrictions.

RESULTS AND CONCLUSION

Currently, the only agent to have general approval for chemoprevention of breast carcinoma is tamoxifen. Women who derive the greatest benefit in terms of risk reduction from tamoxifen are premenopausal with a 5-year Gail risk factor of more than 1.66 per cent, postmenopausal with a 5-year Gail risk factor of more than 3 per cent, and postmenopausal without a uterus. In these specific subgroups, tamoxifen should be considered for the chemoprevention of breast carcinoma. Raloxifene, retinoids, aromatase inhibitors and cyclo-oxygenase 2 inhibitors require further clinical investigation before adoption in this context. Surgical intervention should largely be limited to those women who have a BRCA1 or BRCA2 mutation.

Current use of unopposed estrogen and estrogen plus progestin and the risk of acute myocardial infarction among women with diabetes: the Northern California Kaiser Permanente Diabetes Registry, 1995-1998

BACKGROUND

Little is known about hormone replacement therapy (HRT) and risk for myocardial infarction (MI) in diabetic women. We examined associations of current HRT, estrogen dosage, and time since HRT initiation with risk of acute MI in diabetic women.

METHODS AND RESULTS

Cox proportional hazards models, with current HRT modeled as a time-dependent covariate, were used to assess the 3-year risk of MI. Among 24 420 women without a recent MI (mean age 64.9 years), 1110 incident MIs were identified. After adjustment for cardiovascular risk factors, current HRT was associated with reduced MI risk (relative hazard [RH] 0.84, 95% CI 0.72 to 0.98). The RH for MI associated with current estrogen plus progestin use was 0.77 (95% CI 0.61 to 0.97), and the RH for MI associated with current unopposed estrogen use was 0.88 (95% CI 0.73 to 1.05). Women were at reduced MI risk if they were taking a low or medium dose of estrogen (equivalent to <0.625 or 0.625 mg of conjugated estrogen, respectively) but not a high dose (>0.625 mg of conjugated estrogen or its equivalent). Among those whose current use of HRT was <1 year, the RH for MI was 1.03 (95% CI 0.74 to 1.44), whereas among users for > or =1 year, the RH was 0.81 (95% CI 0.66 to 1.00). Among 580 women with a recent MI (mean age 69.2 years), 89 recurrent MIs were identified. An increased risk of recurrent MI was observed among current HRT users (RH 1.78, 95% CI 1.06 to 2.98), which was higher among those with current use for <1 year (RH 3.84, 95% CI 1.60 to 9.20).

CONCLUSIONS

In women without a recent MI, use of estrogen plus progestin was associated with decreased risk of MI. However, HRT was associated with increased risk of MI in women with history of a recent MI. Data from clinical trials in diabetic women are needed.

Mechanism of raloxifene-induced relaxation in femoral veins depends on ovarian hormonal status

Experiments were designed to study effects of raloxifene, a selective estrogen receptor modulator, on venous endothelium and smooth muscle. Rings of femoral veins with and without endothelium from adult gonadally intact, and ovariectomized female pigs were suspended for measurement of isometric force in organ chambers. Concentration-response curves to raloxifene (10-9-10-5 M) were obtained in rings at baseline tension or following contraction with prostaglandin (2 x 10-6 M) in the absence or presence of NG-monomethyl-l-arginine (l-NMMA) (nitric oxide synthase inhibitor), 1H-(1.2.4) oxadiazolo (4,3-A) quinoxalin-1-one (ODQ, soluble guanylate cyclase inhibitor), tetraethylammonium acetate (TEA; potassium channel blocker), or indomethacin (cyclooxygenase inhibitor). Raloxifene caused acute, concentration-dependent relaxations that were greater in rings with than in rings without endothelium from both groups. The l-NMMA significantly inhibited relaxations to raloxifene in rings with endothelium from ovariectomized females whereas TEA only inhibited relaxations in rings with endothelium from intact female pigs. ODQ and indomethacin significantly inhibited relaxations in rings with endothelium from both groups. These results suggest that raloxifene acutely relaxes femoral veins through release of endothelium-derived factors and by direct stimulation of vascular smooth muscle cells. Whether nitric oxide or potassium channel activation contributes to relaxations by raloxifene may depend on ovarian hormonal status of the animal.

Postexercise alpha-adrenergic receptor hyporesponsiveness in hypertensive rats is due to nitric oxide

We tested the hypothesis that a single bout of dynamic exercise produces a postexercise hypotension (PEH) and alpha(1)-adrenergic receptor hyporesponsiveness in spontaneously hypertensive rats (SHR). The postexercise alpha(1)-adrenergic receptor hyporesponsiveness is due to an enhanced buffering of vasoconstriction by nitric oxide. Male (n = 8) and female (n = 5) SHR were instrumented with a Doppler ultrasonic flow probe around the femoral artery. Distal to the flow probe, a microrenathane catheter was inserted into a branch of the femoral artery for the infusion of the alpha(1)-adrenergic receptor agonist phenylephrine (PE). A microrenathane catheter was inserted into the descending aorta via the left common carotid artery for measurements of arterial pressure (AP) and heart rate. Dose-response curves to PE (3.8 x 10(-3) - 1.98 x 10(-2)microg/kHz) were generated before and after a single bout of dynamic exercise. Postexercise AP was reduced in male (13 +/- 3 mmHg) and female SHR (18 +/- 7 mmHg). Postexercise vasoconstrictor responses to PE were reduced in males due to an enhanced influence of nitric oxide. However, in females, postexercise vasoconstrictor responses to PE were not altered. Results suggest that nitric oxide- mediated alpha(1)-adrenergic receptor hyporesponsiveness contributes to PEH in male but not female SHR.

Gender-related differences in proliferative responses of vascular smooth muscle cells to endothelin-1

Endothelin-1 is an endothelium-derived factor which alters tone and proliferation of vascular smooth muscle and has been implicated in the development of atherosclerosis. Estrogen modulates production of and contractile responses to endothelin-1. Since atherosclerosis is less in estrogen-replete women compared to men, experiments were designed to determine whether or not there were gender-associated differences in proliferative responses to endothelin-1 and effect of estrogen status on those responses. Proliferation of smooth muscle cells derived from coronary arteries of sexually mature, gondally intact male and female and oophorectomized female pigs was determined by thymidine incorporation in the absence and presence of endothelin-1 with and without 17beta-estradiol. Endothelin-1 (10(-9) M to 10(-7) M) significantly inhibited proliferation only in coronary smooth muscle cells from intact female pigs. Addition of beta-estradiol inhibited proliferation of cells from intact females but there was not a synergistic effect with endothelin-1. Gender associated inhibition of smooth muscle proliferation by endothelin-1 may contribute, in part, to cardioprotection noted in estrogen-replete states.

Antiresorptive treatment of postmenopausal osteoporosis: comparison of study designs and outcomes in large clinical trials with fracture as an endpoint

Antiresorptive treatments for postmenopausal osteoporosis have been studied extensively, but due to the volume of published data and lack of head-to-head trials, it is difficult to evaluate and compare their fracture reduction efficacy. The objective of this review is to summarize the results from clinical trials that have fracture as an endpoint and to discuss the factors in study design and populations that can affect the interpretation of the results. Although there are numerous observational studies suggesting that estrogen and hormone replacement therapies may reduce the risk of vertebral and nonvertebral fractures, there is no large, prospective, randomized, placebo-controlled, double-blind clinical trial demonstrating fracture efficacy. The effects of raloxifene, alendronate, risedronate, and salmon calcitonin on increasing bone mineral density (BMD) and decreasing fracture risk have been shown in randomized, placebo-controlled, double-blind clinical trials of postmenopausal women with osteoporosis. Although the increases in lumbar spine BMD vary greatly in these trials, the decrease in relative risk of vertebral fractures is similar among therapies. However, nonvertebral fracture efficacy has not been consistently demonstrated. Combined administration of two antiresorptive therapies results in greater BMD increases, but the effects on fracture risk are unknown. Direct comparisons of clinical trial results should be considered carefully, given the differences in study design and populations. Differences in study design that may influence the efficacy of fracture risk reduction include calcium and vitamin D supplementation, primary fracture endpoints, definition of vertebral deformity or fracture, discontinuation rates, and statistical power. Factors in the study population that may influence fracture efficacy include the age of the population and the proportion of subjects with prevalent fractures. The use of surrogate endpoints such as BMD to predict fracture risk should be approached with caution, as the relationship between BMD changes and fracture risk reduction with antiresorptive therapies is uncertain. Consideration of these results from clinical trials can contribute to clinical judgment in selecting the best treatment option for postmenopausal osteoporosis.

Hormones and the health of women: past, present, and future. Keynote address

The past and possible future roles for hormone use to prevent or encourage pregnancy and to manage or prevent menopause are considered. Beginning in the 1880s, gonadal extracts were used for 50 years to improve health and vigor; evidence for the benefit of these extracts was lacking. Oral contraceptives revolutionized women's lives in the 1960s but had side effects unsuspected until after marketing. Hormone replacement therapy, used for 50 years without large clinical trials of disease outcomes, now proves to have rather similar side effects. Physicians and politicians played interesting roles in their initial distrust and later embrace of hormones. Future uses of sex hormones are likely to be viewed as overmedicalization initially, and time will tell whether these uses are healthy or merely controversial.

Women and coronary heart disease

Coronary heart disease (CHD) is the leading cause of death in men and women in the United States. The incidence of CHD during midlife is lower in women than men, but the gap narrows with each decade. Because women have a longer life span than men, the absolute numbers of CHD deaths are roughly equal. Effective diagnosis of CHD in women requires the recognition of gender differences in presentation and pathogenesis. Women present with atypical symptoms and are less likely to have adequate primary prevention. This article discusses the differences between men and women in CHD and examines the assessment, diagnosis, and clinical management of CHD in women.

Effects of raloxifene and hormone replacement therapy on markers of serum atherogenicity in healthy postmenopausal women

OBJECTIVE

To determine the effect of raloxifene (RLX) and hormone replacement therapy (HRT) on non-high density lipoprotein cholesterol (non-HDL-C) levels and the apolipoprotein-B/apolipoprotein-A1 (apo-B/apo-A1) concentration ratio, markers of serum atherogenicity, in postmenopausal women.

METHODS

Three hundred and ninety healthy postmenopausal women aged 45-72 years were enrolled in a double-blind, randomized, placebo-controlled, parallel trial at eight outpatient sites in the United States. Women were randomly assigned to receive continuous combined HRT (0.625 mg/day conjugated equine estrogen and 2.5 mg/day medroxyprogesterone acetate), 60 or 120 mg/day raloxifene, or placebo for 6 months. Serum concentrations of non-HDL cholesterol and the apo-B/apo-A1 concentration ratio were measured in serum samples obtained at baseline and at 6 months of treatment.

RESULTS

At 6 months, non-HDL-C and apo-B/apo-A1 were significantly reduced by 60 mg/day RLX (10 and 11%, respectively), 120 mg/day RLX (9 and 12%, respectively) and HRT (10 and 12%, respectively), compared with placebo. The effect of all treatments to lower non-HDL-C and apo-B/apo-A1 was greatest in women with hypercholesterolemia (total-C>240 mg/dl) at baseline. Among women with undesirable (>160 mg/dl) non-HDL cholesterol at baseline, RLX and HRT lowered the percentage of these women remaining above this threshold after 6 months (placebo, 89%; 60 mg/day RLX, 61%; 120 mg/day RLX, 74%; HRT, 58%). Similar results were observed for women with high (>190 mg/dl) non-HDL cholesterol at baseline.

CONCLUSION

In healthy postmenopausal women, RLX and HRT lower serum non-HDL-C and apo-B/apo-A1, indicators of serum atherogenicity, to a similar extent.

Vascular effects of estrogens: arterial protection versus venous thrombotic risk

Mechanisms by which estrogen reduces the risk of arterial disease, while simultaneously increasing the risk of venous thrombosis in postmenopausal women, are not clearly understood. In addition to providing beneficial arterial effects on the lipid profile, estrogen both increases production of nitric oxide and decreases production of endothelin-1 from arterial endothelium, decreases intracellular calcium in arterial smooth muscle and might favor fibrinolysis. All of these effects could act in concert to protect against development of arterial occlusive disease. However, comparable effects on venous endothelium and smooth muscle have not been studied systematically, and although blood elements such as platelets and leukocytes contain estrogen receptors, much remains to be learned about the effect that dose and duration of estrogen-treatment might have upon these cells. An integrative approach to understanding the actions of estrogen on the venous system and the interaction of blood elements with the vascular wall is necessary before new therapeutic interventions will provide arterial protection with no risk of venous thrombosis.

Indicators of lifetime estrogen exposure: effect on breast cancer incidence and interaction with raloxifene therapy in the multiple outcomes of raloxifene evaluation study participants

PURPOSE

To test the hypothesis that risk factors related to lifetime estrogen exposure predict breast cancer incidence and to test if any subgroups experience enhanced benefit from raloxifene.

PATIENTS AND METHODS

Postmenopausal women with osteoporosis (N = 7,705), enrolled onto the Multiple Outcomes of Raloxifene Evaluation (MORE) trial, were randomly assigned to receive placebo, raloxifene 60 mg/d, or raloxifene 120 mg/d for 4 years. Breast cancer risk was analyzed by the following baseline characteristics indicative of estrogen exposure: previous hormone replacement therapy, prevalent vertebral fractures, family history of breast cancer, estradiol level, bone mineral density (BMD), body mass index, and age at menopause. Therapy-by-subgroup interactions were assessed using a logistic regression model.

RESULTS

Overall, women with the highest one-third estradiol levels (> or = 12 pmol/L) had a 2.07-fold increased invasive breast cancer risk compared with women with lower levels. Raloxifene significantly reduced breast cancer risk in both the low- and high-estrogen subgroups for all risk factors examined (P <.05 for each comparison). The women with the highest BMD and those with a family history of breast cancer experienced a significantly greater therapy benefit with raloxifene, compared with the two thirds of patients with lower BMD or those without a family history, respectively; the subgroup-by-therapy interactions were significant (P =.005 and P =.015, respectively).

CONCLUSION

The MORE trial confirms that increased lifetime estrogen exposure increases breast cancer risk. Raloxifene therapy reduces breast cancer risk in postmenopausal osteoporotic women regardless of lifetime estrogen exposure, but the reduction is greater in those with higher lifetime exposure to estrogen.

Midlife women making hormone therapy decisions

This study focuses on midlife women aged 40-65 years who were in transition to menopause, were menopausal or had a hysterectomy, to examine and better understand hormone therapy (HT) choices women make. Among the nationally representative sample of women in the Commonwealth Fund 1998 Survey of Women's Health (n = 884), 39% of the menopausal women reported current HT use. The two primary reasons for initiating HT are following a doctor's recommendation and seeking relief of menopausal symptoms. Age, education, race, hysterectomy status, having health insurance, use of calcium supplements and comfort in communicating with a doctor are important factors associated with HT use. This study underscores the importance of physicians and other health professionals providing accurate HT information to assist women in making HT decisions.

Raloxifene: A selective estrogen receptor modulator (SERM) with multiple target system effects

Selective estrogen receptor modulators (SERMs) exhibit a pharmacologic profile characterized by estrogen agonist activity in some tissues with estrogen antagonist activity in other tissues. These compounds were initially called "antiestrogens," but it was subsequently recognized that this inadequately described their spectrum of activities. The first widely used SERM, tamoxifen, has estrogen antagonist activity in breast tissue but shows estrogen-like activity in other tissues. Raloxifene is another SERM in clinical use, and it was developed to avoid some of the undesirable estrogen agonist actions of other SERMs to improve the drug safety profile. Raloxifene has been introduced for clinical use in treatment and prevention of postmenopausal osteoporosis. This review will explore the preclinical and clinical pharmacology of raloxifene, and compare it to other SERMs currently available for clinical use.

The role of selective estrogen receptor modulators in the prevention and treatment of osteoporosis

Osteoporosis can affect almost everyone in the population, and although clinical outcome of fracture is manifested in late life, the disease process begins in the early postmenopausal years in women. The pharmacologic agents currently available for osteoporosis prevention and treatment act by inhibiting bone resorption, and include estrogen or hormone replacement therapy (estrogen with progestin), bisphosphonates, salmon calcitonin nasal spray, and selective estrogen receptor modulators (SERMs). Raloxifene is a benzothiophene SERM that has estrogen against effects in bone and on serum lipid metabolism and estrogen antagonist effects on breast and uterine tissue. This article summarizes the effects of these antiresorptive agents, as measured by changes in bone mineral density, biochemical markers of bone turnover, and incident fractures in postmenopausal osteoporosis.

Continued breast cancer risk reduction in postmenopausal women treated with raloxifene: 4-year results from the MORE trial. Multiple outcomes of raloxifene evaluation

Raloxifene, a selective estrogen receptor modulator approved for the prevention and treatment of postmenopausal osteoporosis, has shown a significant reduction in breast cancer incidence after 3 years in this placebo-controlled, randomized clinical trial in postmenopausal women with osteoporosis. This article includes results from an additional annual mammogram at 4 years and represents 3,004 additional patient-years of follow-up in this trial. Breast cancers were ascertained through annual screening mammograms and adjudicated by an independent oncology review board. A total of 7,705 women were enrolled in the 4-year trial; 2,576 received placebo, 2,557 raloxifene 60 mg/day, and 2,572 raloxifene 120 mg/day. Women were a mean of 66.5-years old at trial entry, 19 years postmenopause, and osteoporotic (low bone mineral density and/or prevalent vertebral fractures). As of 1 November 1999, 61 invasive breast cancers had been reported and were confirmed by the adjudication board, resulting in a 72% risk reduction with raloxifene (relative risk (RR) 0.28, 95% confidence interval (CI) 0.17, 0.46). These data indicate that 93 osteoporotic women would need to be treated with raloxifene for 4 years to prevent one case of invasive breast cancer. Raloxifene reduced the risk of estrogen receptor-positive invasive breast cancer by 84% (RR 0.16, 95% CI 0.09, 0.30). Raloxifene was generally safe and well-tolerated, however, thromboembolic disease occurred more frequently with raloxifene compared with placebo (p=0.003). We conclude that raloxifene continues to reduce the risk of breast cancer in women with osteoporosis after 4 years of treatment, through prevention of new cancers or suppression of subclinical tumors, or both. Additional randomized clinical trials continue to evaluate this effect in postmenopausal women with osteoporosis, at risk for cardiovascular disease, and at high risk for breast cancer.

Interaction of gender and exercise training: vasomotor reactivity of porcine skeletal muscle arteries

The purpose of the present study was to test the hypothesis that gender influences exercise training-induced adaptations of vascular reactivity of porcine arteries that provide blood flow to skeletal muscle and femoral and brachial arteries. Male and female Yucatan miniature swine were exercise trained on a motor-driven treadmill or cage confined for 16-20 wk. Contractile responses of arterial rings were evaluated in vitro by determining concentration-response curves for endothelin-1 (ET-1; 10(-10) to 10(-7) M) and norepinephrine (NE; 10(-10) to 10(-4) M). Relaxation responses of arteries precontracted with 30 microM PGF(2alpha) were examined for endothelium-dependent agents [bradykinin (BK; 10(-11) to 10(-6) M), ACh (10(-10) to 10(-4) M), and a Ca(2+) ionophore, A-23187 (10(-6) M)] and a endothelium-independent agent [sodium nitroprusside (10(-10) to 10(-4) M)]. Arteries from female pigs developed greater contractile force in response to ET-1 than arteries from male pigs, whereas contractile responses to NE and KCl were similar in arteries from both genders. Femoral arteries from females exhibited greater endothelium-mediated vasorelaxation (BK and ACh) than did those from males. In contrast, brachial arteries of males were more responsive to BK and ACh than brachial arteries of females. Exercise training increased ET-1-induced contractions in arteries from males (without endothelium) but not in arteries from females. Training had no effect on endothelium-dependent relaxation in arteries from males but increased relaxation responses in brachial arteries from females. We conclude that both gender and anatomic origin of the artery influence exercise training-induced adaptations of vascular reactivity of porcine skeletal muscle conduit arteries.

Prevention of coronary artery disease

The magnitude of cardiovascular disease is enormous. When the risk factors that predispose a patient to heart disease are recognized early and the appropriate intervention is instituted, the incidence of morbidity and mortality from coronary heart disease can be reduced. Lifestyle modification and the judicious use of medications can improve the complications of heart disease and prevent its onset.

Estrogen receptor transcription and transactivation: Estrogen receptor knockout mice: what their phenotypes reveal about mechanisms of estrogen action

Natural, synthetic and environmental estrogens have numerous effects on the development and physiology of mammals. Estrogen is primarily known for its role in the development and functioning of the female reproductive system. However, roles for estrogen in male fertility, bone, the circulatory system and immune system have been established by clinical observations regarding sex differences in pathologies, as well as observations following menopause or castration. The primary mechanism of estrogen action is via binding and modulation of activity of the estrogen receptors (ERs), which are ligand-dependent nuclear transcription factors. ERs are found in highest levels in female tissues critical to reproduction, including the ovaries, uterus, cervix, mammary glands and pituitary gland. Since other affected tissues have extremely low levels of ER, indirect effects of estrogen, for example induction of pituitary hormones that affect the bone, have been proposed. The development of transgenic mouse models that lack either estrogen or ER have proven to be valuable tools in defining the mechanisms by which estrogen exerts its effects in various systems. The aim of this article is to review the mouse models with disrupted estrogen signaling and describe the associated phenotypes.

Hormonal and Nonhormonal Therapies for the Postmenopausal Woman: What is the Evidence for Cardioprotection?

Despite biologically plausible mechanisms whereby estrogen may confer cardioprotection as well as observational data suggesting cardiovascular benefit, data from the sole randomized controlled clinical outcomes trial reported on the benefit of hormone use. A trend was observed in the Heart and Estrogen/progestin Replacement Study (HERS) of an early increase in coronary events with possible late benefit, and in a recent angiographic trial, the Estrogen Replacement and Atherosclerosis trial (ERA) where no benefit was seen. Furthermore, selective estrogen receptor modulators may enable dissociation of estrogen risks and benefits; the selective estrogen replacement modulator raloxifene is under study in a large randomized clinical outcomes trial entitled the Raloxifene Use for the Heart trial (RUTH). (c) 2000 by CVRR, Inc.

Prescribing hormone replacement therapy for menopausal symptoms

This paper addresses the clinical presentation of menopause, pretreatment assessment for hormone replacement therapy, benefits and risks of this treatment, common hormone replacement regimens and their side effects, and patient management. The case-based discussion focuses on the clinical management of a patient who is considering hormone replacement therapy for menopausal symptoms.

Hormone replacement therapy

Hormone replacement therapy is increasingly being used for purposes unrelated to the alleviation of menopausal symptoms, such as the prevention of osteoporosis and cardiovascular disease. Clinical trials, however, suggest that the one drug/many purposes concept may be too optimistic. The availability of new estrogen-like compounds and the discovery of a second estrogen receptor have opened new possibilities for more specific drug development.

Postmenopausal hormone use for cardioprotection: what we know and what we must learn

Coronary heart disease is a highly prevalent and lethal illness for women, particularly in their menopausal years, a fact that fostered interest in hormone use for cardioprotection. Despite the compelling evidence of cardiovascular benefit of estrogen therapy and estrogen and progestin therapy in observational studies of postmenopausal women, and multiple biologically plausible mechanisms for estrogen benefit, precise clinical outcome information from prospective randomized controlled trials is lacking. The only such trial reported, the Heart and Estrogen/Progestin Replacement Study, not only failed to demonstrate cardioprotection, but showed an early adverse outcome in women with documented coronary heart disease who received daily conjugated equine estrogen and medroxy-progesterone acetate. Several large randomized clinical trials of hormone and selective estrogen receptor moderator therapy for primary and secondary prevention are currently underway.

American Society of Clinical Oncology technology assessment on breast cancer risk reduction strategies: tamoxifen and raloxifene

OBJECTIVE

To conduct an evidence-based technology assessment to determine whether tamoxifen and raloxifene as breast cancer risk-reduction strategies are appropriate for broad-based conventional use in clinical practice.

POTENTIAL INTERVENTION

Tamoxifen and raloxifene.

OUTCOME

Outcomes of interest include breast cancer incidence, breast cancer-specific survival, overall survival, and net health benefits.

EVIDENCE

A comprehensive, formal literature review was conducted for tamoxifen and raloxifene on the following topics: breast cancer risk reduction; tamoxifen side effects and toxicity, including endometrial cancer risk; tamoxifen influences on nonmalignant diseases, including coronary heart disease and osteoporosis; and decision making by women at risk for breast cancer. Testimony was collected from invited experts and interested parties.

VALUES

More weight was given to publications that described randomized trials. BENEFITS/HARMS/COSTS: The American Society of Clinical Oncology (ASCO) Working Group acknowledges that a woman's decision regarding breast cancer risk-reduction strategies will depend on the importance and weight attributed to the information provided regarding both cancer and non-cancer-related risks.

CONCLUSIONS

For women with a defined 5-year projected risk of breast cancer of >/= 1.66%, tamoxifen (at 20 mg/d for up to 5 years) may be offered to reduce their risk. It is premature to recommend raloxifene use to lower the risk of developing breast cancer outside of a clinical trial setting. On the basis of available information, use of raloxifene should currently be reserved for its approved indication to prevent bone loss in postmenopausal women. Conclusions are based on single-agent use of the drugs. At the present time, the effect of using tamoxifen or raloxifene with other medications (such as hormone replacement therapy), or using tamoxifen and raloxifene in combination or sequentially, has not been studied adequately. The continuing use of placebo-controlled trials in other risk-reduction trials highlights the current unanswered issues concerning the use of such interventions, especially when the influence on net health benefit remains to be determined. Breast cancer risk reduction is a rapidly evolving area. This technology assessment represents an ongoing process with existing plans to monitor and review data and to update recommendations in a timely matter. (See

VALIDATION

The conclusions of the Working Group were evaluated by the ASCO Health Services Research Committee and by the ASCO Board of Directors.

SPONSOR

American Society of Clinical Oncology.