Invasive lobular breast cancer and its variants: How special are they for systemic therapy decisions?

The WHO classification of breast tumors distinguishes, besides invasive breast cancer ‘of no special type’ (former invasive ductal carcinoma, representing 60–70% of all breast cancers), 30 special types, of which invasive lobular carcinoma (ILC) is the most common (5–15%). We review the literature on (i) the specificity and heterogeneity of ILC biology as documented by various analytical techniques, including the results of molecular testing for risk of recurrence; (ii) the impact of lobular histology on prediction of prognosis and effect of systemic therapies in patients. Though it is generally admitted that ILC has a better prognosis than IDC, is endocrine responsive, and responds poorly to chemotherapy, currently available data do not unanimously support these assumptions. This review demonstrates some lack of specific data and a need for improving clinical research design to allow oncologists to make informed systemic therapy decisions in patients with ILC. Importantly, future studies should compare various endpoints in ILC breast cancer patients among the group of hormonosensitive breast cancer.     

Effect of estrogen plus progestin on risk for biliary tract surgery in postmenopausal women with coronary artery disease. The Heart and Estrogen/progestin Replacement Study

BACKGROUND: Animal and observational epidemiologic studies have reported that estrogens may increase the risk for gallstones. No major clinical trials have examined the effect of estrogen plus progestin therapy in postmenopausal women on the risk for biliary tract surgery. OBJECTIVE: To determine the effect of estrogen plus progestin on the risk for biliary tract surgery in postmenopausal women with known coronary artery disease. DESIGN: Randomized, double-blind placebo-controlled trial of postmenopausal hormone therapy for coronary heart disease. SETTING: 20 U.S. clinical centers. PARTICIPANTS: 2253 postmenopausal women with a gallbladder, 44 to 79 years of age at baseline, in the Heart and Estrogen/progestin Replacement Study (HERS). INTERVENTION: Conjugated equine estrogens, 0.625 mg, plus medroxyprogesterone acetate, 2.5 mg, daily in one tablet or identical placebo. MEASUREMENTS: Documented biliary tract surgery. RESULTS: A total of 147 women (7%) were hospitalized for biliary tract surgery in HERS. Treatment with estrogen plus progestin resulted in a marginally significant 38% increase in the relative risk for biliary tract surgery (P = 0.05). A small absolute difference in risk suggested that for every 185 women treated with estrogen plus progestin, one additional woman had biliary tract surgery per year. After adjustment for baseline and in-study statin use, the association was attenuated further (P = 0.09). After adjustment for treatment assignment and other variables, increased body mass index, fibric acid use, and a history of nonsurgical gallbladder disease were associated with an increased risk for biliary tract surgery, whereas statin use was associated with a decreased risk (for each comparison, P < 0.05). CONCLUSION: Estrogen plus progestin therapy among postmenopausal women with known coronary disease resulted in a marginally significant increase in the risk for biliary tract surgery.     

A prospective study of female hormone use and breast cancer among black women

BACKGROUND: Epidemiologic studies, largely of white women, have found that recent long-term female hormone use, particularly use of estrogen with progestin, is associated with an increased risk of breast cancer. Some studies suggest that the increase is greater among leaner women. Our aim was to assess the relation of female hormone use to incidence of breast cancer in black women, with attention to differences in effect according to body mass index. METHODS: Data on female hormone use, breast cancer risk factors, and the occurrence of breast cancer were collected through biennial questionnaires from 1995 through 2003 in the Black Women's Health Study, a follow-up study of US black women. During 182 629 person-years of follow-up of 32 559 women 40 years or older, 615 cases of breast cancer were reported. RESULTS: The incidence rate ratio for breast cancer in women recently using female hormone supplements relative to those who had never used female hormones, with control for confounding factors, increased with duration of use and was 1.58 (95% confidence interval [CI], 1.12-2.23) for 10 or more years of use; the incidence rate ratios were 1.41 (95% CI, 0.95-2.10) for 10 or more years of use of estrogen alone, and 1.45 (95% CI, 0.94-2.23) for 5 or more years of use of estrogen with progestin. The association of breast cancer with female hormone use was stronger among leaner women (body mass index [calculated as weight in kilograms divided by the square of height in meters] <25) than among heavier women. Among the leaner women who recently used female hormone supplements for durations of 10 or more years, the incidence rate ratio was 3.08 (95% CI, 1.70-5.56); the corresponding estimates among women with body mass indexes of 25 to 29 and 30 or greater were 1.43 and 0.91, respectively, and neither was statistically significant. CONCLUSION: These results based on data from US black women strengthen the evidence that use of estrogen alone and estrogen with progestin increases the risk of breast cancer and that the association is stronger among leaner women.     

Venous thrombosis and conjugated equine estrogen in women without a uterus

BACKGROUND: Postmenopausal hormone therapy has been associated with a 2- to 3-fold increased risk of venous thromboembolism (VT) (including deep vein thrombosis and pulmonary embolism) in observational studies and secondary prevention clinical trials. Clinical trial data on the effects of estrogen alone on VT are limited. METHODS: The Women's Health Initiative estrogen trial enrolled 10 739 women aged 50 to 79 years without a uterus. Participants were randomly assigned to receive conjugated equine estrogen (0.625 mg/d) or placebo. RESULTS: During a mean of 7.1 years, VT occurred in 111 women randomly assigned to receive estrogen (3.0 per 1000 person-years) and 86 randomly assigned to receive placebo (2.2 per 1000 person-years; hazard ratio, 1.32; 95% confidence interval, 0.99-1.75). Deep venous thrombosis was reported in 85 women randomly assigned to receive estrogen (2.3 per 1000 person-years) and 59 randomly assigned to receive placebo (1.5 per 1000 person-years; hazard ratio, 1.47; 95% confidence interval, 1.06-2.06). The VT risk was highest in the first 2 years. There were no significant interactions between estrogen use and age, body mass index, or most other VT risk factors. Comparison of Women's Health Initiative VT findings for estrogen and previous Women's Health Initiative findings for estrogen plus progestin showed that the hazard ratios for estrogen plus progestin were significantly higher than those for estrogen alone (P = .03), even after adjusting for VT risk factors. CONCLUSION: An early increased VT risk is associated with use of estrogen, especially within the first 2 years, but this risk increase is less than that for estrogen plus progestin.     

Who should receive hormone replacement therapy?

Coronary heart disease is the leading cause of death in women in the United States and increases dramatically in postmenopausal women. The following review summarizes the known benefits and risks of hormone replacement therapy and gives recommendations for use of hormone replacement in women. Estrogen may play a role in preventing the development of atherosclerosis in women by raising levels of HDL cholesterol, lowering levels of LDL cholesterol and lipoprotein (a), lowering levels of fibrinogen and plasminogen activator inhibitor-1, dilating coronary arteries, preventing the oxidation of LDL cholesterol, decreasing the proliferation and migration of smooth muscle cells, and decreasing the production of inflammatory cell activators. These anti-atherogenic effects of estrogen may translate into clinical benefits. A meta-analysis of 31 studies yielded a 44% reduction in the risk of coronary heart disease in women taking estrogen alone. Unopposed estrogen is associated with an increased risk of endometrial cancer; therefore, progestin is added to estrogen in women with an intact uterus. Less is known about the effect of the combination of estrogen and a progestin on the risk of coronary heart disease. Estrogen is also beneficial in the prevention of osteoporosis; however, long-term use of estrogen alone and estrogen in combination with progestin may increase the risk for breast cancer. Mathematical modeling predicted that women with no risk for cardiovascular disease, cancer, or osteoporosis may gain 0.9 years of life with the use of estrogen alone; women with risk factors for cardiovascular disease can expect to gain 1.5 years of life; and women with coronary heart disease at the age of 50 can expect to gain 2.1 years of life. The current American College of Physicians recommendations for hormone replacement are as follows: (1) All women should be considered; (2) women with a hysterectomy should receive estrogen alone; (3) women at risk for, or with, coronary heart disease are most likely to benefit from estrogen; with an intact uterus, progestin must be added; (4) risks of estrogen may outweigh benefits in women at increased risk for breast cancer. Definitive guidelines for the treatment of women must await the results of randomized clinical trials in the ongoing Women's Health Initiative. These will not be available for several years, and until then any recommendations for women will have to be judged from estimates of risk rather than of benefit from reduction of risk. The decision whether to initiate estrogen replacement in postmenopausal women is one that still needs to be made on an individual patient basis.Supported by NHLBI grant HL 02626. Dr. Welty is the 1995 recipient of the Alpha Phi Foundation Award.     

Increased incidence of lobular breast cancer in women treated with hormone replacement therapy: implications for diagnosis, surgical and medical treatment

A growing body of evidence support the association between the use of hormone replacement therapy (HRT) and a higher risk of both invasive lobular carcinoma (ILC) and invasive ductal-lobular mixed carcinoma (IDLC). Overall biological and clinical features of ILC entail a more cautious diagnostic and therapeutic approach as compared with invasive ductal carcinoma (IDC). ILCs are more frequently multifocal, multicentric and/or bilateral. Mammography and ultrasound show, therefore, significant limitations, while the higher sensitivity of magnetic resonance imaging in the detection of multifocal and/or multicentric lesions seems to improve the accuracy of preoperative staging of ILCs. Early diagnosis is even more challenging because the difficult in the localization and the sparse cellularity of lobular tumours may determine a false negative core biopsy. ILC is characterized by low proliferative activity, C-ErbB-2 negativity, bcl-2 positivity, p53 and VEGF negativity, oestrogen and progesterone positive receptors, low grade and low likelihood of lymphatic-vascular invasion. However, this more favourable biological behaviour does not reflect into a better disease-free and overall survival as compared with IDC. Since lobular histology is associated with a higher risk of positive margins, mastectomy is often preferred to breast conservative surgery. Moreover, only few patients with ILC achieve a pathologic response to preoperative chemotherapy and, therefore, in most patients mastectomy can be regarded as the safer surgical treatment. The preoperative staging and the follow-up of patients with ILC are also complicated by the particular metastatic pattern of such histotype. In fact, metastases are more frequently distributed to the gastrointestinal tract, peritoneum/retroperitoneum and gynaecological organs than in IDC.     

Unopposed estrogen therapy and the risk of invasive breast cancer

BACKGROUND: Although short-term unopposed estrogen use does not seem to increase breast cancer risk, the effect of longer-term estrogen use remains unclear. We sought to assess the relationship between longer-term use of unopposed estrogen and the risk of invasive breast cancer over an extended follow-up period. METHODS: Within the Nurses' Health Study, a prospective cohort study, we observed 11 508 postmenopausal women who had a hysterectomy and reported information on estrogen use at baseline (1980). The study population was expanded every 2 years to include women who subsequently became postmenopausal and had a hysterectomy, so that 28 835 women were included in the final follow-up period (2000-2002). Estrogen use was assessed from self-reported data on biennial questionnaires. The main outcome was invasive breast cancer. RESULTS: A total of 934 invasive breast cancers were included in the analysis. Breast cancer risk increased with duration of unopposed estrogen use among longer-term users with the highest risk seen in cancers positive for estrogen receptor (ER+) and progesterone receptor (PR+). The multivariate relative risks (RRs) and 95% confidence intervals (CIs) for breast cancer with current use of unopposed estrogen for less than 5 years, 5 to 9.9 years, 10 to 14.9 years, 15 to 19.9 years, and 20 years or longer were, respectively, 0.96 (95% CI, 0.75-1.22), 0.90 (95% CI, 0.73-1.12), 1.06 (95% CI, 0.87-1.30), 1.18 (95% CI, 0.95-1.48), and 1.42 (95% CI, 1.13-1.77) (P for trend <.001). The risk of ER+/PR+ breast cancers was noted to be statistically significant after 15 years of current use (RR, 1.48; 95% CI, 1.05-2.07). CONCLUSION: Users of unopposed estrogen were at increased risk of breast cancer but only after longer-term use.     

Prospective study of leukocyte count as a predictor of incident breast, colorectal, endometrial, and lung cancer and mortality in postmenopausal women

BACKGROUND: The immune system and inflammation are implicated in the pathogenesis of cancer. Prospective studies linking biomarkers of inflammation with cancer incidence and mortality have been inconclusive. METHODS: To determine whether there is an independent association of white blood cell (WBC) count with incident cancer in postmenopausal women, a prospective cohort study was performed at 40 US clinical centers involving 143,748 postmenopausal women aged 50 to 79 years who were free of cancer at baseline and were enrolled in the Women's Health Initiative. The main outcome measures were incident invasive breast, colorectal, endometrial, and lung cancer. RESULTS: In multivariate models, there was a graded association of WBC count with incidence of all 4 types of cancer. Compared with the lowest quartile of WBC count (2.50-4.79x10(9) cells/L), women with a WBC count in the upper quartile (6.80-15.00x10(9) cells/L) had a statistically significantly higher risk of invasive breast cancer (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.04-1.26), colorectal cancer (HR, 1.19; 95% CI, 1.00-1.41), endometrial cancer (HR, 1.42; 95% CI, 1.12-1.79), and lung cancer (HR, 1.63; 95% CI, 1.35-1.97). The findings were similar when cancers that occurred during the first 2 years of follow-up were excluded. Statistically significant associations remained for invasive breast cancer and endometrial cancer when the analyses were limited to nonsmokers. The WBC count was also statistically significantly associated with breast cancer, lung cancer, and overall cancer mortality. CONCLUSION: Postmenopausal women with higher WBC counts have a higher risk of incident invasive breast, colorectal, endometrial, and lung cancer, as well as a higher risk of breast, lung, and overall cancer mortality.     

Combined estrogen and testosterone use and risk of breast cancer in postmenopausal women

BACKGROUND: The role of androgens in breast cancer etiology has been unclear. Epidemiologic studies suggest that endogenous testosterone levels are positively associated with breast cancer risk in postmenopausal women. Given the increasing trend in the use of hormone therapies containing androgens, we evaluated the relation between the use of estrogen and testosterone therapies and breast cancer. METHODS: We conducted a prospective cohort study in the Nurses' Health Study from 1978 to 2002 to assess the risk of breast cancer associated with different types of postmenopausal hormone (PMH) formulations containing testosterone. During 24 years of follow-up (1 359 323 person-years), 4610 incident cases of invasive breast cancer were identified among postmenopausal women. Information on menopausal status, PMH use, and breast cancer diagnosis was updated every 2 years through questionnaires. RESULTS: Among women with a natural menopause, the risk of breast cancer was nearly 2.5-fold greater among current users of estrogen plus testosterone therapies (multivariate relative risk, 2.48; 95% confidence interval, 1.53-4.04) than among never users of PMHs. This analysis showed that risk of breast cancer associated with current use of estrogen and testosterone therapy was significantly greater compared with estrogen-only therapy (P for heterogeneity, .007) and marginally greater than estrogen and progesterone therapy (P for heterogeneity, .11). Women receiving PMHs with testosterone had a 17.2% (95% confidence interval, 6.7%-28.7%) increased risk of breast cancer per year of use. CONCLUSION: Consistent with the elevation in risk for endogenous testosterone levels, women using estrogen and testosterone therapies have a significantly increased risk of invasive breast cancer.     

Hormone therapy to prevent disease and prolong life in postmenopausal women.

PURPOSE: To critically review the risks and benefits of hormone therapy for asymptomatic postmenopausal women who are considering long-term hormone therapy to prevent disease or to prolong life. DATA SOURCES: Review of the English-language literature since 1970 on the effect of estrogen therapy and estrogen plus progestin therapy on endometrial cancer, breast cancer, coronary heart disease, osteoporosis, and stroke. We used standard meta-analytic statistical methods to pool estimates from studies to determine summary relative risks for these diseases in hormone users and modified lifetable methods to estimate changes in lifetime probability and life expectancy due to use of hormone regimens. RESULTS: There is evidence that estrogen therapy decreases risk for coronary heart disease and for hip fracture, but long-term estrogen therapy increases risk for endometrial cancer and may be associated with a small increase in risk for breast cancer. The increase in endometrial cancer risk can probably be avoided by adding a progestin to the estrogen regimen for women who have a uterus, but the effects of combination hormones on risk for other diseases has not been adequately studied. We present estimates for changes in lifetime probabilities of disease and life expectancy due to hormone therapy in women who have had a hysterectomy; with coronary heart disease; and at increased risk for coronary heart disease, hip fracture, and breast cancer. CONCLUSIONS: Hormone therapy should probably be recommended for women who have had a hysterectomy and for those with coronary heart disease or at high risk for coronary heart disease. For other women, the best course of action is unclear.     

Neoplasia of the female reproductive tract: effects of hormone therapy

This review presents the data on the relationship between estrogen and estrogen plus progestin therapy in postmenopausal women and the occurrence of neoplasia in the endometrium, ovary, and uterine cervix. Estrogen only in women with an intact uterus consistently is shown to increase the incidence of endometrial cancer. Estrogen plus a cyclic or sequential progestin reduces the incidence of endometrial cancer to that found in never users. The duration of the progestin administration appears to be important with less than 10 d of progestin having an increased incidence of cancer after 5 yr of therapy. Continuous estrogen plus progestin does not increase the incidence of endometrial cancer. Estrogen and estrogen plus progestin effects on the occurrence of ovarian cancer are inconsistent. The data suggest a possible increase in ovarian epithelial tumors with >10 years use of estrogen only. There is no evidence of a change in the incidence of uterine cervical neoplasia with either estrogen or progestin.     

Hormone replacement therapy in clinical cardiology

The relationship between coronary heart disease (CHD) and menopause remains controversial, but observational studies of hormone replacement therapy among postmenopausal women have found a lower risk of CHD among women taking postmenopausal estrogens or estrogen/progestin combination therapy. In contrast, the Heart and Estrogen/progestin Replacement Study (HERS) did not show any overall benefit of estrogen/progestin therapy over 4.1 years of follow-up in a sample of women with established CHD, despite the expected favorable changes in the participants' lipid profiles. There appeared to be an initial increase in CHD risk, but benefit with increasing duration of hormone use. More research on the relative benefits and risks of hormone replacement therapy in postmenopausal women is needed. For now, a cautionary approach to hormone replacement therapy appears warranted, at least among postmenopausal women with established coronary artery disease.     

Is screening mammography effective in elderly women

PURPOSE: Screening mammography is effective in reducing breast cancer mortality in women between the ages of 50 and 69 years. We sought to determine whether older women who undergo screening mammography have a decreased risk of metastatic breast cancer. SUBJECTS AND METHODS: We studied 690,993 women aged 66 to 79 years who were California Medicare beneficiaries from January 1992 to December 1993, and who chose the fee-for-service plan. Health Care Financing Administration part B billing records were used to determine the use of screening mammography. The extent of breast cancer (in situ, local, regional, or metastatic) was ascertained for the 6,767 women who were diagnosed with the disease in 1993, using data from the California State Cancer Registry. For each type (extent) of breast cancer, the relative risk (RR) and 95% confidence (CI) of developing breast cancer was estimated by dividing the risk of its development in screened women by the risk in women who were not screened. RESULTS: A total of 46% of women had mammography during the 2-year study period. In situ, local, and regional breast cancer were more likely to be detected among women who underwent screening mammography. For example, the relative risk of detecting local breast cancer in screened women was 3.3 (95% CI: 3.1 to 3.5). The risk of detecting metastatic breast cancer, on the other hand, was significantly reduced among women aged 66 to 79 years who underwent screening mammography (RR = 0.57, 95% CI: 0.45 to 0.72). CONCLUSION: Screening mammography is associated with a decreased risk of detecting metastatic breast cancer among elderly women. Public health recommendations need to weigh the benefit of screening elderly women against the cost and potential harm from screening and treating early lesions that may have no effect on mortality.     

Effect of genistein on endothelial function in postmenopausal women: a randomized,double-blind,controlled study

PURPOSE: Genistein, a phytoestrogen found in soybeans, corrects endothelial dysfunction induced by oophorectomy in animals. Using a double-blind, controlled, randomized design, we evaluated its effects on endothelial function in women. METHODS: We enrolled 79 healthy postmenopausal women (mean [+/- SD] age, 56 +/- 4 years) and randomly assigned them to receive continuous estrogen/progestin therapy (n = 26; 17beta-estradiol [1 mg/d] combined with norethisterone acetate [0.5 mg/d]), genistein (n = 27; 54 mg/d), or placebo (n = 26). Brachial artery flow-mediated, endothelium-dependent vasodilation and plasma levels of nitrites/nitrates (a marker of nitric oxide metabolism) and endothelin-1 were measured at baseline and after 1 year of therapy. RESULTS: Treatment with genistein increased levels of nitrites/nitrates (mean increase, 21 micromol/L; 95% confidence interval [CI]: 15 to 26 micromol/L; P <0.001 vs. placebo); estrogen/progestin therapy caused similar changes (P <0.001 vs. placebo). Plasma endothelin-1 levels decreased following 12 months of genistein (mean decrease, 7 pg/mL; 95% CI: 3 to 10 pg/mL; P <0.001 vs. placebo) and after 12 months of estrogen/progestin (P <0.001 vs. placebo). When compared with placebo, brachial artery flow-mediated dilation was improved by genistein (mean increase, 5.5%; 95% CI: 3.9% to 7.0%; P <0.001) and by estrogen/progestin (P <0.001). There were no significant differences between estrogen and genistein for any of these parameters (all P >0.4). CONCLUSION: One year of genistein therapy improves endothelium function in postmenopausal women to a similar extent as does an estrogen/progestin regimen.     

Exogenous estrogen and endogenous sex hormones.

Estrogen replacement therapy is widely used to treat menopausal symptoms and prevent osteoporosis. The mechanism of these and other estrogen effects is currently under investigation. We studied the plasma steroid hormone and sex hormone binding globulin levels in frozen plasma obtained from 977 women aged 50 to 79 years from 1972 to 1974. Almost all of the 301 women who reported current use of noncontraceptive estrogen were taking conjugated estrogen by mouth; none reported use of a progestin. Women taking estrogen were significantly younger, thinner, and more likely to smoke cigarettes than women not taking estrogen. Sex hormone binding globulin and all endogenous hormones except testosterone were negatively correlated with age; estradiol was positively and cortisol and sex hormone binding globulin were negatively associated with obesity. After adjusting for age and obesity, dehydroepiandrosterone sulfate, androstenedione, and free testosterone were significantly lower in women currently taking estrogen than in women not using estrogen. These differences were independent of cigarette smoking. As expected, estrogens (including free estradiol), sex hormone binding globulin, and cortisol levels were higher in treated than untreated women. The possibility that some of the benefits and risks of replacement estrogen are secondary to altered adrenal steroid metabolism and androgen levels needs further evaluation.     

Postmenopausal hormone therapy and atherosclerotic disease

Several lines of evidence suggest that estrogen is an important determinant of cardiovascular risk in women. Epidemiologic data document low rates of coronary heart disease (CHD) in premenopausal women, a narrowing of the gender gap in CHD mortality after menopause, and elevated risk of CHD among young women with bilateral oophorectomy not treated with estrogen. Nearly all of the more than 30 observational studies of exogenous estrogen replacement therapy have indicated a reduced risk of CHD among women receiving estrogen therapy. In a meta-analysis comparing estrogen users and nonusers, the estimated reduction of CHD among users was 44%. In angiographic studies, women taking estrogen were less likely to have coronary artery stenosis. Estrogen is known to affect a wide range of physiologic processes that may have an impact on CHD risk. Use of oral estrogen has favorable effects on serum lipid profiles; it increases high-density lipoprotein cholesterol levels by 10% to 15% and decreases low-density lipoprotein cholesterol levels by a similar magnitude. Other proposed mechanisms include inhibition of endothelial hyperplasia, reduced arterial impedance, enhanced production of prostacyclin, increased insulin sensitivity, and inhibition of oxidation of low-density lipoprotein. Nevertheless, the role of hormone replacement therapy in preventing clinical atherosclerotic events in women remains inconclusive because of the absence of randomized trial data. The benefit-to-risk ratio must be reliably assessed, because estrogen has complex actions, including postulated benefits (CHD, osteoporosis, and menopausal symptoms) and postulated risks (endometrial cancer, breast cancer, and gallstones). Furthermore, the addition of a progestin, which is commonly given to protect the endometrium, may attenuate the lipid benefits of estrogen; the benefit-to-risk ratio of such a combined regimen is even less certain. The Women's Health Initiative, a recently launched large-scale randomized trial of estrogen, estrogen-progestin, and placebo, as well as other ongoing randomized trials, will provide invaluable information to aid postmenopausal women in making the complex decision about whether to take hormone replacement therapy.     

Adiposity as a risk determinant for postmenopausal breast cancer

BACKGROUND: Cross-cultural studies have long suggested that the high incidence of breast cancer in developed Western countries may be linked to the high prevalence of obesity and to high total energy intake. Recent studies show that hyperinsulinemia, increased concentration of insulin-like growth factor 1 and greater abdominal fat accumulation are markers of high risk for breast cancer. Increased serum concentrations of free estradiol and free testosterone are similar risk markers and are frequent concomitants of hyperinsulinemia. MECHANISMS: The mechanism by which such metabolic-endocrine abnormality may promote mammary carcinogenesis is uncertain, but its effect is likely to predominate in the years approaching the menopause when obesity is common among Western women. In obese subjects, enlargement of adipose deposits is known to produce an excess of free fatty acids and tumor necrosis factor alpha, both of which may be involved in the pathogenesis of insulin resistance. In middle-aged women, the concomitants of hyperinsulinemia may activate invasive and proliferative activity in preneoplastic mammary lesions such as in situ duct carcinoma of the comedo type. This will enhance the risk of progression to invasive breast cancer, which is likely to manifest clinically mainly after the menopause. CONCLUSION: Weight reduction combined with a program of regular physical exercise has been shown to reduce both estrogen and insulin concentrations in obese women and such a regimen might be tested in clinical trials for an effect on breast cancer risk in obese women. Intervention is best begun around the age of 45 y, this being the age when in situ duct carcinoma would normally begin to show evidence of spontaneous involution in women without clinical evidence of invasive breast cancer. International Journal of Obesity (2000) 24, 527-533     

Effect of hormone therapy on mortality rates among women with heart failure and coronary artery disease

Randomized, controlled trial data from the Heart and Estrogen-progestin Replacement Study were used to evaluate the effect of estrogen plus progestin use on all-cause mortality in women with heart failure and coronary disease. Over the 4.1-year follow-up, estrogen plus progestin use had no effect on all-cause mortality (hazard ratio 1.0, 95% confidence interval 0.7 to 1.4, p = 0.8) in women with heart failure and coronary disease.     

Aortic plaque size and endometrial response in cholesterol-fed rabbits treated with estrogen plus continuous or sequential progestin.

ERT is associated with a reduced incidence of coronary risk and cardiac events in postmenopausal women, but increases the risk of endometrial hyperplasia and carcinoma. Combined estrogen and progestin therapy protects the endometrium; however, its effects on heart disease risk factors are not completely known. In our study, 56 ovariectomized New Zealand White rabbits in 7 groups received a 0.5% cholesterol diet for 12 weeks. Controls were not treated with hormones. All other animals received (per kilogram body weight per week) intramuscular injections of either 0.3 mg estrogen (estradiol valerate) alone, 8.3 mg progestin (hydroxyprogesterone caproate) alone, estrogen and progestin continuously in 3 different dosages (0.3 and 8.3 mg; 1 and 8.3 mg; or 1 and 2.8 mg; estrogen and progestin, respectively), or 1 mg estrogen with 25 mg progestin sequentially in 2-week cycles. Eight non-ovariectomized animals served as further controls for endometrial analysis. Morphometric analysis of plaque size in the aortic arch showed that estrogen monotherapy, and the 3 combined therapies with 1 mg estrogen, significantly reduced intimal thickening (P<0.05). The application of progestin alone had no effect on plaque size. The endometrium was enlarged by 3-fold after estrogen treatment, and was decreased by half after progestin treatment, compared with control uteri (P<0.05). In all groups with combined hormone regimens, endometrial size was not significantly different from control uteri. However, these uteri showed more inflammatory reactions, especially when higher doses of hormones were given. In this animal model, doses of progestin that are able to successfully reduce the proliferative effect of estrogen on endometrium do not diminish the desirable antiatherosclerotic properties of estrogen.     

Natural progesterone, but not medroxyprogesterone acetate, enhances the beneficial effect of estrogen on exercise-induced myocardial ischemia in postmenopausal women

OBJECTIVES

We sought to compare the effects of estrogen/transvaginal progesterone gel with estrogen/medroxyprogesterone acetate (MPA) on exercise-induced myocardial ischemia in postmenopausal women with coronary artery disease or previous myocardial infarction, or both.

BACKGROUND

Estrogen therapy beneficially affects exercise-induced myocardial ischemia in postmenopausal women; however, women with an intact uterus also take progestin to protect against uterine malignancies. The effects of combination estrogen/progestin therapy on myocardial ischemia are unknown.

METHODS

Eighteen postmenopausal women (mean ± SD age 59 ± 7 years) were given 17-beta-estradiol in single-blinded manner for four weeks (1 mg/day for three weeks then 2 mg/day for one week). Estradiol (2 mg/day) was then continued, and the patients were randomized (double-blind) for 12 days to either transvaginal progesterone gel (90 mg on alternate days) and oral MPA placebo (10 mg/day), or vice versa. After another two weeks on estradiol alone, the patients crossed over to progestin treatment and repeated the protocol on the opposite treatment. Patients underwent treadmill exercise testing after each estradiol phase and at day 10 of each progestin phase.

RESULTS

Exercise time to myocardial ischemia increased after the first estrogen phase as compared with baseline (mean difference with 95% confidence interval [CI]: 72 s [34 to 110], P = 0.001), and was increased by combination estradiol/progesterone therapy as compared with estradiol/MPA therapy (92 s [35 to 149], P = 0.001)). Two patients (11%) were withdrawn while taking estradiol/MPA owing to unstable angina.

CONCLUSIONS

Combination estrogen/transvaginal progesterone gel increases exercise time to myocardial ischemia, as compared with estrogen/MPA. These results imply that the choice of progestin in women at higher cardiovascular risk requires careful consideration.