Estrogen plus progestin therapy and breast cancer in recently postmenopausal women

A Framework for Descriptive Epidemiology

In this paper, we propose a framework for thinking through the design and conduct of descriptive epidemiologic studies. A well-defined descriptive question aims to quantify and characterize some feature of the health of a population and must clearly state: 1) the target population, characterized by person and place, and anchored in time; 2) the outcome, event, or health state or characteristic; and 3) the measure of occurrence that will be used to summarize the outcome (e.g., incidence, prevalence, average time to event, etc.). Additionally, 4) any auxiliary variables will be prespecified and their roles as stratification factors (to characterize the outcome distribution) or nuisance variables (to be standardized over) will be stated. We illustrate application of this framework to describe the prevalence of viral suppression on December 31, 2019, among people living with human immunodeficiency virus (HIV) who had been linked to HIV care in the United States. Application of this framework highlights biases that may arise from missing data, especially 1) differences between the target population and the analytical sample; 2) measurement error; 3) competing events, late entries, loss to follow-up, and inappropriate interpretation of the chosen measure of outcome occurrence; and 4) inappropriate adjustment.

Hormone therapy in the postmenopausal years: considering benefits and risks in clinical practice

BACKGROUND

Menopausal symptoms can be very distressing and considerably affect a woman's personal and social life. It is becoming more and more evident that leaving bothersome symptoms untreated in midlife may lead to altered quality of life, reduced work productivity and, possibly, overall impaired health. Hormone therapy (HT) for the relief of menopausal symptoms has been the object of much controversy over the past two decades. At the beginning of the century, a shadow was cast on the use of HT owing to the concern for cardiovascular and cerebrovascular risks, and breast cancer, arising following publication of a large randomized placebo-controlled trial. Findings of a subanalysis of the trial data and extended follow-up studies, along with other more modern clinical trials and observational studies, have provided new evidence on the effects of HT.

OBJECTIVE AND RATIONALE

The goal of the following paper is to appraise the most significant clinical literature on the effects of hormones in postmenopausal women, and to report the benefits and risks of HT for the relief of menopausal symptoms.

SEARCH METHODS

A Pubmed search of clinical trials was performed using the following terms: estrogens, progestogens, bazedoxifene, tibolone, selective estrogen receptor modulators, tissue-selective estrogen complex, androgens, and menopause.

OUTCOMES

HT is an effective treatment for bothersome menopausal vasomotor symptoms, genitourinary syndrome, and prevention of osteoporotic fractures. Women should be made aware that there is a small increased risk of stroke that tends to persist over the years as well as breast cancer risk with long-term estrogen-progestin use. However, healthy women who begin HT soon after menopause will probably earn more benefit than harm from the treatment. HT can improve bothersome symptoms, all the while conferring offset benefits such as cardiovascular risk reduction, an increase in bone mineral density and a reduction in bone fracture risk. Moreover, a decrease in colorectal cancer risk is obtainable in women treated with estrogen-progestin therapy, and an overall but nonsignificant reduction in mortality has been observed in women treated with conjugated equine estrogens alone or combined with estrogen-progestin therapy. Where possible, transdermal routes of HT administration should be preferred as they have the least impact on coagulation. With combined treatment, natural progesterone should be favored as it is devoid of the antiapoptotic properties of other progestogens on breast cells. When beginning HT, low doses should be used and increased gradually until effective control of symptoms is achieved. Unless contraindications develop, patients may choose to continue HT as long as the benefits outweigh the risks. Regular reassessment of the woman's health status is mandatory. Women with premature menopause who begin HT before 50 years of age seem to have the most significant advantage in terms of longevity.

WIDER IMPLICATIONS

In women with bothersome menopausal symptoms, HT should be considered one of the mainstays of treatment. Clinical practitioners should tailor HT based on patient history, physical characteristics, and current health status so that benefits outweigh the risks.

Dietary inflammatory index and dietary energy density are associated with menopausal symptoms in postmenopausal women: a cross-sectional study

OBJECTIVES

No previous study has evaluated the association of the dietary inflammatory index (DII) and dietary energy density (DED) with menopausal symptoms and its subclasses in postmenopausal women. The aim of this study was to evaluate the association of DII score and DED with menopausal symptoms and its subtypes in Iranian postmenopausal women.

METHODS

This cross-sectional study was conducted on 393 postmenopausal women who attended health centers in the south of Tehran, Iran. The DII score was calculated using dietary factors obtained by a validated food frequency questionnaire. DED was defined as average daily energy intake (kcal) per gram of food. The Menopause Rating Scale questionnaire was used to evaluate the menopausal symptoms. The total Menopause Rating Scale score (TMRSS) was the sum of the somatic score (SS), psychological score (PS), and urogenital score. Linear regression analysis was used to assess the association of the DII score and DED with menopausal symptoms.

RESULTS

After adjusting for covariates, participants in the highest tertile of DII score had greater SS compared to those in the lowest tertile (βDIIt3vs1= 0.032, 95% confidence interval (CI): 0.004-0.068, P = 0.04). No significant relationship was found between DII score and PS, urogenital score or TMRSS. Furthermore, higher DED was associated with greater SS (βDIIt3vs1 = 0.071, 95% CI: 0.028-0.115, P = 0.001), PS (βDIIt3vs1 = 0.065, 95% CI: 0.012-0.121, P = 0.01) and TMRSS (βDIIt3vs1 = 0.053, 95% CI: 0.017-0.088, P = 0.004).

CONCLUSION

A proinflammatory diet was associated with higher menopause-specific somatic symptoms and higher DED was positively associated with menopausal symptoms.

Approach to Managing a Postmenopausal Patient

The case of a symptomatic, postmenopausal woman is presented and a full discussion of the approach to her management is discussed. Pertinent guidelines and scientific evidence are emphasized as support for the recommendations.

Use of hormone replacement therapy and risk of breast cancer: nested case-control studies using the QResearch and CPRD databases

OBJECTIVE

To assess the risks of breast cancer associated with different types and durations of hormone replacement therapy (HRT).

DESIGN

Two nested case-control studies.

SETTING

UK general practices contributing to QResearch or Clinical Practice Research Datalink (CPRD), linked to hospital, mortality, social deprivation, and cancer registry (QResearch only) data.

PARTICIPANTS

98 611 women aged 50-79 with a primary diagnosis of breast cancer between 1998 and 2018, matched by age, general practice, and index date to 457 498 female controls.

MAIN OUTCOME MEASURES

Breast cancer diagnosis from general practice, mortality, hospital, or cancer registry records. Odds ratios for HRT types, adjusted for personal characteristics, smoking status, alcohol consumption, comorbidities, family history, and other prescribed drugs. Separate results from QResearch or CPRD were combined.

RESULTS

Overall, 33 703 (34%) women with a diagnosis of breast cancer and 134 391 (31%) controls had used HRT prior to one year before the index date. Compared with never use, in recent users (<5 years) with long term use (≥5 years), oestrogen only therapy and combined oestrogen and progestogen therapy were both associated with increased risks of breast cancer (adjusted odds ratio 1.15 (95% confidence interval 1.09 to 1.21) and 1.79 (1.73 to 1.85), respectively). For combined progestogens, the increased risk was highest for norethisterone (1.88, 1.79 to 1.99) and lowest for dydrogesterone (1.24, 1.03 to 1.48). Past long term use of oestrogen only therapy and past short term (<5 years) use of oestrogen-progestogen were not associated with increased risk. The risk associated with past long term oestrogen-progestogen use, however, remained increased (1.16, 1.11 to 1.21). In recent oestrogen only users, between three (in younger women) and eight (in older women) extra cases per 10 000 women years would be expected, and in oestrogen-progestogen users between nine and 36 extra cases per 10 000 women years. For past oestrogen-progestogen users, the results would suggest between two and eight extra cases per 10 000 women years.

CONCLUSION

This study has produced new generalisable estimates of the increased risks of breast cancer associated with use of different hormone replacement preparations in the UK. The levels of risks varied between types of HRT, with higher risks for combined treatments and for longer duration of use.

Underlying Breast Cancer Risk and Menopausal Hormone Therapy

The recent Collaborative Group on Hormonal Factors in Breast Cancer (CGHFBC) publication calculated the attributable risk of breast cancer from use of estrogen alone and estrogen plus a synthetic progestogen for less than 5 to 15 or more years of use. This CGHFB report calculated attributable risk based on their findings of relative risk from pooled data from 58 studies. Notably, neither the CGHFBC nor other previous studies have examined the effect of underlying risk of breast cancer on attributable risk. This omission prompted us to determine the magnitude of the effect of underlying risk on attributable risk in this perspective. Meaningful communication of the potential risk of menopausal hormonal therapy requires providing women with the estimated risk above their existing underlying risk (ie, attributable risk). Therefore, we have estimated attributable risks from the data published by the CGHFBC, taking into account varying degrees of underlying risk. Based on the Endocrine Society Guideline on Menopausal Hormone Therapy (MHT), we divided groups into 3 categories of risk: low (1.5%), intermediate (3.0%), and high (6.0%) underlying risk of breast cancer over 5 years. In women taking estrogen plus a synthetic progestogen for 5 to 9 years, the attributable risks of MHT increased from 12, to 42, to 85 additional women per 1000 in the low-, intermediate-, and high-risk groups, respectively. The attributable risks for estrogen alone were lower but also increased based on underlying risk. Notably, the attributable risks were amplified with duration of MHT use, which increased both relative risk and breast cancer incidence.

Hormonal contraception and breast cancer

The recent Danish cohort study reported a 20% increased risk of breast cancer among current and recent hormonal contraception users. These results are largely consistent with previous studies. This study did not report on stage of disease at diagnosis, and it is not clear to what extent the apparent increased risk may be due to a small advance in the timing of diagnosis. This study did not report on the risk associated with the use of a 20-mcg ethinyl estradiol pill. They did find an increasing risk in current users of longer duration and an increased risk with use of the levonorgestrel intrauterine system-both of these potentially important findings have not been consistently found in previous studies and require further investigation. The breast cancer effects described now in multiple studies wane with time, and in the long term, hormonal contraception use has been found not to be associated with any increased total cancer risk.

Postmenopausal hormone use and cutaneous melanoma risk: A French prospective cohort study

Cutaneous melanoma has been suspected to be influenced by female hormones. Several studies reported a positive association between menopausal hormone therapy (MHT) use and melanoma risk; however, previous findings were conflicting. We sought to explore the associations between MHT use and melanoma risk in a prospective cohort of women in France, where a particularly wide variety of MHT formulations are available. E3N is a prospective cohort of 98,995 French women aged 40-65 years in 1990. MHT use was assessed through biennial self-administered questionnaires. We used Cox proportional hazards regression models adjusted for age and skin cancer risk factors. Over 1990-2008, 444 melanoma cases were ascertained among 75,523 postmenopausal women. Ever use of MHT was associated with a higher melanoma risk (hazard ratio (HR) = 1.35, 95% confidence intervals (CI) = 1.07-1.71). The association was strongest among past users (HR = 1.55, CI = 1.17-2.07, homogeneity for past vs. recent use: p = 0.11), and users of MHT containing norpregnane derivatives (HR = 1.59, CI = 1.11-2.27), although with no heterogeneity across types of MHT (p = 0.13). Among MHT users, the association was similar across durations of use. However, a higher risk was observed when treatment onset occurred shortly after menopause (<6 months: HR = 1.55, CI = 1.16-2.07 vs. ≥2 years). Associations between MHT use and melanoma risk were similar after adjustment for UV exposure, although MHT users were more likely to report sunscreen use than nonusers. Our data do not support a strong association between MHT use and melanoma risk. Further investigation is needed to explore potential effect modification by UV exposure on this relationship.

Clinical trials in menopause

OBJECTIVE

Clinical trials in menopause have undergone much scrutiny over the years. This has led to significant shifts in the treatment of symptomatic menopause and a substantial impact on women. We aim to delineate the key studies contributing to this controversy and highlight new directions specifically related to menopausal hormone therapy (HT) and vascular disease risk.

METHODS

We performed a search of sentinel studies delineating the risks and benefits of HT in otherwise healthy postmenopausal women. Using PubMed we input the following search terms: hormone replacement therapy, cardiovascular disease, coronary artery disease, coronary atherosclerosis, myocardial infarction, angina, coronary heart calcification, carotid intimal thickness, lipids, and/or lipoproteins. We included studies of menopausal women (surgical or natural) using combined estrogen/progestogen therapy or estrogen-only therapy that looked at cardiovascular disease risk factors or outcomes. Studies were evaluated for inclusion by the authors; however, this is not intended to be a systematic or an exhaustive analysis.

RESULTS

In women close to the time of menopause, there is a decreased risk of subclinical and clinical coronary heart disease with menopausal HT. Additionally, HT confers a significant benefit to vasomotor symptoms of menopause, bone health, and colorectal cancer. There is an increased risk of venous thromboembolism with oral formulations that appears mitigated with transdermal estradiol. Mixed data regarding breast cancer risk are available, with some studies suggesting an increased risk of invasive breast cancer with estrogen/progestogen therapy and a null effect with estrogen-only therapy. Other more long-term epidemiologic studies identify a decreased risk.

CONCLUSIONS

The available literature suggests that HT is a viable option for the primary prevention of cardiovascular disease in postmenopausal women. Newer trials will likely verify this assessment. If this is enough to change clinical practice, however, remains to be seen given the general fear of HT by many with prescriptive authority, and also the women in our care.

Estrogen metabolism in menopausal hormone users in the women's health initiative observational study: Does it differ between estrogen plus progestin and estrogen alone?

The WHI found an unexpected reduced breast cancer risk in women using CEE alone. We hypothesized CEE alone induces estrogen hydroxylation along the 2-pathway rather than the competing 16-pathway, a pattern linked to reduced postmenopausal breast cancer risk. One thousand eight hundred and sixty-four women in a WHIOS case-control study of estrogen metabolism and ovarian and endometrial cancer were studied of whom 609 were current E + P users (351 used CEE + MPA), while 272 used E alone (162 used CEE). Fifteen EM were measured, and analyses were conducted for each metabolite, hydroxylation pathway (2-, 4-, or 16-pathway) and ratios of pathway concentrations using inverse probability weighted linear regression. Compared to E + P users, all EM were higher in E alone users (significant for unconjugated estrone, total/conjugated estradiol, total/unconjugated 2-methoxyestrone, 4-methoxyestrone and unconjugated estriol). The relative concentrations of 2- and 4-pathway EM did not differ between the MHT users (2-pathway EM comprised 15% and 4-pathway EM <2% of the total), but 16-pathway EM were lower in E alone users (p = 0.036). Ratios of 2- and 4-pathway EM compared to 16-pathway EM were significantly higher in E alone compared to E + P users. Similar but not significant patterns were observed in CEE-alone and CEE + MPA users. Our data suggest that compared to E + P users, women using E alone have more extensive metabolism via the 2- vs. the competing 16-pathway. This is consistent with epidemiologic evidence of reduced postmenopausal breast cancer risk associated with this metabolic profile and may provide a clue to the breast cancer risk reduction in CEE alone users during the WHI.

Menopausal hormone therapy and breast cancer: what is the evidence from randomized trials?

The relationship between menopausal hormone therapy (HT) and breast cancer is complex and further complicated by misinformation, perception, and overgeneralization of data. These issues are addressed in this mini-review through the lens of the Women's Health Initiative (WHI) that has colored the view of HT and breast cancer. In the WHI, unopposed conjugated equine estrogen (CEE) reduced breast cancer risk and mortality. In the WHI CEE plus continuously combined medroxyprogesterone acetate (MPA) trial, although the hazard ratio (HR) was elevated it was statistically non-significant for an association between CEE + MPA and breast cancer. In fact, the increased HR was not due to an increased breast cancer incidence rate in women randomized to CEE + MPA therapy but rather due to a decreased and unexpectedly low breast cancer rate in the subgroup of women with prior HT use randomized to placebo. For women who were HT naïve when randomized to the WHI, the breast cancer incidence rate was not affected by CEE + MPA therapy relative to placebo for up to 11 years of follow-up. The current state of science indicates that HT may or may not cause breast cancer but the totality of data neither establish nor refute this possibility. Further, any association that may exist between HT and breast cancer appears to be rare and no greater than other medications commonly used in clinical medicine.

Hormonal contraception and breast cancer

The recent Danish cohort study reported a 20% increased risk of breast cancer among current and recent hormonal contraception users. These results are largely consistent with previous studies. This study did not report on stage of disease at diagnosis and it is not clear to what extent the apparent increased risk may be due to a small advance in the timing of diagnosis. This study did not report on the risk associated with the use of a 20-μg ethinyl estradiol pill. They did find an increasing risk in current users of longer duration and an increased risk with use of the levonorgestrel intrauterine system-both of these potentially important findings have not been consistently found in previous studies and require further investigation. The breast cancer effects described now in multiple studies wane with time, and in the long-term hormonal contraception use has been found not to be associated with any increased total cancer risk.

Doxorubicin-induced cardiotoxicity is suppressed by estrous-staged treatment and exogenous 17β-estradiol in female tumor-bearing spontaneously hypertensive rats

Background

Doxorubicin (DOX), an anthracycline therapeutic, is widely used to treat a variety of cancer types and known to induce cardiomyopathy in a time and dose-dependent manner. Postmenopausal and hypertensive females are two high-risk groups for developing adverse effects following DOX treatment. This may suggest that endogenous reproductive hormones can in part suppress DOX-induced cardiotoxicity. Here, we investigated if the endogenous fluctuations in 17β-estradiol (E2) and progesterone (P4) can in part suppress DOX-induced cardiomyopathy in SST-2 tumor-bearing spontaneously hypersensitive rats (SHRs) and evaluate if exogenous administration of E2 and P4 can suppress DOX-induced cardiotoxicity in tumor-bearing ovariectomized SHRs (ovaSHRs).

Methods

Vaginal cytology was performed on all animals to identify the stage of the estrous cycle. Estrous-staged SHRs received a single injection of saline, DOX, dexrazoxane (DRZ), or DOX combined with DRZ. OvaSHRs were implanted with time-releasing pellets that contained a carrier matrix (control), E2, P4, Tamoxifen (Tam), and combinations of E2 with P4 and Tam. Hormone pellet-implanted ovaSHRs received a single injection of saline or DOX. Cardiac troponin I (cTnI), E2, and P4 serum concentrations were measured before and after treatment in all animals. Cardiac damage and function were further assessed by echocardiography and histopathology. Weight, tumor size, and uterine width were measured for all animals.

Results

In SHRs, estrous-staged DOX treatment altered acute estrous cycling that ultimately resulted in prolonged diestrus. Twelve days after DOX administration, all SHRs had comparable endogenous circulating E2. Thirteen days after DOX treatment, SHRs treated during proestrus had decreased cardiac output and increased cTnI as compared to animals treated during estrus and diestrus. DOX-induced tumor reduction was not affected by estrous-staged treatments. In ovaSHRs, exogenous administration of E2 suppressed DOX-induced cardiotoxicity, while P4-implanted ovaSHRs were partly resistant. However, ovaSHRs treated with E2 and P4 did not have cardioprotection against DOX-induced damage.

Conclusions

This study demonstrates that estrous-staged treatments can alter the extent of cardiac damage caused by DOX in female SHRs. The study also supports that exogenous E2 can suppress DOX-induced myocardial damage in ovaSHRs.

Electronic supplementary material

The online version of this article (10.1186/s13293-018-0183-9) contains supplementary material, which is available to authorized users.

Evaluating different breast tumor progression models using screening data

Background

Mammography screening is used to detect breast cancer at an early treatable stage, reducing breast cancer mortality. Traditionally, breast cancer has been seen as a disease with only progressive lesions, and here we examine the validity of this assumption by testing if incidence levels after introducing mammography screening can be reproduced assuming only progressive tumors.

Methods

Breast cancer incidence data 1990–2009 obtained from the initially screened Norwegian counties (Akershus, Oslo, Rogaland and Hordaland) was included, covering the time-period before, during and after the introduction of mammography screening. From 1996 women aged 50–69 were invited for biennial public screening. Using estimates of tumor growth and screening sensitivity based on pre-screening and prevalence screening data (1990–1998), we simulated incidence levels during the following period (1999–2009).

Results

The simulated incidence levels during the period with repeated screenings were markedly below the observed levels. The results were robust to changes in model parameters. Adjusting for hormone replacement therapy use, we obtained levels closer to the observed levels. However, there was still a marked gap, and only by assuming some tumors that undergo regressive changes or enter a markedly less detectable state, was our model able to reproduce the observed incidence levels.

Conclusions

Models with strictly progressive tumors are only able to partly explain the changes in incidence levels observed after screening introduction in the initially screened Norwegian counties. More complex explanations than a time shift in detection of future clinical cancers seem to be needed to reproduce the incidence trends, questioning the basis for many over-diagnosis calculations. As data are not randomized, similar studies in other populations are wanted to exclude effect of unknown confounders.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4130-2) contains supplementary material, which is available to authorized users.

Change in risk of breast cancer after receiving hormone replacement therapy by considering effect-modifiers: a systematic review and dose-response meta-analysis of prospective studies

We synthesize the current literatures and use the power of meta-analysis to examine trends on association between hormone replacement therapy (HRT) and the risk of breast cancer (BC). We performed a comprehensive literature search using PubMed, EMBASE, and Web of Science from their inception until Jan 2017. Prospective studies that provided adjusted risk estimates of HRT and BC risk were eligible. Categorical and dose-response meta-analyses followed the PRISMA were conducted using random effects model and restricted cubic spline model, respectively. Forty-seven publications from thirty-five unique studies were included, involving 3,898,376 of participants and 87,845 of BC cases. Compared with non-users, RR for current estrogen-only therapy (ET) users was 1.14 (95% confidence interval (CI) = 1.05–1.22), and for per year increases was 1.02 (95% CI = 1.02–1.02). Moreover, RR for current estrogen plus progestin therapy (EPT) users was 1.76, (95% CI = 1.56–1.96), and for per year increases was 1.08 (95% CI = 1.08–1.08). Dose-response analyses revealed 8–10 years’ onset peaks, and indicated residual increased BC risk remained after stopping use of ET regimen rather than for EPT. Effect-modifiers like BMI, duration of use, race/ethnicity, routes of administration were recognized. In Conclusions, current use of EP or EPT and ever use of tibolone are associated with an elevated risk of BC. Compared with slim HRT users and non-users, lower BC risks were found among overweight/obese HRT users and former EPT users, respectively. Both ET and EPT users are associated with higher risk of lobular BC than ductal BC, and more ER-positive than negative BC cases were detected among EPT users.

Menopausal hormone therapy and breast cancer: what is the true size of the increased risk?

BACKGROUND

Menopausal hormone therapy (MHT) increases breast cancer risk; however, most cohort studies omit MHT use after enrolment and many infer menopausal age.

METHODS

We used information from serial questionnaires from the UK Generations Study cohort to estimate hazard ratios (HRs) for breast cancer among post-menopausal women with known menopausal age, and examined biases induced when not updating data on MHT use and including women with inferred menopausal age.

RESULTS

Among women recruited in 2003-2009, at 6 years of follow-up, 58 148 had reached menopause and 96% had completed a follow-up questionnaire. Among 39 183 women with known menopausal age, 775 developed breast cancer, and the HR in relation to current oestrogen plus progestogen MHT use (based on 52 current oestrogen plus progestogen MHT users in breast cancer cases) relative to those with no previous MHT use was 2.74 (95% confidence interval (CI): 2.05-3.65) for a median duration of 5.4 years of current use, reaching 3.27 (95% CI: 1.53-6.99) at 15+ years of use. The excess HR was underestimated by 53% if oestrogen plus progestogen MHT use was not updated after recruitment, 13% if women with uncertain menopausal age were included, and 59% if both applied. The HR for oestrogen-only MHT was not increased (HR=1.00; 95% CI: 0.66-1.54).

CONCLUSIONS

Lack of updating MHT status through follow-up and inclusion of women with inferred menopausal age is likely to result in substantial underestimation of the excess relative risks for oestrogen plus progestogen MHT use in studies with long follow-up, limited updating of exposures, and changing or short durations of use.

The modulation of estrogen-induced apoptosis as an interpretation of the women's health initiative trials

The Women's Health Initiative (WHI) consisted of two placebo controlled trials: one in women with a uterus, using conjugated equine estrogen (CEE) plus medroxyprogesterone acetate (MPA) and the second trial in women without a uterus used CEE alone. The study population average age was approximately 63 years. Although the predicted rise in breast cancer occurred in the MPA plus CEE trial, the CEE alone trial, had a sustained decrease in breast cancer incidence. A unifying theory is presented that explains the decrease in breast cancer based on the new biology of estrogen-induced apoptosis in long-term estrogen deprived nascent breast cancer cells. Glucocorticoids block estrogen-induced apoptosis and MPA has glucocorticoid activity. This is why MPA increases breast cancer when used with CEE as menopausal hormone replacement. A safer menopausal hormone therapy can now be designed with a more selective synthetic progestin such as norethindrone acetate.

Embedding clinical interventions into observational studies

Novel approaches to observational studies and clinical trials could improve the cost-effectiveness and speed of translation of research. Hybrid designs that combine elements of clinical trials with observational registries or cohort studies should be considered as part of a long-term strategy to transform clinical trials and epidemiology, adapting to the opportunities of big data and the challenges of constrained budgets. Important considerations include study aims, timing, breadth and depth of the existing infrastructure that can be leveraged, participant burden, likely participation rate and available sample size in the cohort, required sample size for the trial, and investigator expertise. Community engagement and stakeholder (including study participants) support are essential for these efforts to succeed.

European Code against Cancer 4th Edition: Medical exposures, including hormone therapy, and cancer

The 4th edition of the European Code against Cancer recommends limiting - or avoiding when possible - the use of hormone replacement therapy (HRT) because of the increased risk of cancer, nevertheless acknowledging that prescription of HRT may be indicated under certain medical conditions. Current evidence shows that HRT, generally prescribed as menopausal hormone therapy, is associated with an increased risk of cancers of the breast, endometrium, and ovary, with the risk pattern depending on factors such as the type of therapy (oestrogen-only or combined oestrogen-progestogen), duration of treatment, and initiation according to the time of menopause. Carcinogenicity has also been established for anti-neoplastic agents used in cancer therapy, immunosuppressants, oestrogen-progestogen contraceptives, and tamoxifen. Medical use of ionising radiation, an established carcinogen, can provide major health benefits; however, prudent practices need to be in place, with procedures and techniques providing the needed diagnostic information or therapeutic gain with the lowest possible radiation exposure. For pharmaceutical drugs and medical radiation exposure with convincing evidence on their carcinogenicity, health benefits have to be balanced against the risks; potential increases in long-term cancer risk should be considered in the context of the often substantial and immediate health benefits from diagnosis and/or treatment. Thus, apart from HRT, no general recommendations on reducing cancer risk were given for carcinogenic drugs and medical radiation in the 4th edition of European Code against Cancer. It is crucial that the application of these measures relies on medical expertise and thorough benefit-risk evaluation. This also pertains to cancer-preventive drugs, and self-medication with aspirin or other potential chemopreventive drugs is strongly discouraged because of the possibility of serious, potentially lethal, adverse events.

Point: incident exposures, prevalent exposures, and causal inference: does limiting studies to persons who are followed from first exposure onward damage epidemiology?

The idea that epidemiologic studies should start from first exposure onward has been advocated in the past few years. The study of incident exposures is contrasted with studies of prevalent exposures in which follow-up may commence after first exposure. The former approach is seen as a hallmark of a good study and necessary for causal inference. We argue that studying incident exposures may be necessary in some situations, but it is not always necessary and is not the preferred option in many instances. Conducting a study involves decisions as to which person-time experience should be included. Although studies of prevalent exposures involve left truncation (missingness on the left), studies of incident exposures may involve right censoring (missingness on the right) and therefore may not be able to assess the long-term effects of exposure. These considerations have consequences for studies of dynamic (open) populations that involve a mixture of prevalent and incident exposures. We argue that studies with prevalent exposures will remain a necessity for epidemiology. The purpose of this paper is to restore the balance between the emphasis on first exposure cohorts and the richness of epidemiologic information obtained when studying prevalent exposures.

A(nother) scientific strategy to prevent breast cancer in postmenopausal women by enhancing estrogen-induced apoptosis?

The innovation of combining bazedoxifene with conjugated estrogens provides a new opportunity for women's health. The finding by the Women's Health Initiative-that the administration of conjugated equine estrogens alone to women in their 60s who have had hysterectomy results in a decrease in breast cancer incidence and a drop in mortality--was unanticipated but can now be exploited for another gain in women's health. The issue to be considered is how postmenopausal women can improve their lifestyle to take advantage of conjugated equine estrogens-alone therapy. Food and Drug Administration approval of the combination of bazedoxifene and conjugated estrogens now provides an opportunity for postmenopausal women to reduce hot flashes and to potentially selectively sensitize occult breast cancer cells to the apoptotic actions of estrogen. Clinical trials are proposed to advance women's health and to reduce the incidence of breast cancer.

Benefits and risks during HRT: main safety issue breast cancer

To assess the benefits and risks during hormone replacement therapy (HRT) in postmenopausal women, the only placebo-controlled study testing clinical endpoints with high statistical power has been the Women's Health Initiative (WHI). Although this trial, conducted mainly in older high-risk women, might not reflect the practical conditions for the normal use of HRT, the WHI for the first time provides the main risks in relative as well as in absolute numbers, which are venous thromboembolism and breast cancer, and in older women also myocardial infarction and stroke. Proven benefits such as treatment of climacteric symptoms, reduction of osteoporotic fractures and decrease of colon cancer risk seem to be only important for younger women, because only with early start of HRT cardiovascular risks can be reduced. Reduction of cardiovascular risks can be achieved using transdermal HRT, which, however, was not tested in a placebo-controlled study design similar to that in the WHI. This review focuses on the results of the WHI, comparing different age groups, and in general especially on the main fear of women, risk of breast cancer, which has been defined as a special project between two universities, a close collaboration of a German and Chinese research group.

Bias in Observational Studies of the Association between Menopausal Hormone Therapy and Breast Cancer

Background

During the period 1985-2000 the breast cancer incidence rates increased 50% in the age group invited to mammography screening in Norway and Sweden. Simultaneously, use of hormone replacement treatment therapy (HT) increased 5 times. Several influential observational studies showed that HT was associated with 50% to 100% increased risk of breast cancer and most for those using combined (estrogen plus progestin) hormone replacement therapy (CHT). In contrast, the randomized WHI trial reported that CHT increased the risk by 10% for those not having previously used hormones and 24% when including previous users in the analyses. In another randomized trial, estrogen use only was not associated with any increased risk at all. After the WHI trial was published in 2003, use of HT dropped 70% within 5 years in Norway and Sweden while breast cancer rates were essentially unchanged. After 2008, HT use has dropped further and breast cancer incidence rates have started increasing again. The study objective is to calculate and to explain potential bias in the observational study design.

Methods and Findings

Here we use data from the randomized WHI trial and analyze these data as done in the observational studies to calculate the magnitude of the potential biases in the observational study design. Time varying effect of hormones and categorization of the follow-up time may increase the hazard ratio for long-term users from 1.10 to 1.48. Selective retrospective reporting of hormone use may further increase the hazard ratio to 1.68.

Conclusions

We suggest that the mechanism causing higher hazard ratio of breast cancer (compared to the observational studies) is the time-varying effect of CHT on the breast cancer risk and selective retrospective reporting of hormone use. Other risk factors for the increase in breast cancer risk in the age group 50-69 years should be considered, for example, overdiagnosis.

Menopausal hormone therapy and breast cancer mortality: clinical implications

The Women's Health Initiative (WHI) has conducted two randomized, placebo-controlled clinical trials to evaluate the influence of menopausal hormone therapy on chronic disease risk. Estrogen plus progestin was evaluated in 16,608 postmenopausal women without prior hysterectomy during 5.6 years' intervention. In that setting, combined hormone therapy use significantly increased breast cancer incidence and interfered with breast cancer detection. The breast cancers were not limited to estrogen receptor positive, favorable prognosis cancers and were identified at more advanced stage. As a result, deaths from breast cancer were significantly increased by estrogen plus progestin use. While the absolute breast cancer risk for relatively short term (2-4 years) use of combined hormone therapy is small, on a population basis a therapy which nearly doubles deaths from breast cancer requires cautious use. Estrogen alone was evaluated in 10,739 postmenopausal women with prior hysterectomy during 7.1 years' intervention. There was an overall reduction of breast cancer incidence seen with estrogen alone use and a suggestion that the effect on risk was more pronounced in women initiating hormone therapy further from menopause. Nonetheless, women with prior hysterectomy can be assured that short duration estrogen alone use for climacteric symptom management is relatively safe. Neither estrogen plus progestin nor estrogen alone should be used for chronic disease risk reduction. The safety of duration of use on chronic disease risk longer than in the WHI clinical trials is not defined.

Menopausal hormone therapy and cancer: changing clinical observations of target site specificity

Menopausal hormone therapy with estrogen plus progestin or estrogen alone (for women with prior hysterectomy) is still used by millions of women for climacteric symptom management throughout the world. Until 2002, hormone therapy influence on cancer risk and other chronic diseases was determined through observational study reports. Since then, results from the Women's Health Initiative randomized, placebo-controlled hormone therapy trials have substantially changed concepts regarding estrogen plus progestin and estrogen alone influence on the most common cancers in postmenopausal women. In these trials, estrogen plus progestin significantly increased breast cancer incidence and deaths from breast cancer, significantly increased deaths from lung cancer, significantly decreased endometrial cancer, and did not have a clinically significant influence on colorectal cancer. In contrast, estrogen alone use in women with prior hysterectomy significantly reduced breast cancer incidence and deaths from breast cancer without significant influence on colorectal cancer or lung cancer. These complex results are discussed in the context of known potential mediating mechanisms of action involved in interaction with steroid hormone receptors.

Postmenopausal hormone therapy and the risks of coronary heart disease, breast cancer, and stroke

The principal findings are briefly reviewed from the Women's Health Initiative trials of the most commonly used postmenopausal hormone regimens in the United States-conjugated equine estrogens and these same estrogens plus medroxyprogesterone acetate. A more detailed review is presented for three major clinical outcomes: coronary heart disease (CHD), the primary trial outcome for which a major benefit was hypothesized; invasive breast cancer, the primary safety outcome for which some adverse effect was expected; and stroke which surfaced as an important adverse effect with both regimens, and one that is influential in decisions concerning the continued use of postmenopausal estrogens alone. The review for these outcomes includes an update on interactions of treatment effects with study subject characteristics and exposures and with prerandomization biomarker levels. It also includes a focus on timing issues that are important to the understanding of treatment effects. Specifically, with combined estrogen plus progestin, CHD risk was elevated early with the elevation dissipating after a few years of treatment, whereas breast cancer elevations increased during the treatment period, and climbed to about a threefold increase following 5 years of adherence. Importantly, breast cancer risk elevations appear to be higher among women who initiate treatment at the menopause, or soon thereafter, compared with women having a longer gap time. Stroke effects, on the contrary, did not seem to vary appreciably with these timing issues. The adverse effect was evidently localized to ischemic strokes, for which there was an approximate 50% increase with either regimen. The rather limited knowledge concerning the biomarkers and biological pathways that mediate the hormone therapy effects on these diseases is also briefly reviewed.

Is breast cancer risk the same for all progestogens?

The population-based case–control study CECILE investigated the impact of various menopausal hormone therapy (MHT) products on breast cancer (BC) risk in 1,555 postmenopausal women [1]. The case group (n = 739) included incident cases of in situ (!) or invasive BC in postmenopausal women. The control group (n = 816) included women from the general population within predefined quotas by age and socio-economic status (SES). While quotas by age were applied to obtain similar distributions by age among controls and among cases, quotas by SES in control women were applied to reflect the distribution by SES of women in the general population in the study area. Data of participants were obtained by a structured questionnaire during in-person interviews, and from pathology reports if applicable, respectively. Women were divided into current and past MHT user. MHTs were classified in estrogen-only therapy (ET), estrogen combined with progestin therapy (EPT) and tibolone. EPT was subdivided in three subtypes according to the progestogen constituent: natural micronized progesterone, progesterone derivatives, and testosterone derivatives. In comparison to never MHT users, any current or past MHT use (ET, EPT, tibolone) was not associated with an increased BC risk. However, in subanalysis BC risk was significantly increased for current use of EPT for 4 or more years (n = 73 cases and n = 56 controls, adjusted OR 1.55; 95 % CI 1.02–2.36). Within the group of current EPT users for 4 or more years, 14 cases had used estrogens combined with micronized progesterone (n = 17 controls), and 55 a combination with a synthetic progestogen (n = 34 controls), respectively. Compared to never MHT use, current use of EPT containing a synthetic progestogen for 4 or more years was associated with a significantly increased BC risk (adjusted OR 2.07; 95 % CI 1.26–3.39), but EPT containing micronized progesterone was not (adjusted OR 0.79; 95 % CI 0.37–1.71). 73 % of current MHT users started treatment within the first year of onset of menopause. Early EPT (n = 52 cases and n = 38 controls, adjusted OR 1.65; 95 % CI 1.02–2.69), but not early ET, starters had a significantly higher BC risk compared to never MHT users. In contrast, MHT initiation beyond 1 year after menopause was not associated with an increased BC risk. The authors concluded that: (1) ET and EPT containing natural progesterone did not increase BC risk whereas, (2) BC risk was increased in users of tibolone or EPT containing a synthetic progestogen, respectively, and that (3) MHT use early after onset of menopause was associated with an increased BC risk as compared to women who delay MHT beyond 1 or more years.

Menopausal hormone therapy and breast cancer

Observational and randomized controlled trial data have extensively examined the relationship between menopausal hormone therapy (MHT) and risk of developing breast cancer. A highly influential study from the Women's Health Initiative (WHI) in 2002 reported that a MHT regimen of conjugated equine estrogens and medroxyprogesterone acetate increased the risk of breast cancer by 26%. Later reports from the WHI indicated that a MHT regimen with conjugated equine estrogens alone decreased the risk of breast cancer by 23%. Critical re-examination of the WHI study noted that the average participant age was 63, that few women had symptoms, and that the WHI results might not apply to younger, symptomatic women shortly after menopause. Since the original publications, several post hoc analyses and observational studies have stimulated reconsideration of the WHI findings. Emphasis has been directed toward risks in younger women just entering the menopause, the subgroup who are most likely to be considering MHT use. The goal of this treatise is to integrate available mechanistic and clinical information related to the use of estrogen alone or estrogen plus a progestogen for five years or less. These data suggest that estrogen alone neither decreases nor increases risk in younger women initiating therapy close to the time of menopause but decreases risk in older women. Both younger and older women experience an excess risk with estrogen plus a progestogen. The attributable risk in younger women is less in those with a low underlying Gail Model risk score. Effects of MHT on risk largely reflect actions on pre-existing, occult, undiagnosed breast cancers. Tumor kinetic models suggest that the pro-proliferative effects of estrogen plus a progestogen on occult tumors provide a mechanistic explanation for the increased risk with this therapy. Pro-apoptotic effects of estrogen alone may explain the reduction of breast cancer in women starting this therapy at an average age of 63 as reported in the WHI study. This article is part of a Special Issue entitled 'Menopause'.

High expression of lncRNA MALAT1 suggests a biomarker of poor prognosis in colorectal cancer

Introduction

Paradoxically, a breast cancer risk reduction with conjugated equine estrogens (CEE) and a risk elevation with CEE plus medroxyprogesterone acetate (CEE + MPA) were observed in the Women’s Health Initiative (WHI) randomized controlled trials. The effects of hormone therapy on serum sex hormone levels, and on the association between baseline sex hormones and disease risk, may help explain these divergent breast cancer findings.

Methods

Serum sex hormone concentrations were measured for 348 breast cancer cases in the CEE + MPA trial and for 235 cases in the CEE trial along with corresponding pair-matched controls, nested within the WHI trials of healthy postmenopausal women. Association and mediation analyses, to examine the extent to which sex hormone levels and changes can explain the breast cancer findings, were conducted using logistic regression.

Results

Following CEE treatment, breast cancer risk was associated with higher concentrations of baseline serum estrogens, and with lower concentrations of sex hormone binding globulin. However, following CEE + MPA, there was no association of breast cancer risk with baseline sex hormone levels. The sex hormone changes from baseline to year 1 provided an explanation for much of the reduced breast cancer risk with CEE. Specifically, the treatment odds ratio (95% confidence interval) increased from 0.71 (0.43, 1.15) to 0.92 (0.41, 2.09) when the year 1 measures were included in the logistic regression analysis. In comparison, the CEE + MPA odds ratio was essentially unchanged when these year 1 measures were included.

Conclusions

Breast cancer risk remains low following CEE use among women having favorable baseline sex hormone profiles, but CEE + MPA evidently produces a breast cancer risk for all women similar to that for women having an unfavorable baseline sex hormone profile. These patterns could reflect breast ductal epithelial cell stimulation by CEE + MPA that is substantially avoided with CEE, in conjunction with relatively more favorable effects of either regimen following a sustained period of estrogen deprivation. These findings may have implications for other hormone therapy formulations and routes of delivery.

Trial registration

clinicaltrials.gov identifier: NCT00000611.

The history of hormone therapy use and recent controversy related to heart disease and breast cancer arising from prevention trial outcomes

The reasons for hormone therapy use have changed dramatically over time from being very popular for the purpose of preserving youth in women to menopause-related symptom management, disease prevention, and now back to menopause-related symptom management. Over time, several important risks associated with the use of hormone therapy have become evident, causing dramatic reductions in the use of hormone therapy for periods of time following identification of these risks. Most recently, randomized controlled prevention trials that evaluated hormone therapy for the purpose of reducing or preventing coronary heart disease among women have found that hormone therapy is associated with increased rather than decreased risks for coronary heart disease. The most recent of these trials again identified increased risks for breast cancer associated with estrogen plus progestogen therapy. The evolving evidence base from these randomized controlled prevention trials is complicated and in some cases contradictory. Specifically, the data suggest that the timing of when hormone therapy is initiated once a woman is postmenopausal may influence her risk for developing heart disease and breast cancer. In this article, contradictory evidence is carefully sifted so risks and benefits can be weighed by clinicians when partnering with women to individualize decisions about using hormone therapy.

Risk of breast cancer by type of menopausal hormone therapy: a case-control study among post-menopausal women in France

Background

There is extensive epidemiological evidence that menopausal hormone therapy (MHT) increases breast cancer risk, particularly combinations of estrogen and progestagen (EP). We investigated the effects of the specific formulations and types of therapies used by French women. Progestagen constituents, regimen (continuous or sequential treatment by the progestagen), and time interval between onset of menopause and start of MHT were examined.

Methods

We conducted a population-based case-control study in France in 1555 menopausal women (739 cases and 816 controls). Detailed information on MHT use was obtained during in-person interviews. Odds ratios and 95% confidence interval adjusted for breast cancer risk factors were calculated.

Results

We found that breast cancer risk differed by type of progestagen among current users of EP therapies. No increased risk was apparent among EP therapy users treated with natural micronized progesterone. Among users of EP therapy containing a synthetic progestin, the odds ratio was 1.57 (0.99-2.49) for progesterone-derived and 3.35 (1.07-10.4) for testosterone-derived progestagen. Women with continuous regimen were at greater risk than women treated sequentially, but regimen and type of progestagen could not be investigated independently, as almost all EP combinations containing a testosterone-derivative were administered continuously and vice-versa. Tibolone was also associated with an increased risk of breast cancer. Early users of MHT after onset of menopause were at greater risk than users who delayed treatment.

Conclusion

This study confirms differential effects on breast cancer risk of progestagens and regimens specifically used in France. Formulation of EP therapies containing natural progesterone, frequently prescribed in France, was not associated with increased risk of breast cancer but may poorly protect against endometrial cancer.

Where are we 10 years after the Women's Health Initiative?

The media attention surrounding the publication of the initial results of WHI in 2002 led to fear and confusion regarding the use of hormonal therapy (HT) after menopause. This led to a dramatic reduction in prescriptions for HT in the United States and around the world. Although in 2002 it was stated that the results pertained to all women receiving HT, subsequent studies from the Women's Health Initiative (WHI) and others clearly showed that younger women and those close to menopause had a very beneficial risk-to-benefit ratio. Indeed, the results showed similar protective effects for coronary disease and a reduction in mortality that had been shown in earlier observational studies, which had also focused on younger symptomatic women. In younger women, the increased number of cases of venous thrombosis and ischemic stroke was low, rendering them "rare" events using World Health Organization nomenclature. Breast cancer rates were also low and were found to be decreased with estrogen alone. In women receiving estrogen and progestogen for the first time in the WHI, breast cancer rates did not increase significantly for 7 years. Other data suggest that other regimens and the use of other progestogens may also be safer. It has been argued that in the 10 years since WHI, many women have been denied HT, including those with severe symptoms, and that this has significantly disadvantaged a generation of women. Some reports have also suggested an increased rate of osteoporotic fractures since the WHI. Therefore, the question is posed as to whether we have now come full circle in our understanding of the use of HT in younger women. Although it is appropriate to treat women with symptoms at the onset of menopause, because there is no proven therapy for primary prevention, in some women the use of HT for this role may at least be entertained.

Postmenopausal hormone therapy: risks and benefits

Postmenopausal hormone therapy (PMHT) is used for the relief of menopausal symptoms, but the dosage has varied greatly throughout its existence. By the end of the 1990s, PMHT was mainly used to prevent chronic diseases such as osteoporosis, coronary heart disease and dementia, and large prevention trials were undertaken in this context. Following the initial negative reports of these trials, use of PMHT dramatically decreased. These reports noted surprisingly increased risks, notably of coronary heart disease, stroke and breast cancer, in people who used PMHT. Nowadays, considering the currently available data, it seems that an important distinction should be made between the treatment of climacteric symptoms in young, generally healthy, postmenopausal women and the prevention of chronic diseases in elderly women. PMHT seems to be beneficial and safe for postmenopausal symptomatic women aged <60 years. Treatments with a high safety profile should be the preferred option, including low-dose PMHT, oestrogen-only therapy in women who have had a hysterectomy, and vaginal oestrogen therapy for women with atrophic vaginitis. Nonandrogenic progestin might have a reduced thrombotic and breast cancer risk, and transdermal oestrogen could have a reduced thrombotic risk. Nevertheless, PMHT should not be used for the prevention of chronic diseases in the elderly (>70 years old) owing to the increased risk of stroke and breast cancer in these patients.

Estrogen plus progestin and breast cancer incidence and mortality in the Women's Health Initiative Observational Study

BACKGROUND

In the Women's Health Initiative (WHI) randomized trial, estrogen plus progestin increased both breast cancer incidence and mortality. In contrast, most observational studies associate estrogen plus progestin with favorable prognosis breast cancers. To address differences, a cohort of WHI observational study participants with characteristics similar to the WHI clinical trial was studied.

METHODS

We identified 41 449 postmenopausal women with no prior hysterectomy and mammogram negative within 2 years who were either not hormone users (n = 25 328) or estrogen and progestin users (n = 16 121). Multivariable-adjusted Cox proportional hazard regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CI). All statistical tests were two-sided.

RESULTS

After a mean of 11.3 (SD = 3.1) years, with 2236 breast cancers, incidence was higher in estrogen plus progestin users than in nonusers (0.60% vs 0.42%, annualized rate, respectively; HR = 1.55, 95% CI = 1.41 to 1.70, P < .001). Women initiating hormone therapy closer to menopause had higher breast cancer risk with linear diminishing influence as time from menopause increased (P < .001). Survival after breast cancer, measured from diagnosis, was similar in combined hormone therapy users and nonusers (HR = 1.03, 95% CI = 0.79 to 1.35). On a population basis, there were somewhat more deaths from breast cancer, measured from cohort entry (HR = 1.32, 95% CI = 0.90 to 1.93, P = .15), and more all-cause deaths after breast cancer (HR = 1.65, 95% CI = 1.29 to 2.12, P < .001) in estrogen plus progestin users than in nonusers.

CONCLUSIONS

Consistent with WHI randomized trial findings, estrogen plus progestin use is associated with increased breast cancer incidence. Because prognosis after diagnosis on combined hormone therapy is similar to that of nonusers, increased breast cancer mortality can be expected.

Health risks and benefits from calcium and vitamin D supplementation: Women's Health Initiative clinical trial and cohort study

SUMMARY

The Women's Health Initiative (WHI) double-blind, placebo-controlled clinical trial randomly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D(3) daily or placebo, with average intervention period of 7.0 years. The trial was designed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture, and secondarily, total fracture and colorectal cancer.

INTRODUCTION

This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data, with emphasis on fractures, cardiovascular disease, cancer, and total mortality.

METHODS

WHI calcium and vitamin D randomized clinical trial (CT) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation, and these data were contrasted and combined with corresponding data from the WHI prospective observational study (OS).

RESULTS

Among women not taking personal calcium or vitamin D supplements at baseline, the hazard ratio [HR] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 (95 % confidence interval (CI), 0.38-1.00). In combined analyses of CT and OS data, the corresponding HR was 0.65 (95 % CI, 0.44-0.98). Supplementation effects were not apparent on the risks of myocardial infarction, coronary heart disease, total heart disease, stroke, overall cardiovascular disease, colorectal cancer, or total mortality, while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive.

CONCLUSION

Though based primarily on a subset analysis, long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women. Other health benefits and risks of supplementation at doses considered, including an elevation in urinary tract stone formation, appear to be modest and approximately balanced.

Effects of menopausal hormone therapy on ductal carcinoma in situ of the breast

Post-menopausal hormone therapy with estrogen plus progestin is consistently reported to be associated with an increased risk of invasive breast cancer. However, findings on an association between hormone use and ductal carcinoma in situ of the breast (DCIS), a possible precursor lesion of invasive breast cancer, are sparse and inconsistent. Women's Health Initiative data were used to assess the effects of hormone therapy on the risk of DCIS in two clinical trials of hormone therapy (16,276 women enrolled in the trial of daily conjugated equine estrogens plus medroxyprogesterone acetate (CEE + MPA) vs placebo; 10,187 women enrolled in the trial of CEE-alone vs placebo). The effects of hormone therapy on DCIS in clinical trial participants were assessed during the intervention, post-intervention, and entire followup periods, and in the observational study (OS; 30,421 CEE + MPA users and non-users and 18,657 CEE-alone users and non-users who met eligibility criteria similar to the clinical trial). Compared to placebo, CEE + MPA was non-significantly associated with higher risk of DCIS over approximate average of 11 years of follow-up (HR = 1.23; 95 % CI: 0.91-1.64). No statistical difference was detected between intervention and post-intervention phases (p = 0.32). Corresponding OS results supported an increased risk for DCIS in CEE + MPA users compared to women who were non-users (HR = 1.65; 95 % CI: 1.25-2.19) after adjusting for potential confounders. There was no clear association between CEE-alone use and risk of DCIS. CEE-alone trial data showed that the risk of DCIS was non-significantly lower in the treatment than in the placebo group, while analysis of the corresponding OS showed a non-significantly higher risk of DCIS in the CEE-alone users than non-users. Our analysis suggests that combined estrogen plus progestin use in post-menopausal women may increase risk of DCIS. Whether estrogen-alone use is associated with DCIS requires further investigation.

Percutaneous estradiol/oral micronized progesterone has less-adverse effects and different gene regulations than oral conjugated equine estrogens/medroxyprogesterone acetate in the breasts of healthy women in vivo

Gene expression analysis of healthy postmenopausal women in a prospective clinical study indicated that genes encoding for epithelial proliferation markers Ki-67 and progesterone receptor B mRNA are differentially expressed in women using hormone therapy (HT) with natural versus synthetic estrogens. Two 28-day cycles of daily estradiol (E2) gel 1.5 mg and oral micronized progesterone (P) 200 mg/day for the last 14 days of each cycle did not significantly increase breast epithelial proliferation (Ki-67 MIB-1 positive cells) at the cell level nor at the mRNA level (MKI-67 gene). A borderline significant beneficial reduction in anti-apoptotic protein bcl-2, favouring apoptosis, was also seen followed by a slight numeric decrease of its mRNA. By contrast, two 28-day cycles of daily oral conjugated equine estrogens (CEE) 0.625 mg and oral medroxyprogesterone acetate (MPA) 5 mg for the last 14 days of each cycle significantly increased proliferation at both the cell level and at the mRNA level, and significantly enhanced mammographic breast density, an important risk factor for breast cancer. In addition, CEE/MPA affected around 2,500 genes compared with just 600 affected by E2/P. These results suggest that HT with natural estrogens affects a much smaller number of genes and has less-adverse effects on the normal breast in vivo than conventional, synthetic therapy.

Have we come full circle - or moved forward? The Women's Health Initiative 10 years on

In mid-summer 2002, the announcement that the Women's Health Initiative (WHI) trial of combination hormone therapy (HRT) had stopped jolted the field of women's health. It set off a cascade that first stunned, then meaningfully changed the future for millions of women, their partners, and tens of thousands of clinicians and scientists. With 10 years' hindsight, we can begin to put the lessons learned from the WHI HRT trials into perspective. These trials were primarily designed to test whether women considerably past menopause, and mostly asymptomatic, experienced treatment benefits from HRT expected from studies of generally symptomatic women who started near menopause. The definitive answer was 'no'. Unfortunately, the findings were generalized to all postmenopausal women regardless of age. Data accumulated from the WHI and other studies over the past decade have shown that, in women with symptoms or other indications, initiating HRT near menopause - the classic pattern of use - will probably provide a favorable benefit : risk ratio. Spurred by the WHI, many hypotheses and some insights about potential mechanisms for HRT effects on diverse organ systems have emerged, along with new perspectives on regimens, compounds, and routes of administration. This overview provides an historical perspective on the WHI design and the evolution of its message; summarizes current perspectives and insights contributed by eminent colleagues; reviews the state of the art; and looks to the future. We have come full circle in some ways, with mounting evidence supporting benefit for HRT started near menopause and with hard lessons learned about pathophysiology, publicity and interpreting data. Now we move on.

Multiple nuclear receptor signaling pathways mediate the actions of synthetic progestins in target cells

Synthetic progestins are used clinically to treat a variety of women's health issues. Although progestins are designed to signal through the progesterone receptor (PR) to elicit specific pharmacological effects, they can also variably bind to and influence the activity of other nuclear receptors within target tissues, particularly the androgen and glucocorticoid receptors and, in some cases, they regulate mineralocorticoid and estrogen receptors. This article reviews current knowledge on progestin cross-talk to nuclear receptors other than PR, their resultant effect on receptor function in different in vitro models and the potential consequences of this activity for breast, ovarian and endometrial cancer. The impact of cell and tissue context, assay type, steroid metabolism and hormonal milieu in determining progestin-mediated activity are also presented. Collectively this review highlights the complexity of progestin action and the need for consideration of multiple mechanisms that act in concert to influence their ultimate biological activity.

Diabetes, metformin, and breast cancer in postmenopausal women

PURPOSE

Emerging evidence suggests that metformin may reduce breast cancer incidence, but reports are mixed and few provide information on tumor characteristics. Therefore, we assessed associations among diabetes, metformin use, and breast cancer in postmenopausal women participating in Women's Health Initiative clinical trials.

PATIENTS AND METHODS

In all, 68,019 postmenopausal women, including 3,401 with diabetes at study entry, were observed over a mean of 11.8 years with 3,273 invasive breast cancers diagnosed. Diabetes incidence status was collected throughout follow-up, with medication information collected at baseline and years 1, 3, 6, and 9. Breast cancers were confirmed by review of central medical records and pathology reports. Cox proportional hazards regression, adjusted for breast cancer risk factors, compared breast cancer incidence in women with diabetes who were metformin users or nonusers with breast cancer incidence in women without diabetes.

RESULTS

Compared with that in women without diabetes, breast cancer incidence in women with diabetes differed by diabetes medication type (P = .04). Women with diabetes receiving medications other than metformin had a slightly higher incidence of breast cancer (hazard ratio [HR], 1.16; 95% CI, 0.93 to 1.45), and women with diabetes who were given metformin had lower breast cancer incidence (HR, 0.75; 95% CI, 0.57 to 0.99). The association was observed for cancers positive for both estrogen receptor and progesterone receptor and those that were negative for human epidermal growth factor receptor 2.

CONCLUSION

Metformin use in postmenopausal women with diabetes was associated with lower incidence of invasive breast cancer. These results can inform future studies evaluating metformin use in breast cancer management and prevention.