Fatal myocardial infarction in the Scottish adjuvant tamoxifen trial. The Scottish Breast Cancer Committee

Hormone replacement therapy, selective estrogen receptor modulators, and tissue-specific compounds: cardiovascular effects and clinical implications

In industrialized countries, coronary heart disease (CHD) is not only the leading cause of death in women but of disability as well. Menopause, regardless of age at onset, is associated with a marked increase in CHD risk. Based on epidemiologic studies demonstrating mainly positive biologic effects of hormone replacement therapy (HRT) on CHD risk factors and outcomes, earlier recommendations decreed that most, if not all, postmenopausal women should be treated with long-term HRT. Recent randomized controlled trials with clinical CHD endpoints have shown that previously held dicta may not be accurate. Selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene are alternatives to HRT. SERMs represent a growing class of compounds that act as either estrogen receptor agonists or antagonists in a tissue-selective manner. This pharmacologic profile may offer the opportunity to dissociate favorable cardiovascular effects of estrogen from unfavorable stimulatory effects on the breast and endometrium. The only data available regarding the effects of tamoxifen on cardiovascular events in postmenopausal women are from breast cancer trials. They showed fewer fatal myocardial events in women randomly assigned to tamoxifen compared with women assigned to placebo. Raloxifene is a so-called second-generation SERM. It seems clear that raloxifene increases bone mineral density, has no effect on the endometrium, and holds high promise for the prevention of breast cancer. The effect of raloxifene on cardiovascular disease is uncertain. On the basis of the Multiple Outcomes of Raloxifene Evaluation (MORE) trial, raloxifene may offer some protection to women with cardiovascular disease or to those who are at high risk. Proof that raloxifene reduces the risk of CHD requires a clinical trial with hard clinical endpoints. Such a study is currently underway. Clinical trials have demonstrated that the synthetic 19-nortestosterone derivative tibolone reduces climacteric complaints and prevent osteoporosis without causing menstrual bleeding. Tibolone lowers lipoprotein(a), fibrinogen, and plasminogen activator inhibitor-1 levels and improves glucose tolerance, insulin sensitivity, and endothelial function; however, it also lowers high-density lipoprotein cholesterol by >20%. The long-term impact of tibolone on the risk of CHD is not known and needs to be studied.

Effects of toremifene (TOR) and tamoxifen (TAM) on serum lipids in postmenopausal patients with breast cancer

This study clarified the difference in the effects on serum lipids between toremifene (TOR) and tamoxifen (TAM). To remove influencing factors, we investigated adjuvant therapy for hormone receptor-positive patients with breast cancer without lymph node metastasis. The subjects were 65 patients who were enrolled in a multicenter randomized comparative study between April 1997 and March 2001. As adjuvant therapy, 20 mg of TAM or 40 mg of TOR was administered for 1 year. The levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-1 (Apo A-1), apolipoprotein A(Apo B), and lipoprotein a (Lp(a)) were measured prior to administration and 3, 6, and 12 months after the start of administration. TC, LDL-C, Lp(a) and Apo B significantly decreased from the third month of administration compared with values before the start of administration in both the TOR and TAM groups. HDL-C significantly increased from the third month only in the TOR group. TG significantly increased in the TAM group but significantly decreased in the TOR group in the 12th month of administration. When these two groups were compared, HDL-C was significantly higher (p < 0.01) and TG was significantly lower (p < 0.01) in the TOR group in the 12th month. Improvement of abnormal values of TG, HDL-C and LDL-C was better in the TOR group than in the TAM group after administration for 12 months. The effect on lipid metabolism showed different profiles between the two selective estrogen receptor modulators (SERMs), and TOR gave better results than TAM.

Repercussions of raloxifen, tamoxifen and estrogen on aortic atherosclerotic lesions of female rabbits submitted to ovariectomy and hypercholesterol diet

BACKGROUND

The role of hormone-replacement therapy in decreasing the risk of cardiovascular disease in women has not been firmly established. Recent studies have shown that the selective estrogen receptor modulators raloxifene, and tamoxifene, posses hypolipidemic and antiatherogenic properties.

METHODS AND RESULTS

Forty-three adult female rabbits were submitted to ovariectomy (moment 1). Three weeks after surgical recovery, they were grouped in five groups as follows (moment 2): control group (9)--normal diet; cholesterol group (8)--0.5% cholesterol added to diet; raloxifen group (8); tamoxifen group (9); estrogen group (9)--diet added by 0.5% cholesterol and 60 mg raloxifen, 20 mg tamoxifen or 0.625 mg equine conjugated estrogen. The animals from all groups were sacrificed after 13 weeks (moment 3) and the thoracic and abdominal aortas were studied. We collected digital images of the observed atherosclerotic lesions in the vessel lumen by means of a computerized method. We analyzed serum levels of total cholesterol and fractions (HDL, VLDL, and LDL), as well as triglycerides. Among the animals that received hyper cholesterol diet and medication, we noticed a reduction of the total area of atherosclerotic plaques in the tamoxifen (P < 0.05) or estrogen group (P < 0.05) compared to the cholesterol group. Serum levels of total, LDL- and HDL-cholesterol were higher for the raloxifen, tamoxifen, estrogen, and cholesterol (P = 0.0001).

CONCLUSION

Female rabbits treated with a high cholesterol diet associated to tamoxifen or estrogen had a statistically significant reduction in aortic atherosclerotic plaques. Even though there was a significant increase in cholesterol levels, we did not find any correlation between cholesterol levels and degree of aortic atherosclerotic lesion.

Plasma leptin concentration in tamoxifen-treated ovariectomized rats

Leptin, the ob gene product, has an important role in the regulation of body weight. Although tamoxifen, a nonsteroidal antiestrogenic agent, is known to have estrogenic effects on fat metabolism, its influence on adipose tissue remains unknown. In the present study, the effect of tamoxifen on the concentration of leptin was investigated in ovariectomized rats treated with tamoxifen or vehicle. The dosage of tamoxifen was extrapolated from the human dosage. Food intake, adipose tissue weight, and plasma insulin were assessed at the end of the experiment.

RESULTS

Tamoxifen-treated rats showed a significant reduction of body weight gain, food intake, adipose tissue weight and leptin concentration (p < 0.001). The plasma insulin level was significantly higher after tamoxifen treatment (p = 0.01) in tamoxifen-treated rats than in control rats. We concluded that tamoxifen reduces food intake in the acute phase and a reduction of adipose tissue gain may result in reduced levels of plasma leptin in ovariectomized rats. Furthermore, rats treated with tamoxifen may be resistant to insulin action.

Hormone Therapy and Selective Estrogen Receptor Modulators for Prevention of Coronary Heart Disease in Postmenopausal Women

Coronary heart disease is the leading cause of morbidity and mortality in women older than the age of 50 in the United States today. Traditional cardiovascular risk factors (hyperlipidemia, glucose intolerance, and hypertension) are more clearly associated with significant cardiovascular risk after menopause. The increased incidence of cardiovascular events in postmenopausal women and the evidence that cardiovascular disease on average manifests a decade later in women compared with men suggests that estrogen deficiency may predispose women to a higher cardiovascular risk. Numerous biologic mechanisms have been proposed that relate use of hormone therapy (HT) to improved lipid profiles, insulin sensitivity, and vascular reactivity. Early observational trials in the last 2 decades showed a significant decrease in cardiovascular events. Recently published randomized clinical trial results, however, have led to uncertainty about the earlier established cardiovascular benefits of HT. To complicate issues further, alternative estrogenlike compounds, selective estrogen receptor modulators, are being introduced that appear to convey similar cardiovascular benefit and notably less cancer risk than HT. The newly released randomized trials on hormone and nonhormonal agents are reviewed.

Bone mineral density among premenopausal women with early breast cancer in a randomized trial of adjuvant endocrine therapy

PURPOSE

To examine the effects on bone mineral density of 2 years of treatment with a luteinizing hormone-releasing hormone (LHRH) agonist alone or in combination with tamoxifen or tamoxifen alone in premenopausal breast cancer.

PATIENTS AND METHODS

We recruited 89 women from two centers in Stockholm participating in a randomized multicenter trial of three different endocrine approaches in the adjuvant setting (Zoladex in Premenopausal Patients Trial). The women were assigned to receive the LHRH agonist goserelin with or without tamoxifen, tamoxifen alone, or no endocrine therapy. The treatment was given for 2 years. We measured total-body bone density before start of treatment and at 12, 24, and 36 months.

RESULTS

After 2 years of treatment, there was a significant loss of bone mineral density (mean change, -5%; P <.001) in the women receiving goserelin alone. The combined goserelin and tamoxifen treatment, as well as tamoxifen alone, resulted in a lesser but statistically significant decline in bone mineral density (mean change, -1.4%; P =.02; and -1.5%; P <.001). One year after cessation of treatment, the goserelin group alone showed a partial recovery from bone loss (mean change, 1.5%; P =.02).

CONCLUSION

Two years of ovarian ablation from goserelin treatment caused a significant reduction in bone mineral density but there was a partial recovery from the bone loss 1 year after cessation of treatment. The addition of tamoxifen seems to partially counteract the demineralizing effects of goserelin.

Tamoxifen treatment reverses the adverse effects of chemotherapy-induced ovarian failure on serum lipids

In all, 146 premenopausal women with early stage breast cancer were treated with adjuvant chemotherapy. In addition, 5-year tamoxifen treatment was started after chemotherapy to those 112 patients with hormone-receptor-positive tumours while those with hormone-receptor-negative tumours received no further therapy. The serum lipid levels were followed in both groups. The levels of serum total and low-density lipoprotein (LDL) cholesterol increased significantly after chemotherapy only in patients who developed ovarian dysfunction. Total cholesterol increased +9.5% and LDL cholesterol +16.6% in patients who developed amenorrhoea (P<0.00001 and 0.00001, respectively). The cholesterol levels did not change in patients who preserved regular menstruation after chemotherapy. After 6 months of tamoxifen therapy, the total cholesterol decreased −9.7% and the LDL cholesterol −16.7% from levels after the chemotherapy, while the cholesterol concentrations remained at increased levels in the control group (P=0.001 and P<0.0001, respectively). The high-density lipoprotein cholesterol levels did not change significantly in either tamoxifen or control group. The effects of tamoxifen treatment on serum lipids after chemotherapy have not been studied before. Our current study suggests that adjuvant tamoxifen therapy reverses the adverse effects of chemotherapy-induced ovarian failure on total and LDL cholesterol and even lowers their serum levels below the baseline.

Tamoxifen improves endothelial function and reduces carotid intima-media thickness in postmenopausal women

BACKGROUND

Tamoxifen is a selective estrogen-receptor modulator shown to improve several cardiovascular risk factors in postmenopausal women with breast cancer. In animal studies tamoxifen inhibits the progression of atherosclerosis. Although the presence of a history with tamoxifen treatment is related to a lower intima-media thickness (IMT) of the common carotid artery, data from controlled follow-up studies are lacking to support this observation.

METHODS

We examined 14 postmenopausal women with early stage breast cancer with indication for tamoxifen treatment (20 mg/d) and 13 healthy postmenopausal women. Flow-mediated dilatation (FMD) of the brachial artery, combined carotid IMT, and aortic pulse wave were measured before and 6 months after treatment in the tamoxifen group and at the same times in the control group.

RESULTS

FMD and IMT were significantly increased and decreased, respectively, in the treatment group compared to the control group (FMD: +2.2% +/- 0.9% vs +0.085% +/- 1%, P =.012; IMT: -0.088 +/- 0.03 mm vs +0.04 +/- 0.03 mm, P =.018, mean +/- standard error of the mean, treatment vs control group). These differences remained significant even when adjusted for age, duration of menopause, and cardiovascular risk factors. Low-density lipoprotein cholesterol was also significantly reduced after tamoxifen treatment.

CONCLUSIONS

Tamoxifen treatment slows the progression of atherosclerosis in postmenopausal women with breast cancer as assessed by changes in carotid IMT. An improvement in endothelial function and blood lipid profile may be the reason for this beneficial effect.

A New Series of Estrogen Receptor Modulators: Effect of Alkyl Substituents on Receptor-Binding Affinity

New types of selective estrogen receptor modulators (SERMs) were synthesized and evaluated for their binding affinity and biological effect on reproductive cells. A proposed lead structure (B) was derivatized to provide compounds 30 and 44, which showed good estrogen-receptor binding affinity (K(i) values: 6.3 and 10 nM, respectively), as well as minimal impact on mammary and uterine carcinoma cells. Introduction of an alkyl group in the core structure considerably enhanced receptor-binding affinity of the compounds tested. Synthesis and structure-activity relationships of these compounds are described.

The best use of adjuvant endocrine treatments

Endocrine therapy remains important in the adjuvant treatment of pre- and postmenopausal women. Adjuvant ovarian ablation with or without tamoxifen produces effects which are equivalent to those of CMF (cyclophosphamide, methotrexate and 5-fluorouracil) chemotherapy in premenopausal women with oestrogen receptor (ER) and/or progesterone receptor (PgR) positive breast cancer. Tamoxifen alone is also effective in these women. Concurrent use of tamoxifen and ovarian ablation may be even more effective, but more studies are needed. Tamoxifen remains a standard adjuvant therapy for postmenopausal women with ER and/or PgR positive tumours. Current information supports the use of 5 years of tamoxifen but additional studies comparing 5 years to longer duration are ongoing. The aromatase inhibitor (AI) anastrozole has now been demonstrated to be better than tamoxifen in preventing recurrence in early reports from the Arimidex vs Tamoxifen And the Combination (ATAC) Trial. Ongoing trials of this and other AIs before, after, concurrent with, or substituted for tamoxifen in the adjuvant setting may soon revolutionize our approach for postmenopausal women. Adjuvant bisphosphonates have been shown to reduce the incidence of bone metastases and improve survival in two of three published adjuvant trials and are being further studied. Her-2 neu status is being explored as a predictive factor for selection of endocrine therapy, but is not yet considered standard for this purpose.

Tamoxifen Is a Potent Inhibitor of Cholesterol Esterification and Prevents the Formation of Foam Cells

Tamoxifen is a selective estrogen receptor modulator (SERM) used for the treatment and prevention of breast cancer. Tamoxifen has been reported to protect against the progression of coronary artery diseases in human and different atherosclerosis animal models by blocking the appearance of the atheromatous plaque. However, the molecular mechanism of this effect remains unknown. Acyl-CoA:cholesterol acyl transferase (ACAT) catalyzes the biosynthesis of cholesteryl esters, which are the major lipids found in the atheromatous plaque. In this paper we have tested whether ACAT might be inhibited by tamoxifen. We show, using molecular modeling, that tamoxifen displays three-dimensional structural homology with Sah 58-035 (3-[decyldimethylsilyl]-N-[2-(4-methylphenyl)-1-phenylethyl]-propanamide), a prototypical inhibitor of ACAT. We report that tamoxifen inhibits ACAT in a concentration-dependent manner on rat liver microsomal extract. We show that the presence on estrogen receptor ligands of a backbone isosteric to the diphenyl ethane backbone of Sah 58-035 constitutes a pharmacophore for ACAT inhibition. More importantly, tamoxifen was able to inhibit ACAT on intact macrophages stimulated with acetylated low-density lipoproteins and blocked the formation of foam cells, a step that precedes the formation of the atheromatous plaque. This work constitutes the first evidence that tamoxifen is an inhibitor of ACAT and foam cell formation at therapeutic doses and that this may account for its atheroprotective action.

Hyper-reactivity of cerebral arteries from ovariectomized rats: therapeutic benefit of tamoxifen

1. An increased incidence of systemic hypertension has been documented in postmenopausal women and identified as an independent risk factor in the development of cerebrovascular stroke. The present study examined whether cerebrovascular reactivity was increased in the hypertensive ovariectomized rat, and explored the potential therapeutic benefit of the partial estrogen receptor agonist tamoxifen. 2. Female Sprague-Dawley rats were subjected to bilateral ovariectomy (OVX, n=16) or a sham operation (n=8). At 6-week postsurgery, rats were anesthetized to assess ventricular contractility and blood pressure. In a second series of experiments, OVX rats (n=8) were given tamoxifen starting 3 weeks postsurgery, and continued for 3 weeks. At the end of each protocol, the middle cerebral artery was harvested and rings were mounted in wire-myographs to measure isometric tension. 3. Systolic arterial pressure (SAP) was significantly increased (P<0.05) in the OVX rat (174+/-8 mmHg), as compared to sham (135+/-6 mmHg). The resting tension of isolated cerebral arteries from OVX rats (186+/-15 mg) was significantly elevated (P<0.05), as compared to sham (129+/-9 mg). Phenylephrine treatment did not elicit a constriction of cerebral arteries isolated from sham rats, whereas a potent response (P<0.05) was observed in OVX rats. Nitric oxide (NO) synthase inhibition with L-NNA led to a limited contraction in sham rats (8+/-3% of Emax), whereas a significant (P<0.05) increase was observed in OVX rats (34+/-12% of Emax). Lastly, vascular sensitivity (pD2) to sodium nitroprusside was significantly increased (P<0.05) in OVX rats, as compared to sham. 4. Tamoxifen therapy normalized the resting tension of isolated cerebral arteries from OVX rats, abrogated phenylephrine-mediated contraction, and modestly reduced SAP. By contrast, tamoxifen treatment of OVX rats did not attenuate L-NNA-mediated contractile response of cerebral arteries. 5. These data demonstrate that the cerebral artery isolated from the OVX rat was associated with an exaggerated vasoconstrictor response to phenylephrine, and altered NO-dependent vascular reactivity. The administration of tamoxifen to OVX rats normalized cerebral artery reactivity to phenylephrine. These findings provide the impetus to examine the potential therapeutic benefit of the partial estrogen receptor agonist tamoxifen to reduce the incidence of cerebrovascular stroke in postmenopausal women.

Meta-analysis of vascular and neoplastic events associated with tamoxifen

OBJECTIVE

Tamoxifen reduces the risk of developing breast cancer but also affects the risks of certain vascular and neoplastic events. Our purpose was to estimate the effects of tamoxifen on potentially life-threatening vascular and neoplastic outcomes.

DESIGN

Random effects meta-analysis of published randomized controlled trials.

PATIENTS

Participants in all trials in which a treatment arm that included tamoxifen was compared to a similar control arm. Breast cancer risk reduction and treatment trials were included.

INTERVENTIONS

Tamoxifen at variable dose and duration.

MEASUREMENTS AND MAIN RESULTS

Thirty-two trials (52,929 patients) reported one or more outcomes of interest. Tamoxifen was associated with significantly increased risks of endometrial cancer (relative risk [RR] 2.70; 95% CI, 1.94 to 3.75), gastrointestinal cancers (RR 1.31; 95% CI, 1.01 to 1.69), strokes (RR 1.49; 95% CI, 1.16 to 1.90), and pulmonary emboli (RR 1.88; 95% CI, 1.77 to 3.01). Tamoxifen had no effect on secondary malignancies other than endometrial and gastrointestinal cancers (RR 0.96; 95% CI, 0.81 to 1.13). In contrast, tamoxifen significantly decreased myocardial infarction deaths (RR 0.62; 95% CI, 0.41 to 0.93) and was associated with a statistically insignificant decrease in myocardial infarction incidence (RR 0.90; 95% CI, 0.66 to 1.23). Postmenopausal women had greater risk increases for neoplastic outcomes.

CONCLUSIONS

This meta-analysis of randomized trials found tamoxifen use to be significantly associated with several neoplastic and vascular outcomes. Consideration of tamoxifen use requires balance of potential benefits and risks.

Inhibition of cloned HERG potassium channels by the antiestrogen tamoxifen

Tamoxifen is a nonsteroidal antiestrogen that is commonly used in the treatment of breast cancer. Although antiestrogenic drugs are generally believed not to cause acquired long QT syndrome (LQTS), concerns have been raised by recent reports of QT interval prolongation associated with tamoxifen treatment. Since blockade of human ether-a-go-go-related gene (HERG) potassium channels is critical in the development of acquired LQTS, we investigated the effects of tamoxifen on cloned HERG potassium channels to determine the electrophysiological basis for the arrhythmogenic potential of this drug. HERG channels were heterologously expressed in Xenopus laevis oocytes, and currents were measured using the two-microelectrode voltage clamp technique. Tamoxifen blocked HERG potassium channels with an IC(50) value of 45.3 microM. Inhibition required channel opening and unblocking occurred very slowly. Analysis of the voltage-dependence of block revealed loss of inhibition at positive membrane potentials, indicating that strong channel inactivation prevented block by tamoxifen. No marked changes in electrophysiological parameters such as voltage-dependence of activation or inactivation, or inactivation time constant could be observed, and block was not frequency-dependent. This study demonstrates that HERG potassium channels are blocked by the antiestrogenic drug tamoxifen. We conclude that HERG current inhibition might be an explanation for the QT interval prolongation associated with this drug.

Differential regulation of proteasome-dependent estrogen receptor alpha and beta turnover in cultured human uterine artery endothelial cells

Estrogen-induced loss of estrogen receptor (ER) alpha expression limits estrogen responsiveness in many target cells. However, whether such a mechanism contributes to changes in vascular endothelial ER alpha and/or ER beta levels is unclear. Using RT-PCR assays, we did not find any regulation of ER alpha or ER beta mRNA expression in human uterine artery endothelial cell (HUAEC) nuclear extracts on stimulation with 17 beta-estradiol for 1 or 2 h. By contrast, Western analysis on HUAEC extracts revealed that 17 beta-estradiol was capable of down-regulating both ER alpha and ER beta protein starting 1 h after treatment, an effect that can be blocked by pretreatment with tamoxifen as well as with the proteasome inhibitor lactacystin. The proteolysis inhibitors insulin, cycloheximide, and puromycin impede ER alpha, but not ER beta, turnover. Ubiquitin, but not its competitive inhibitor methyl-ubiquitin, induces rapid turnover of both ERs in a cell-free system of MCF-7 and HUAEC extracts. We, thus, propose the existence of estrogen-induced ER degradation that serves to control physiological responses in an estrogen target tissue, i.e. human vascular endothelium, by down- regulating ER alpha as well as ER beta through different proteasomal uptake mechanisms.

Selective estrogen-receptor modulators

Tamoxifen is useful for adjuvant treatment of breast cancer and in some women for the prevention of breast cancer. The risk-benefit ratio in regard to the skeleton and perhaps other organ systems may very well be different for postmenopausal versus premenopausal women. In postmenopausal women, tamoxifen (20 mg/d) increased BMD in the spine and perhaps the hip; however, the effect on fracture risk is unclear. Therefore, for postmenopausal women with osteoporosis, consideration should be given to the addition of an agent that is shown to have efficacy against fractures (such as bisphosphonates), even while these women are on tamoxifen. For women at only modest or moderate risk, with bone density above the osteoporosis range (T score above -2.5) and no major fracture history, tamoxifen is probably adequate for 5 years of use. Potentially serious adverse effects include venous thromboembolism, uterine cancer, benign uterine disease, and cataracts. Raloxifene (60 mg/d) protects against vertebral fractures over 4 years in women with osteoporosis, produces small increases in bone mass of the spine, hip, and total body, and reduces bone turnover in postmenopausal women with or without osteoporosis. No significant effect has yet been demonstrated on nonvertebral fractures after 4 years of treatment. Raloxifene has the additional benefit of substantially reducing the risk of ER-positive invasive breast cancer and does not increase the risk of uterine disease. Raloxifene increases the risk of venous thromboembolic disease to the same degree as tamoxifen and estrogen. Therefore, SERMS and estrogens are generally contraindicated in women with a previous history of venous thromboembolism or those who are at significantly increased risk. Raloxifene is probably most useful in women who have osteoporosis (T score = -2.5) or who are at risk (T score less than -1.5 with clinical risk factors) in the middle menopausal period (age 55-65) or in the early menopausal period in women who have no significant hot flashes. At this stage in life, vertebral fractures are common, but hip fractures are not. Therefore, women who take raloxifene can expect a reduction in the likelihood of having a vertebral fracture, and possibly breast cancer. The lack of definitive efficacy against hip fracture is not a major deterrent to use of this agent in this age group because hip fracture risk is very low. Raloxifene might not be the treatment of choice for elderly women who are at particularly high risk of hip fracture.

Prevention of breast cancer using SERMs and aromatase inhibitors

Breast cancer is one of the most common cancers of women in the Western world. Despite modest achievements in the treatment of this disease, there is a substantial unmet medical need to reduce the occurrence of new breast cancers. In several prospective, placebo-controlled trials, the antiestrogen tamoxifen has been shown to reduce the incidence of both invasive cancer and preinvasive breast lesions. Meanwhile, numerous other selective estrogen receptor modulators (SERMs) are being developed and trials comparing tamoxifen to these agents are ongoing. The goal of these studies is not only to show superior chemopreventive efficacy of the newer SERMs, but also an improved side-effect profile. The proof-of-principle demonstrated with tamoxifen suggests that strategies inhibiting estrogen are a logical way forward in breast cancer prevention. Aromatase inhibitors, which antagonize estrogen by blocking its synthesis from androgens, offer an alternative way of preventing the effects of estrogen and its metabolites on the breast. In this paper, the available data on SERMs including tamoxifen and raloxifene in breast cancer prevention and the data pointing to the efficacy of aromatase inhibitors in this setting are outlined.

What is the cardioprotective role of hormone replacement therapy?

A very large body of literature has yielded strong biologic and mechanistic plausibility for the consistent observational findings that estrogen is cardioprotective. Recently completed randomized, controlled trials have been interpreted as challenging the doctrine that hormone replacement is cardioprotective for postmenopausal women. However, other than the Estrogen in the Prevention of Atherosclerosis Trial, none of the currently completed (and no ongoing) randomized, controlled trials have appropriately tested the hypothesis generated from observational data that estrogen replacement is cardioprotective. This mainly results from the fact that randomized, controlled trials have not tested the same pattern and type of hormone use in the same population of women observed in the epidemiologic studies. On the other hand, recently completed randomized, controlled trials provide important but limited information concerning the clinical use of a specific regimen of hormone replacement for the prevention of cardiovascular disease in a particular population of postmenopausal women. Observations made from epidemiologic studies will have to be appropriately tested in randomized, controlled trials before any real conclusions can be drawn as to whether hormone replacement is cardioprotective.

Will the experience with tamoxifen in breast cancer help define the role of antiandrogens in prostate cancer?

Breast and prostate cancers are the two predominant hormone-responsive tumours. The use of the antioestrogen tamoxifen in the treatment of breast cancer has evolved over the past 30 y from treatment for advanced breast cancer to prevention. Tamoxifen is currently the endocrine treatment of choice for advanced breast cancer and for adjuvant therapy in a broad spectrum of women whose primary tumours have functional oestrogen receptors. It has also been shown to reduce the incidence of breast cancer in high-risk women. Non-steroidal antiandrogen therapy is used in the treatment of prostate cancer, but its role is still being defined. The clinical development of tamoxifen and that of the antiandrogens are reviewed and parallels are uncovered which provide insight into contemporary and future management of hormone-responsive prostate cancer.Prostate Cancer and Prostatic Diseases (2001) 4, 72-80

Effects of ospemifene (FC-1271a) on uterine endometrium, vaginal maturation index, and hormonal status in healthy postmenopausal women

OBJECTIVE

Selective estrogen receptor modulators (SERMs) are drugs that exhibit both estrogen agonistic and antagonistic effects that are tissue-specific. Ospemifene (FC-1271a) is a novel SERM compound, which has been shown in animal models to have estrogen-like effects on bone and the cardiovascular system, while having antiestrogen-like effects in uterus and breast. In this study, we investigated the effects of ospemifene on the uterine endometrium, vaginal maturation index and hormonal status in healthy postmenopausal women.

METHODS

The study was conducted as a double-blind, placebo-controlled phase I study, where 40 healthy postmenopausal women volunteers were randomized to receive daily oral doses of ospemifene either 25, 50, 100 or 200 mg or placebo for 12 weeks. Vaginal ultrasonography and endometrial biopsy were performed and vaginal maturation index determined at baseline and at 12 weeks' visit. Serum concentrations of estradiol, luteinizing hormone, follicle stimulating hormone (FSH), sex-hormone binding globulin (SHBG), parathyroid hormone and prolactin were determined from samples taken at baseline, at 4 days and at 4, 12, and 16 weeks' visits. Climacteric symptoms were assessed using 12 visual analogue scales (VAS) at baseline and at the end of the study.

RESULTS

No clinically significant changes were seen in endometrial thickness at any dose level. Ospemifene exerted a very weak estrogenic effect on endometrial histology. On the other hand, it induced a clear estrogenic effect on vaginal epithelium. Among the endocrine parameters only FSH and SHBG showed significant dose dependent changes; FSH decreased and SHBG increased during the treatment. In general, ospemifene was well tolerated. The 25 and 50 mg doses tended to reduce climacteric symptoms, but no statistically significant differences were observed between different doses of ospemifene and placebo. The highest dose level (200 mg) induced more subjective adverse reactions, especially hot flushes, than lower doses.

CONCLUSION

Our study suggests that a safe and well tolerated dose of ospemifene for potential clinical use may be between 25 and 100 mg. Further studies are needed to substantiate the results of this Phase I pilot study.

Effects of anastrozole on lipid metabolism compared with tamoxifen in rats

BACKGROUND

Anastrozole, a new aromatase inhibitor, has been used to treat postmenopausal metastatic breast cancer, and several clinical trials of adjuvant treatment using this agent are ongoing. However, the effects of anastrozole on lipid metabolism are unknown. The aim of this study was to evaluate the effect of anastrozole on lipid metabolism, especially lipoprotein lipase (LPL) activity, compared with tamoxifen in rats.

METHODS

Ovariectomized female rats were divided into six groups: C, controls; T, tamoxifen treatment; A, anastrozole treatment; CAT, combined anastrozole/tamoxifen treatment; NAT, no treatment after tamoxifen; and AAT, anastrozole treatment after tamoxifen. The agents were orally administered for 3 weeks. Serum total cholesterol, triglycerides, and LPL activity in postheparin plasma were measured at the end of the experiment.

RESULTS

Serum cholesterol levels were significantly lower in the T and CAT groups than in controls (P < 0.001). Serum triglyceride levels were significantly higher in the T group than in the other groups (P < 0.001). LPL activity was significantly lower in T and AAT groups (P < 0.01). There was no significant difference in any parameters in group A.

CONCLUSIONS

Anastrozole does not affect lipid metabolism including LPL activity. There was little effect on lipid profiles during combination treatment or following treatment with tamoxifen. In a clinical setting, therefore, anastrozole might be safe for patients with abnormal triglyceride profiles during tamoxifen treatment.

Postmenopausal hormone replacement therapy and atherosclerosis

The role of postmenopausal hormone replacement therapy (HRT) in the prevention of cardiovascular disease (CVD) has evolved since estrogen was first proposed to be vasoprotective. The discovery of novel molecular signaling pathways involving the estrogen receptor in vascular cells and the elucidation of numerous biologic mechanisms have suggested that HRT may exert its potentially beneficial or adverse cardiovascular effects through multiple mechanisms. Estrogen has genomic, as well as rapid nongenomic, effects that alter vasodilation, coagulation, inflammation, and the vascular injury response, some of which may have potentially beneficial or adverse cardiovascular consequences. Current guidelines do not support the use of HRT in the secondary prevention of CVD, and recent results of primary prevention trials show evidence of increased early cardiovascular risk and no overall health benefit with combination estrogen-progestin treatment. The role of estrogen alone in the primary prevention of CVD awaits the results of ongoing trials. The key to the use of estrogen replacement therapy for the prevention of CVD may be to target therapy before atherosclerosis is evident, and to identify women with genetic susceptibility who may be at increased risk for an adverse outcome associated with therapy.

Anti-atherosclerotic effects of tamoxifen in cholesterol-fed ovariectomized rabbits

It has been indicated that the anti-estrogen agent, tamoxifen, developed for the treatment of breast cancer, may act on the vascular system as an estrogen agonist. However, to our knowledge few reports suggest that tamoxifen exerts anti-atherogenic actions. In the present study, we evaluated the anti-atherosclerotic effects of tamoxifen in ovariectomized cholesterol-fed rabbits. Ovariectomized rabbits were fed a 1% cholesterol diet and divided into 4 groups: control group (C, n=5); estrogen treatment (E, n=6); low-dose tamoxifen treatment (0.5 mg/kg) (LT, n=6); and high-dose tamoxifen (1.0 mg/kg) (HT, n=7). After 6 weeks, both Oil red O-positive areas on the intimal surfaces of aortae and the ratios of intimal to medial areas (I/M ratios) measured from cross-sections of aortae were significantly lower in groups E, LT and HT compared with group C. Although there were no significant differences in serum NOx (NO2 and NO3) levels among the 4 groups, NOx levels were slightly higher in groups E, LT and HT than group C. Acetylcholine (ACh) was administered to all animals, and the responses of ear arteriole diameters were compared among the 4 groups. While ear arteriole diameters were significantly decreased in group C, no significant changes were observed in groups E, LT or HT following ACh administration. Ratios of ear arteriole diameters after to before ACh administration were significantly greater in groups E, LT and HT compared to group C. These findings suggest that tamoxifen exerts anti-atherosclerotic effects, and that these effects are attributed to the maintenance of vascular endothelial function.

Size and oxidative susceptibility of low-density lipoprotein particles in breast cancer patients with tamoxifen-induced fatty liver

The purpose of the present study was to investigate the effects of tamoxifen on the size and oxidative susceptibility of low-density lipoprotein (LDL) particles in breast cancer patients with tamoxifen-induced fatty liver. We investigated the following breast cancer patients: 13 receiving no tamoxifen (group A), 13 receiving tamoxifen 40 mg daily but without fatty liver (group B), and 13 receiving tamoxifen 40 mg daily with fatty liver (group C). Plasma lipids and diameter of LDL particles were measured. Susceptibility of LDL to oxidation was analyzed by incubation with CuSO(4) while monitoring conjugated diene formation and assaying thiobarbituric acid reactive substances (TBARS). Plasma total and LDL cholesterol concentrations in groups B and C were significantly lower than those in group A. In group C, concentrations of plasma triglyceride (TG) and TBARS were significantly greater, but LDL particle diameter and lag time for LDL oxidation were significantly smaller than those in groups A and B. Plasma TG concentrations correlated negatively with computed tomography ratio of liver to spleen (r = -0.76; P < 0.001). LDL particle diameter correlated negatively with plasma TG (r = -0.62; P < 0.001) and TBARS (r = -0.44; P < 0.01), but positively with LDL lag time (r = 0.47; P < 0.01). Tamoxifen-induced fatty liver in breast cancer patients may be atherogenic, via increased TG and consequent small, easily oxidized LDL particles.

Tamoxifen ("Nolvadex"): a review

Tamoxifen has been used in the management of breast cancer for over 30 years. Since its introduction for the treatment of advanced breast cancer, its indications have increased to include the treatment of early breast cancer, ductal carcinoma in situ, and more recently for breast cancer chemoprevention. Tamoxifen has a good tolerability profile and moreover, unlike many other endocrine therapies, it is efficacious in both pre- and postmenopausal women. It is the combination of efficacy and tolerability that allows tamoxifen to maintain its position as the hormonal treatment of choice for most patients with oestrogen-receptor positive breast cancer. Ongoing studies will provide further information about the optimal duration of tamoxifen therapy and how it compares with the newer aromatase inhibitors.

Use of alternative therapies in menopause

Hormone replacement therapy has traditionally been used to treat the accompanying symptoms of oestrogen deficiency in menopause. However, not all women can, or prefer to, receive this treatment and alternatives should be considered to reduce the increased risk of osteoporosis and heart disease in menopausal women. This chapter reviews the current literature on the efficacy of phyto-oestrogens in preventing cardiovascular disease, various cancers and osteoporosis, as well as treating the vasomotor and other menopause-related symptoms. Select herbal therapies, as well as selective oestrogen receptor modulators, are also considered.

The choice of hormone replacement therapy or statin therapy in the treatment of hyperlipidemic postmenopausal women

Evidence based treatment of cardiovascular risk factors on outcome in women is still inconclusive given the very large numbers needed to achieve a significant difference in cardiovascular event. Although numerous studies of the effect of hormone replacement therapy (HRT) on risk factors have suggested benefit, the only data from a randomised control trial of HRT in secondary prevention was neutral. Coronary disease-primary prevention: (a) Statins: Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TEX CAPS). The only randomised controlled trial (RCT) to include women. There were fewer coronary heart disease (CHD) events in women but no difference in mortality. (b) HRT: no completed RCT-the results from Womens Health Initiative (WHI) and Women Intervention Study of Long Duration of Oestrogen in the Menopause (WISDOM) are awaited, the former likely to complete in 2004. There are numerous reports of positive observational epidemiological studies for HRT. There is little evidence for statin use in women who will probably not qualify for treatment on global CHD risk assessment, familial hypercholesterolemia and type 2 diabetes excepted. HRT is, therefore, not only appropriate for its multiple effects on lipoproteins, vascular function and insulin sensitivity but also for prevention of osteoporosis. Coronary disease-

SECONDARY PREVENTION

(a) Statins: the major measurable effect of these drugs is to reduce total and LDL cholesterol. In RCT trials, the Scandanavian Simvastatin Survival Study (4S), the Cholesterol and Recurrent Event (CARE) and Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID), approximately 20% of subjects were female, in whom CHD events, but not CHD or total mortality were reduced. (b) HRT: there is data available from a single RCT of continuous combined premarin and medroxyprogesterone acetate (MPA) against placebo, The Heart Estrogen Replacement Study (HERS). A study of 2763 women and mean duration of 4.1 years. This study was neutral, with no reduction in CHD events or mortality. There were more events in the first year, and fewer in years 3-5. Other studies of HRT have been observational and positive for HRT. The effects of treatment on lipoproteins with statins, HRT and combination of statin and HRT have been investigated. In secondary prevention for hyperlipidemic women to achieve cholesterol <5, low density lipoprotein (LDL)<3 mmol/l statins will be first choice, possibly with HRT additionally for its other benefits on cardiovascular risk factors.

Hormone replacement therapy trials: an update

Recent randomized trials of hormone replacement therapy (HRT) in postmenopausal women are not consistent with the decrease in cardiovascular risk seen in observational studies of hormone therapy users compared with nonusers. Emerging evidence indicates that HRT use in some women with established coronary heart disease may be associated with prothrombotic effects or proinflammatory effects leading to adverse events. In healthy women, the decision to use HRT should be based primarily on noncardiac factors until more data becomes available that is relevant to this population. Several alternatives to HRT, including phytoestrogens and selective estrogen receptor modulators, have favorable effects on cardiovascular risk factors, but their impact on clinical outcomes remains to be determined.

The management of menopausal sequelae in patients with breast cancer

The use of chemotherapy and tamoxifen for young women with breast cancer results in premature menopause in a significant number of patients. Early menopause has serious vasomotor, psychological, genitourinary, cardiac and skeletal effects. Psychopharmacological and herbal preparations are widely used for the treatment of vasomotor symptoms. The incidence of psychological and depressive illness following the menopause in women with breast cancer is significantly higher than seen with the natural menopause. Targeting this population of patients for early diagnosis and psychiatric intervention is recommended. Local vaginal moisturising or oestrogen cream would help to alleviate some of the urogenital symptoms. Patients whose treatment included Anthracycline chemotherapy or radiation to the heart and those with a history of heart disease, should be monitored closely for latecardiac complications. Early menopause is the major risk factor for the development of osteoporosis. Weight bearing exercise, bisphosphonate or calcitonin therapy are all useful in treating osteoporosis. Should a woman with a history of breast cancer be given hormone replacement therapy is one of the most controversial issues in the oncology field. There are no published prospective randomised studies on the subject. The available data suggests an increase of 5% of breast cancer related events when hormone replacement therapy is given to women with breast cancer. However, in certain situations, this could be given after a detailed explanation and documentation. The patient and physician should balance the severity of symptoms against the increased breast cancer related events and the final decision should be left to the patient.

Postmenopausal hormone replacement therapy as antiatherosclerotic therapy

Cardiovascular disease remains the number one killer of women. Although important for the reduction of cardiovascular events, lipid alteration does not appear to be sufficient to obtain optimum reduction in cardiovascular risk. Women have a potential opportunity for further reduction in cardiovascular risk through postmenopausal hormone replacement therapy. More than 50 observational studies indicate that postmenopausal use of hormone replacement therapy reduces atherosclerosis and cardiovascular events. However, recently reported, randomized, controlled clinical trials have yielded mixed results as to whether hormone replacement therapy reduces cardiovascular events relative to placebo. These, as well as other randomized controlled trials of hormone replacement therapy and cardiovascular disease in postmenopausal women, are reviewed. Although conclusions concerning the specific hormones used in the specific populations studied can be offered from the completed trials, more broad conclusions concerning the use of hormone replacement therapy in the prevention of cardiovascular disease will have to await conduction and completion of other trials.

Selective estrogen receptor modulators as a new therapeutic drug group: concept to reality in a decade

This article provides an overview of the historical development, current research, clinical benefits, and potential future applications of the selective estrogen receptor modulators (SERMs), tamoxifen and raloxifene. The understanding of the mechanism of action of SERMs led not only to the development of tamoxifen, the first widely used antiestrogen for breast cancer treatment, but also to its application as a chemopreventive agent. The SERM principle of antiestrogenic actions in the breast but estrogenlike actions in bone is reviewed in clinical practice through analysis of the current applications and the potential for expanding the role of SERMs. The current view of the molecular mechanism of SERM action is summarized to identify potential target sites for future research. The clinical success of tamoxifen and raloxifene for the prevention and treatment of breast cancer and osteoporosis, respectively, has encouraged the development of a range of new agents that target breast cancer, osteoporosis, coronary heart disease, and endometrial safety.

A brief review of the International Breast Cancer Intervention Study (IBIS), the other current breast cancer prevention trials, and proposals for future trials

The available results from breast cancer chemoprevention trials are reviewed. Four trials using tamoxifen have been performed, of which three have reported efficacy results. A fifth trial using raloxifene has also been published. The largest tamoxifen trial shows approximately a 50% reduction in breast cancer incidence in the short term, but the two smaller trials have not found any incidence reduction. Greater agreement exists for side effects: thromboembolic disease and endometrial cancers are raised about 2- to 3-fold when tamoxifen is used for 5 years. The possible reasons for the discrepancy in breast cancer reduction are explored. A review of trial parameters does not clearly explain this difference, and a metanalysis indicates that all results are compatible with a 42% reduction in short-term incidence. Several important questions remain about the clinical implication of this result, including the effect on mortality, the appropriate risk groups for chemoprevention, and the long-term effects on incidence. Continued follow-up of these trials is crucial for resolving these issues.

The effects of estrogen and selective estrogen receptor modulators on cardiovascular risk factors

Raloxifene, a selective estrogen receptor modulator, favorably alters several markers of cardiovascular risk in healthy postmenopausal women. While many of its effects are similar to those of conventional hormone replacement therapy (HRT), there are also important differences. Raloxifene lowered low-density lipoprotein cholesterol levels similarly to estrogen. However, raloxifene lacked the potentially beneficial effects of HRT on high-density lipoprotein cholesterol levels and plasminogen activation inhibitor-1, as well as the potentially adverse effects of HRT on triglycerides and C-reactive protein. Raloxifene also had a potentially beneficial fibrinogen-lowering effect not seen with conventional HRT. The net effect of these differences is unclear. Proof that raloxifene or HRT reduces the risk of heart disease must await the results of ongoing clinical trials with cardiovascular event end points.

[Hormone therapy and breast cancer: a review]

PURPOSE

Tamoxifen as adjuvant hormonal therapy after hormonosensitive-breast cancer surgery is well established nowadays, as well as its efficacy in first-line therapy of advanced hormonosensitive breast cancers. Research of drugs which could be effective, with little toxicity, and having a positive impact on cardiovascular disease or bone is an important issue.

CURRENT KNOWLEDGE AND KEY POINTS

New drugs are in development or will soon be on the market to permit second or third lines of treatment with respect to effectiveness and quality of life, such as new anti-estrogens or selective estrogen receptors modulators or aromatase inhibitors. Their principal characteristics are reviewed through recent data.

FUTURE PROSPECTS AND PROJECTS

Prevention of breast cancer is a pertinent question and major publications are presented. Finally, the controversy about the possible reintroduction of replacement hormonal therapy after breast cancer will be questioned through trials.

Tamoxifen is an acute, estrogen-like, coronary vasodilator of porcine coronary arteries in vitro

Tamoxifen is a mixed estrogen antagonist and agonist. Observational data from breast cancer studies associate tamoxifen use with lesser rates of myocardial infarction. The authors sought to determine the acute vasoactive properties of tamoxifen compared with estradiol. Isolated coronary ring segments from female pigs were studied in organ baths. KCl-precontracted ring segments were exposed to increasing doses of both tamoxifen and estradiol (log-9-log-5 M ). Ring segments were also exposed to tamoxifen and estradiol in the presence of inhibitors of nitric oxide, glybenclamide, the hormone receptor antagonists ICI 182,780 and flutamide, and after de-endothelialization. Tamoxifen caused acute dilation of coronary arteries but less than estradiol. Tamoxifen-and estradiol-induced acute vasodilation was not nitric oxide- or endothelium-dependent, but was adenosine triphosphate-sensitive potassium channel-dependent. Tamoxifen-induced vasorelaxation was inhibited by antagonism of the classic estrogen receptor and antagonism of the androgen receptor with flutamide, whereas estrogen-induced vasorelaxation was inhibited partially by classic estrogen receptor antagonism but not by androgen receptor antagonism. Tamoxifen attenuated both the sensitivity of vasoconstriction to endothelin-1 and the maximal response. Tamoxifen and estradiol are both acute coronary vasodilators, with similar mechanisms of action. Tamoxifen also attenuates coronary vasoconstriction. Such properties may account for some of the observed cardiovascular clinical benefits seen in observational studies of tamoxifen use.

Breast cancer prevention: present and future

Increased risk of breast cancer may result from modifiable factors such as endogenous hormone levels, obesity, HRT, and non-lactation, or non-modifiable factors such as genetic susceptibility or increasing age. Those factors that are easiest to modify may have a limited impact on the totality of breast cancer. The Gail model, based on known factors may be useful for estimating life-time risk in some individuals. Tamoxifen prevention still remains contentious. In the NSABP-P1 study, there was a 49% reduction in risk of breast cancer in women given tamoxifen but in the Italian and Royal Marsden trials, no effect on breast cancer incidence was detected, possibly because of the different case-mix in these studies. Raloxifene, tested in the MORE trial reduced the incidence of breast cancer by 65%. The effect was restricted to ER positive tumours: no reduction in ER negative cancers was seen. Life-style factors such as diet, obesity, exercise, and age of first full term pregnancy and number of pregnancies have a mild to moderate impact on risk and so may have little effect on the incidence of breast cancer. Reduction of alcohol intake could lead to a modest reduction in the risk of breast cancer but possibly adversely affect other diseases. So far, studies of retinoids have not shown a benefit in terms of breast cancer risk reduction. Fat reduction and GnRH analogues reduce mammographic density but have not yet been shown to affect risk.

Drug-Induced lipid changes: a review of the unintended effects of some commonly used drugs on serum lipid levels

Many drugs besides lipid-lowering drugs affect serum lipid levels in either a potentially harmful or beneficial way, and may therefore increase or decrease the risk of cardiovascular disease. Diuretics, beta-blocking agents, progestogens, combined oral contraceptives containing 'second generation' progestogens, danazol, immunosuppressive agents, protease inhibitors and enzyme-inducing anticonvulsants adversely affect the lipid profile. They increase total cholesterol, low density lipoprotein cholesterol and triglycerides by up to 40, 50 and 300%, respectively, and decrease high density lipoprotein cholesterol by a maximum of 50%. Conversely, alpha-blocking agents, estrogens, hormone replacement therapy, combined oral contraceptives containing 'third generation' progestogens, selective estrogen receptor modulators, growth hormone and valproic acid show mostly beneficial effects on the lipd profile. Some drugs, for example, isotretinoin, acitretin and antipsychotics, mainly elevate triglyceride levels. Adverse or beneficial effects on serum cholesterol levels do not always translate into a higher or lower, respectively, incidence of cardiovascular disease. because these drugs may influence cardiovascular risk through multiple pathways. In some cases, excessive cholesterol levels occur, for example, with protease inhibitor therapy, and several cases of pancreatitis attributable to drug-induced hypertriglyceridaemia have been reported. Some general guidelines on the management of drug-induced dyslipidaemia can be given. Replacement of the dyslipidaemia-inducing drug by an equivalent alternative therapy is preferred. However, such alternatives are often difficult to find. If there is no equivalent alternative and treatment with the dyslipidaemia-inducing drug must be initiated, monitoring of serum lipid levels is important. If drug use is expected to be long term, the existing guidelines for the management of dyslipidaemia in the general population can be applied to drug-induced dyslipidaemia. In cases of extreme hyperlipidaemia, medication use should be reassessed.

Can tamoxifen cause a significant mammographic density change in breast parenchyma?

To evaluate tamoxifen-induced glandular tissue density changes in women who are on an adjuvant tamoxifen therapy. We examined serial mammograms of 27 women (average age 67) who had surgery for unilateral breast carcinoma and were on tamoxifen for 5 years. Mammograms obtained at the beginning of treatment, within 2 or 3 years, at the end of 5 years and 1 year after cessation of tamoxifen treatment, were evaluated by two radiologists experienced in reading mammograms. Four 1-cm-diameter circular areas of the glandular tissue and retroglandular fat were sampled by a densitometer and a relative glandular density (glandular tissue/fat density) was used for comparison between serial mammograms. Most cases (79%) did not show tamoxifen-induced change in glandular density. Three patients (13%) showed an early and two (8%) a delayed mild reduction in glandular density as compared to baseline mammograms. No patient was found to have increased glandular density following the cessation of tamoxifen therapy (in subjective evaluation). Densitometer readings showed a mild reduction in glandular densities in 16 cases (60%) during treatment and a minimal increase in 13 cases (48%) following cessation of treatment. There was a slight decrease in breast density during treatment [relative density of 0.012+/-0.006 (standard error) per interval, P value:.06] and the difference between years 5 and 6 was nearly zero [relative density of 0.00042+/-0.01 (standard error), P value:.97]. Long-term use of tamoxifen may cause a mild reduction in breast glandular density, although this, in part, may be attributed to the age-related mammographic density change. Following cessation of tamoxifen, no significant increase in glandular density was observed. Therefore, any increase in mammographic density during or after tamoxifen treatment should be viewed with suspicion and further evaluated.

Alternatives for women through menopause

Today, 42% of Americans use alternative nonprescription therapies to treat medical conditions; 46% of nonprescription alternative use for principal medical conditions is done without consulting either a medical doctor or a nonphysician practitioner of alternative therapy. Many nontraditional alternatives are used to treat the hot flashes and somatic complaints of menopause, for which options such as hormone replacement therapy and other prescription and over-the-counter drugs are also available. To date, no one agent treats all menopausal symptoms as effectively as estrogen. Selective estrogen-receptor modulators can help prevent osteoporosis but do not relieve menopausal symptoms. However, some women are unwilling or unable to take hormone replacement therapy, and some decide to discontinue therapy. Evidence supporting the use of some nonprescription alternatives for conditions related to menopause is limited. Patients need to be aware of the potential for drug interactions when these alternative therapies are used concomitantly with prescription drugs. The current evidence to support use of hormone replacement therapy, selective estrogen-receptor modulators, and nontraditional alternatives is reviewed here.

Tamoxifen, esterified estradiol, and physiologic concentrations of estradiol inhibit oxidation of low-density lipoprotein by endothelial cells

OBJECTIVE

We investigated the antioxidant effect of tamoxifen, esterified estradiol, and physiologic concentrations of 17beta-estradiol on endothelial cell-mediated oxidation of low-density lipoprotein.

STUDY DESIGN

Human umbilical vein endothelial cells were preincubated with nanomolar concentrations of estradiol, estradiol stearate, and tamoxifen. Low-density lipoprotein was isolated and incubated with cells in serum-free medium. Oxidation of low-density lipoprotein was quantified after 8, 16, and 24 hours of incubation as the formation of thiobarbituric acid-reactive substances.

RESULTS

Compared with control, preincubation of human umbilical vein endothelial cells with 1- or 10-nmol/L estradiol resulted in a 12% reduction in the formation of thiobarbituric acid-reactive substances at 24 hours. Preincubation of human umbilical vein endothelial cells with either 10-nmol/L estradiol 17-stearate or 10-nmol/L tamoxifen resulted in 26% and 20% decreases, respectively, in formation of thiobarbituric acid-reactive substances at 24 hours. The difference in the reduction in thiobarbituric acid-reactive substances between control and treatment wells became more pronounced over time.

CONCLUSION

Under these experimental conditions, tamoxifen, esterified estradiol, and physiologic concentrations of exogenous estradiol inhibit oxidation of low-density lipoprotein by human umbilical vein endothelial cells.

Tamoxifen effects on endothelial function and cardiovascular risk factors in men with advanced atherosclerosis

BACKGROUND

Tamoxifen and its analogues act as selective estrogen receptor modulators (SERMs) in women, with estrogen-like activities on some plasma cardiovascular risk factors (eg, lipoproteins). Effects of SERMs on men with coronary artery disease (CAD) have not been reported.

METHODS AND RESULTS

Thirty-one men with angiographically proven CAD were recruited; 16 were treated with tamoxifen (40 mg/d) for 56 days, and 15 were untreated. All the CAD patients were medicated with aspirin and an HMG-CoA reductase inhibitor for >/=6 weeks before entering the study. Ten men with angina-like symptoms but normal coronary arteries by angiography (NCA group) were also treated with tamoxifen. Blood samples were collected at days -7, 0, 7, 14, 21, 28, and 56 of treatment. Endothelium-dependent flow-mediated dilatation (ED-FMD) of the brachial artery was measured by high-resolution ultrasound at 5 visits. Tamoxifen caused an increase in %ED-FMD maximal at 28 days in the CAD group (2.1+/-0.3% to 7.5+/-0.7%; P<0.0001) and the NCA group (3.8+/-0.4% to 7.9+/-1.0%; P<0.0001), with no significant change in the untreated group. Tamoxifen also caused decreases in several plasma cardiovascular risk factors, including total cholesterol, triglycerides, lipoprotein(a), and fibrinogen. Except for the triglyceride response, these effects were similar to those reported for postmenopausal women treated with tamoxifen.

CONCLUSIONS

Tamoxifen substantially increased ED-FMD in men with CAD who were taking conventional medication. Together with the effects on risk factors, the data strongly support clinical evaluation of SERMs for the treatment of men with CAD.

The latent transforming growth factor beta binding protein (LTBP) family

The transforming growth factor beta (TGFbeta) cytokines are a multi-functional family that exert a wide variety of effects on both normal and transformed mammalian cells. The secretion and activation of TGFbetas is regulated by their association with latency-associated proteins and latent TGFbeta binding proteins (LTBPs). Over the past few years, three members of the LTBP family have been identified, in addition to the protoype LTBP1 first sequenced in 1990. Three of the LTBP family are expressed in a variety of isoforms as a consequence of alternative splicing. This review summarizes the differences between the isoforms in terms of the effects on domain structure and hence possible function. The close identity between LTBPs and members of the fibrillin family, mutations in which have been linked directly to Marfan's syndrome, suggests that anomalous expression of LTBPs may be associated with disease. Recent data indicating that differential expression of LTBP1 isoforms occurs during the development of coronary heart disease is considered, together with evidence that modulation of LTBP function, and hence of TGFbeta activity, is associated with a variety of cancers.