Mammographic density changes during different postmenopausal hormone replacement therapies

Hormone replacement therapy and mammographic density: a systematic literature review

PURPOSE

Hormone replacement therapy (HRT) is used to reduce climacteric symptoms of menopause and prevent osteoporosis; however, it increases risk of breast cancer. Mammographic density (MD) is also a strong risk factor for breast cancer. We conducted this review to investigate the association between HRT use and MD and to assess the effect of different HRT regimens on MD.

METHODS

Two of authors examined articles published between 2002 and 2019 from PubMed, Embase, and OVID using Covidence systematic review platform. Any disagreements were discussed until consensus was reached. The protocol used in this review was created in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Quality of each eligible study was assessed using the Oxford Center for Evidence-Based Medicine (OCEBM) hierarchy.

RESULTS

Twenty-two studies met the inclusion criteria. Six studies showed that using estrogen plus progestin (E + P) HRT was associated with higher MD than estrogen alone. Four studies reported that continuous estrogen plus progestin (CEP) users had higher MD than sequential estrogen plus progestin (SEP) and estrogen alone users. However, two studies showed that SEP users had slightly higher MD than CEP users and estrogen alone users.

CONCLUSIONS

Epidemiological evidence is rather consistent suggesting that there is a positive association between HRT use and MD with the highest increase in MD among current users, and CEP users. Our results suggest that due to increase in MD and masking effect, current E + P users may require additional screening procedures, shorter screening intervals, or using advanced imaging techniques.

Hormone replacement therapy, mammographic density, and breast cancer risk: a cohort study

Purpose

Hormone replacement therapy (HRT) use increases breast cancer risk and mammographic density (MD). We examine whether MD mediates or modifies the association of HRT with the breast cancer.

Methods

For the 4,501 participants in the Danish diet, cancer and health cohort (1993–1997) who attended mammographic screening in Copenhagen (1993–2001), MD (mixed/dense or fatty) was assessed at the first screening after cohort entry. HRT use was assessed by questionnaire and breast cancer diagnoses until 2012 obtained from the Danish cancer registry. The associations of HRT with MD and with breast cancer were analyzed separately using Cox’s regression. Mediation analyses were used to estimate proportion [with 95% confidence intervals (CI)] of an association between HRT and breast cancer mediated by MD.

Results

2,444 (54.3%) women had mixed/dense breasts, 229 (5.4%) developed breast cancer, and 35.9% were current HRT users at enrollment. Compared to never users, current HRT use was statistically significantly associated with having mixed/dense breasts (relative risk and 95% CI 1.24; 1.14–1.35), and higher risk of breast cancer (hazard ratio 1.87; 1.40–2.48). Association between current HRT use and breast cancer risk was partially mediated by MD (percent mediated = 10%; 95% CI 4–22%). The current HRT use-related breast cancer risk was higher in women with mixed/dense (1.94; 1.37–3.87) than fatty (1.37; 0.80–2.35) breasts (p value for interaction = 0.15).

Conclusions

MD partially mediates some of the association between HRT and breast cancer risk. The association between HRT and breast cancer seems to be stronger in women with dense breasts.

Assessment of mammographic density in postmenopausal women during long term hormone replacement therapy

OBJECTIVE

To assess long-term effects of different hormone replacement therapy (HRT) regimens on mammographic density.

METHODS

One hundred sixty-five postmenopausal women were treated with the same HRT during 5 years: 38 received transdermal estradiol, 78 cyclic combined therapy and 49 continuous combined therapy. Mammograms were obtained at baseline, at 1-year and 5-year treatment. Breast density changes were categorized as slight focal increased density, considerable focal increased density, slight diffuse increased density and considerable diffuse increased density.

RESULTS

Mammographic density increased in 7.9% of women receiving estrogen alone versus 25.2% of women receiving combined therapy (p < 0.022) during 1 year, and in 7.9% of women versus 28.3% of women (p < 0.009) after 5 years of therapy, respectively. There were significant statistical differences in women treated with estrogen alone versus those treated with combined HRT after 1 and 5 years. After 5 years of HRT, breast density increased 21.8% in women receiving cyclic combined therapy versus 38.8% in those under continuous combined therapy (p < 0.039).

CONCLUSION

An increase in breast density is significantly more frequent in women receiving combined estrogen-progestin therapy than in women receiving estrogen alone. There are differences between cyclic and continuous combined therapy at 5 years of treatment.

Alcohol consumption before and after breast cancer diagnosis: associations with survival from breast cancer, cardiovascular disease, and other causes

PURPOSE

Alcohol intake is associated with increased risk of breast cancer. In contrast, the relation between alcohol consumption and breast cancer survival is less clear.

PATIENTS AND METHODS

We assessed pre- and postdiagnostic alcohol intake in a cohort of 22,890 women with incident invasive breast cancer who were residents of Wisconsin, Massachusetts, or New Hampshire and diagnosed from 198 to 200 at ages 20 to 79 years. All women reported on prediagnostic intake; a subsample of 4,881 reported on postdiagnostic intake.

RESULTS

During a median follow-up of 11.3 years from diagnosis, 7,780 deaths occurred, including 3,484 resulting from breast cancer. Hazard ratios (HR) and 95% CIs were estimated. Based on a quadratic analysis, moderate alcohol consumption before diagnosis was modestly associated with disease-specific survival (compared with nondrinkers, HR = 0.93 [95% CI, 0.85 to 1.02], 0.85 [95% CI, 0.75 to 0.95], 0.88 [95% CI, 0.75 to 1.02], and 0.89 [95% CI, 0.77 to 1.04] for two or more, three to six, seven to nine, and ≥ 10 drinks/wk, respectively). Alcohol consumption after diagnosis was not associated with disease-specific survival (compared with nondrinkers, HR = 0.88 [95% CI, 0.61 to 1.27], 0.80 [95% CI, 0.49 to 1.32], 1.01 [95% CI, 0.55 to 1.87], and 0.83 [95% CI, 0.45 to 1.54] for two or more, three to six, seven to nine, and ≥ 10 drinks/wk, respectively). Results did not vary by beverage type. Women consuming moderate levels of alcohol, either before or after diagnosis, experienced better cardiovascular and overall survival than nondrinkers.

CONCLUSION

Overall alcohol consumption before diagnosis was not associated with disease-specific survival, but we found a suggestion favoring moderate consumption. There was no evidence for an association with postdiagnosis alcohol intake and breast cancer survival. This study, however, does provide support for a benefit of limited alcohol intake for cardiovascular and overall survival in women with breast cancer.

Type of hormone therapy and risk of misclassification at mammography screening

OBJECTIVE

Current users of hormone therapy (HT) are known to have a lower accuracy of mammography screening than do never users. We studied whether the risk of misclassification depends on type of hormone, administration, regimen, and dose of the therapy.

METHODS

We linked data from mammography screening registers with drug prescription registers from Fyn, Denmark to identify current and never HT users among screening participants. We compared false-positive risks and interval cancer proportions between current users of different HT preparations, taking women's age, breast density, screen number, and age of comparison mammogram into account.

RESULTS

Estrogen therapy users had a significantly higher false-positive risk when the administration was by injection instead of oral (relative risk [RR], 2.37; 95% CI, 1.37-4.09). Women using sequential estrogen plus progestogen therapy had a significantly higher false-positive risk (RR, 1.94; 95% CI, 1.16-3.26) and a nonsignificantly higher interval cancer proportion (RR, 4.29; 95% CI, 0.69-26.53) when the administration of both hormones was transdermal instead of oral. Using tibolone instead of comparable hormones gave a nonsignificantly lower false-positive risk and a nonsignificantly higher interval cancer proportion.

CONCLUSIONS

Our data showed increased risks of misclassification at mammography screening among women using estrogen injections or transdermal, sequential estrogen plus progestogen. Tibolone seems to offer no advantage regarding accuracy of screening mammography.

Breast density changes associated with postmenopausal hormone therapy: post hoc radiologist- and computer-based analyses

OBJECTIVE

The aim of this study was to assess the impact of oral hormone therapy (HT) on breast density in postmenopausal women and to compare the use of computer-based automated approaches for the assessment of breast density with reference to traditional methods.

METHODS

Low-dose oral estrogen (1 mg) continuously combined with drospirenone (2 mg) was administered to postmenopausal women for up to 2 years (26 treatment cycles, 28 d/cycle) in a randomized, placebo-controlled trial. This post hoc analysis assessed the changes in breast density measured from digitized images by two radiologist-based approaches (Breast Imaging Reporting and Data System score and interactive threshold) and one computer-based technique (heterogeneity examination of radiographs). Correlations of temporal changes in breast density with changes in serum estradiol levels, biochemical markers of bone metabolism, and bone mineral density at the spine and femur were also assessed.

RESULTS

Breast density assessed by the radiologist-based approaches increased significantly from baseline in the HT group (P < 0.01), with significant divergence from placebo at 2 years (P < 0.01). Heterogeneity examination of radiograph score by computer-based technique was unchanged in the HT group and decreased significantly with placebo (P < 0.001) to produce a significant group divergence (P < 0.05). Changes in mammographic markers by radiologist- and computer-based approaches correlated with each other in the HT group (P < 0.01) but not in the placebo group.

CONCLUSIONS

HT for 2 years in postmenopausal women significantly increased radiologist-assessed breast density compared with placebo, in addition to significant changes in estrogen levels, markers of bone metabolism, and bone mineral density. Computer-automated techniques may be comparable with and offer advantages over traditional methods.

Hormone replacement therapy and breast density changes

OBJECTIVES

To compare the incidence of increased breast density and tenderness in postmenopausal women associated with transdermal (Estalis/Combipatch), Novartis, Basel, Switzerland) and oral (Kliogest), Schering AG, Berlin, Germany) hormone replacement therapy (HRT).

METHODS

A total of 202 postmenopausal women were randomized to transdermal or oral HRT. Mammograms obtained at study entry and after 1 year of treatment were assessed for percent breast density by means of the digital segmentation and thresholding technique. Breast tenderness was assessed at each study visit.

RESULTS

The mean breast density by ANCOVA after adjusting for screening value at study end was significantly lower for women using Estalis (38.4%, standard error 0.9%) compared with Kliogest (46.9%, standard error 1.5%) (p<0.0001). Significantly fewer women using transdermal HRT had an increase in mammographic breast density or breast tenderness compared to oral HRT. Of the women using transdermal HRT, 39.1% had no change in breast density compared to 15.7% for women using oral HRT. Only 4% of women using transdermal HRT had a marked increase in density (>25%) compared to 15.7% of women using oral HRT. Overall, 36.0% of patients in the transdermal group reported breast tenderness at some point during the 1-year study, compared with 57.6% in the oral HRT group (p=0.0002).

CONCLUSION

Transdermal HRT use is associated with a significantly lower incidence of increased mammographic breast density and breast tenderness compared with oral HRT.

Could transdermal estradiol + progesterone be a safer postmenopausal HRT? A review

Hormone replacement therapy (HRT) in young postmenopausal women is a safe and effective tool to counteract climacteric symptoms and to prevent long-term degenerative diseases, such as osteoporotic fractures, cardiovascular disease, diabetes mellitus and possibly cognitive impairment. The different types of HRT offer to many extent comparable efficacies on symptoms control; however, the expert selection of specific compounds, doses or routes of administration can provide significant clinical advantages. This paper reviews the role of the non-oral route of administration of sex steroids in the clinical management of postmenopausal women. Non-orally administered estrogens, minimizing the hepatic induction of clotting factors and others proteins associated with the first-pass effect, are associated with potential advantages on the cardiovascular system. In particular, the risk of developing deep vein thrombosis or pulmonary thromboembolism is negligible in comparison to that associated with oral estrogens. In addition, recent indications suggest potential advantages for blood pressure control with non-oral estrogens. To the same extent, a growing literature suggests that the progestins used in association with estrogens may not be equivalent. Recent evidence indeed shows that natural progesterone displays a favorable action on the vessels and on the brain, while this might not be true for some synthetic progestins. Compelling indications also exist that differences might also be present for the risk of developing breast cancer, with recent trials indicating that the association of natural progesterone with estrogens confers less or even no risk of breast cancer as opposed to the use of other synthetic progestins. In conclusion, while all types of hormone replacement therapies are safe and effective and confer significant benefits in the long-term when initiated in young postmenopausal women, in specific clinical settings the choice of the transdermal route of administration of estrogens and the use of natural progesterone might offer significant benefits and added safety.

Tibolone: the way to beat many a postmenopausal ailments

OBJECTIVE

The effects of tibolone on climacteric symptoms, osteoporosis, cardiovascular disease, breasts and the endometrium are summarised, and its role in clinical practice is reviewed in this article.

BACKGROUND

Tibolone has tissue-specific effects on receptors and enzymes that influence the synthesis and metabolism of endogenous sexual steroid hormones.

METHODS

This evaluation was based on the findings from several randomised studies, which addressed the basic and clinical research on tibolone.

RESULTS/CONCLUSION

Clinical trials prove that tibolone is effective in the treatment of the menopausal symptoms and for the postponement and calming of symptoms accompanying age-related diseases. The findings of basic researchers that tibolone affects the metabolism of every cell, including malignant cells, opened a door to a whole new domain of research that has a promising future.

Quantifying effect-specific mammographic density

A methodology is introduced for the automated assessment of structural changes of breast tissue in mammograms. It employs a generic machine learning framework and provides objective breast density measures quantifying the specific biological effects of interest. In several illustrative experiments on data from a clinical trial, it is shown that the proposed method can quantify effects caused by hormone replacement therapy (HRT) at least as good as standard methods. Most interestingly, the separation of subpopulations using our approach is considerably better than the best alternative, which is interactive. Moreover, the automated method is capable of detecting age effects where standard methodologies completely fail.

Mammographic densities during the menopausal transition: a longitudinal study of Australian-born women

OBJECTIVE

The objective of this study was to investigate hormonal and other factors associated with mammographic density during the menopausal transition and in postmenopause.

DESIGN

Mammograms were obtained from 252 participants in the Melbourne Women's Midlife Health Project-a longitudinal population-based study that included annual interviews, blood collection, and physical measurements; 869 original films of the right craniocaudal view were digitized. Total area of the breast and the area of dense tissue were measured, and the percentage of mammographically dense tissue (PMD) was calculated. Data were analyzed using time-series regression models.

RESULTS

Of the 252 women, 87% had more than one mammogram, and the mean age was 56.0 (SD 3.6) years (range 45-67); 129 women who had never used hormone therapy were included in the analyses. The mean nondense breast tissue area increased through the menopausal transition (P for trend=0.01), there was no significant trend in the mean dense breast tissue area, and mean PMD decreased (P for trend=0.004). Multivariate analysis showed that increasing age (P<0.005) and body mass index (BMI) (P<0.05), having had children (P<0.05), and higher than average free testosterone levels (P<0.05) (or lower than average sex hormone-binding globulin levels) were associated with increased area of nondense tissue. Increasing age (P<0.05) and BMI (P<0.05) were associated with decreased PMD. There was a tendency for higher than average free testosterone levels (P<0.07) and having had children (P=0.07) to be associated with lower PMD. After controlling for age, there were no significant associations with the area of dense tissue.

CONCLUSIONS

This longitudinal observational study has shown that after controlling for age, there was no apparent effect of menopausal change on the area of dense breast tissue. Aging and increasing BMI through the menopausal transition were associated with increased nondense breast tissue and explain a small, but statistically significant, portion of the variation in PMD tissue.

Hormone replacement therapy

HRT should not be used for the prevention or treatment of chronic disease (eg, heart disease, osteoporosis, dementia). HRT is effective in alleviating moderate to severe menopausal symptoms. Clinicians must be aware of the risks and benefits of HRT and discuss them thoroughly with their patients. As new forms and lower doses of hormones become available, additional studies will be needed to compare therapeutic strategies adequately. Studies of younger perimenopausal and menopausal women are needed. Whatever regimen is chosen, the lowest allowable estrogen dose to relieve symptoms for the shortest time is recommended. Alternatives to hormonal therapy are being examined and some may be considered. Table 1 provides an evidence-based summary of current recommendations.

Tibolone and breast cancer

Tibolone is a relatively new drug for postmenopausal women, which is structurally related to 19-nortestosterone derivatives and exhibits weak oestrogenic, progestogenic and androgenic activities. The effect of tibolone on breast tissue is still obscure. In vitro studies have shown conflicting results regarding the effects of tibolone on breast cells. On the other hand, although epidemiological studies show an increase in the risk of breast cancer among women treated with tibolone, accumulation of data obtained from radiological studies presents promising results. However, the safety of tibolone with regard to breast tissue needs to be investigated further, especially through well-designed, large-scale, randomised-controlled trials.

Do breast cancer risk factors modify the association between hormone therapy and mammographic breast density? (United States)

OBJECTIVE

To evaluate whether the association between hormone therapy (HT) and breast density differs by levels of breast cancer risk factors.

METHODS

We evaluated 80,867 screening mammograms from 39,296 postmenopausal women from Washington State. We estimated odds ratios and 95% confidence intervals for dense breasts (Breast Imaging Reporting and Data System categories 3 "heterogeneously dense" and 4 "extremely dense") compared to fatty breasts (categories 1 "almost entirely fat" and 2 "scattered fibroglandular") among HT users compared to never users. We separately examined former HT use and current HT use by type (estrogen plus progestin therapy (EPT) and estrogen-only therapy (ET)). We stratified the associations by age, BMI, race, family history, and reproductive and menopausal factors.

RESULTS

Current EPT users had a 98% (1.87-2.09) greater odds of having dense breasts and current ET users had a 71% (1.56-1.87) greater odds compared to never users. Current HT users were more likely to have dense breasts if they were older, had more children, or younger at first birth compared to never users; these associations were stronger among EPT users than ET users.

CONCLUSIONS

HT, particularly EPT, may reduce protective effects of older age, parity, and younger age at first birth on mammographic density.

Determinants of false positive recall in an Australian mammographic screening program

We conducted a case-control study (n=30128) to assess the importance of clinical (e.g., family history, age, hormone replacement therapy (HRT) use and duration) and service-related characteristics (e.g., time since introduction of Kodak MINR2000 film, year of screen) for false positive (FP) recall at BreastScreen Victoria, Australia. There was an age-adjusted upward trend in FP recall rates with year of screen at first (odds ratio (OR) 1.11, 95% confidence interval (95% CI) 1.08-1.13) and subsequent rounds (OR 1.04, 95% CI 1.01-1.06). In the multivariate analysis, the upward trend only remained for first round and age and family history also remained statistically significant at first round. At subsequent rounds the time since introduction of MINR2000, age, strong family history of breast cancer, use of HRT, recall at previous screen and previous screen at more than 27 months were all important predictors of FP recall. The rise in FP rates with year of screen at first round screening is of concern and may require further training of radiologists to improve confidence when viewing films when there a no films for comparison.

Effects of hormone replacement therapy regimens on mammographic breast density: The role of progestins

AIM

To evaluate the effects of different regimens of hormone replacement therapy (HRT) on mammographic breast density.

METHODS

Mammograms of 113 healthy postmenopausal women who were on different HRT regimens were evaluated retrospectively. All women had a baseline mammography and at least one mammogram after at least 12 months of HRT. Four parenchymal patterns were considered mammographically. Quantification of density changes that occurred on follow-up mammograms was done qualitatively and with reference to densities on baseline mammograms.

RESULTS

Sixty women were treated with a continuous estrogen-progestin combination; 16 with a cyclic estrogen-progestin combination and 37 were with estrogen only. Twenty-six women had increased mammographic density after HRT. Mammographic density increase was detected in 23 women (38.3%) of the continuous estrogen-progestin combination group, two women (12.5%) of the cyclic estrogen-progestin combination group and one woman (2.7%) of the estrogen-only group. Mammographic density increase was more common among women in the continuous estrogen-progestin combination group than the other groups and this difference was found to be statistically significant (P < 0.001). Breast density increase was observed in 18 of 30 women (60%) with higher doses of progestin compared to 5 of 30 women (16.7%) with lower dose (P < 0.05).

CONCLUSIONS

Postmenopausal HRT may increase mammographic breast density. Breast density appears to be mostly affected by higher doses and continuous administration of progestin.

Tibolone and its metabolites inhibit invasion of human mammary carcinoma cells in vitro

Tibolone is used in postmenopausal women to alleviate menopausal symptoms and to prevent osteoporosis, but it does not stimulate the endometrium and the breast. Up to date, little data are available on the effect of tibolone on breast cancer initiation and progression.

OBJECTIVE

In the present in vitro study, we investigated the effect of tibolone and its metabolites (3alpha-OH tibolone, 3beta-OH tibolone, the Delta4 isomer and the sulphated isoform) on invasion of human breast cancer cells.

METHODS

The effect on invasion was evaluated in the chick heart invasion assay using MCF-7/6 cells and in the collagen type I invasion assay using T47-D cells. Furthermore, the compounds were tested in aggregation and migration assays.

RESULTS

We observed that, at a concentration of 100 microM, tibolone and its 3beta-OH metabolite possess anti-invasive activities in the two different invasion assays. However, this was neither due to effects on cell-cell adhesion nor on motility. In an attempt to probe the mechanism underlying the anti-invasive effect, we found that pro-MMP-9 release was markedly reduced in the supernatant of MCF-7/6 breast cancer cells treated with tibolone, 3alpha-OH tibolone and the Delta4 isomer but, interestingly, not with the sulphated metabolite.

CONCLUSION

We conclude that tibolone and its 3beta-OH metabolite have an anti-invasive effect on the tested breast cancer cell lines in vitro. This effect on invasion is not correlated with an effect on cell-cell adhesion or motility but coincides with a decreased release of pro-MMP-9 in the medium.

Le profil clinique des femmes qui utilisent la tibolone est-il le même que celui des femmes utilisant un traitement hormonal classique ? Données d'une enquête nationale en France

OBJECTIVES

To compare the pre-existing risk profiles for breast or endometrial cancer of menopaused women receiving tibolone or another hormone replacement therapy in France, with a view to examining the possibility of biases of selection of patients and of detection of these cancers in the Million Women Study.

PATIENTS AND METHODS

Nationwide survey conducted in France among a representative sample of 153 gynaecologists. The particulars of the last two consulting menopaused women treated with tibolone (N = 306) and of the last two treated with a classical estrogen-progestogen therapy (N = 306) were collated then analysed.

RESULTS

Compared to those treated with a classical estrogen-progestogen therapy, more women receiving tibolone were aged 60 years or over (40 vs 31%; P < 0.01). More of them had risk factors for breast cancer (history of mastodynia or mastopathy, elevated mammographic breast density) (6 vs 50%; P < 0.01). More of them had a history of uterine investigation or exploration or of irregular bleeding (61 vs 53% of women with a history of irregular bleeding; P < 0.05). Overall, 84% of women treated with tibolone had at least one risk factor for breast or endometrial cancer vs 75% of those receiving a classical estrogen-progestogen therapy (P < 0.01).

DISCUSSION AND CONCLUSION

Owing to its specific properties, tibolone is generally prescribed to women with a higher risk profile for breast or endometrial cancer than those receiving a classical estrogen-progestogen therapy, which may entail patient selection and cancer detection biases in non-randomised, open-label, observational studies.

Hormone replacement therapy and false positive recall in the Million Women Study: patterns of use, hormonal constituents and consistency of effect

INTRODUCTION

Current and recent users of hormone replacement therapy (HRT) have an increased risk of being recalled to assessment at mammography without breast cancer being diagnosed ('false positive recall'), but there is limited information on the effects of different patterns of HRT use on this. The aim of this study is to investigate in detail the relationship between patterns of use of HRT and false positive recall.

METHODS

A total of 87,967 postmenopausal women aged 50 to 64 years attending routine breast cancer screening at 10 UK National Health Service Breast Screening Units from 1996 to 1998 joined the Million Women Study by completing a questionnaire before screening and were followed for their screening outcome.

RESULTS

Overall, 399 (0.5%) participants were diagnosed with breast cancer and 2,629 (3.0%) had false positive recall. Compared to never users of HRT, the adjusted relative risk (95% CI) of false positive recall was: 1.62 (1.43-1.83), 1.80 (1.62-2.01) and 0.76 (0.52-1.10) in current users of oestrogen-only HRT, oestrogen-progestagen HRT and tibolone, respectively (p (heterogeneity) < 0.0001); 1.65 (1.43-1.91), 1.49 (1.22-1.81) and 2.11 (1.45-3.07) for current HRT used orally, transdermally or via an implant, respectively (p (heterogeneity) = 0.2); and 1.84 (1.67-2.04) and 1.75 (1.49-2.06) for sequential and continuous oestrogen-progestagen HRT, respectively (p (heterogeneity) = 0.6). The relative risk of false positive recall among current users appeared to increase with increasing time since menopause, but did not vary significantly according to any other factors examined, including duration of use, hormonal constituents, dose, whether single- or two-view screening was used, or the woman's personal characteristics.

CONCLUSION

Current use of oestrogen-only and oestrogen-progestagen HRT, but not tibolone, increases the risk of false positive recall at screening.

Associations among circulating sex hormones, insulin-like growth factor, lipids, and mammographic density in postmenopausal women

OBJECTIVE

Hormone therapy use has been positively associated with mammographic density in several studies. However, few studies have examined the association between endogenous hormone levels and mammographic density. Therefore, we evaluated the relationship of endogenous sex hormones, insulin-like growth factor (IGF), and lipids with mammographic density in 88 overweight, postmenopausal women not taking hormone therapy.

METHODS

Percent density and dense area were evaluated as continuous measures using a computer-assisted program. We used multiple linear regression to evaluate the associations of sex hormones, IGF, and cholesterol with mammographic density, adjusting for confounders, including adiposity. We evaluated stratification by history of hormone therapy use (former versus never) and hormone therapy latency (<5 versus > or = 5 years).

RESULTS

Among former hormone therapy users, mammographic density was inversely associated with circulating levels of estrone (P = 0.01), estradiol (P = 0.003), free estradiol (P = 0.004), testosterone (P = 0.04), free testosterone (P = 0.02), androstenedione (P < 0.001), dehydroepiandrosterone (P = 0.01), and the ratio of IGF-I to its binding protein (IGF-I/IGFBP-3; P = 0.04). We found similar associations when we limited the analyses to women who had used hormone therapy within the past 5 years. We also noted positive associations of mammographic density with total cholesterol (P = 0.03) and low-density lipoprotein (P = 0.03) among former hormone therapy users. No associations were noted among women who had never used hormone therapy.

CONCLUSIONS

These results suggest that there is an inverse relationship between endogenous sex hormones and mammographic density in postmenopausal women among former users of hormone therapy. This is not consistent with the hormone therapy literature and should be confirmed in larger studies.

The relationship between mammographic density and duration of hormone therapy: effects of estrogen and estrogen–progestin

BACKGROUND

The purpose of this study was to examine the effects of duration of hormone therapy (HT) and treatment regimens on mammographic density.

METHODS

A retrospective study was carried out of of 467 post-menopausal women who received estrogen or estrogen-progestin and had regular mammographic density determination by the Breast Imaging Reporting and Data System between 1994 and 2001.

RESULTS

The fraction of women using HT who had an increase in mammographic density became more important over time. Further analysis of the effects of regimens after 4 years of HT shows that the increase in mean density was much greater in women receiving combined HT than in those receiving estrogen alone. The incidence of increased mammographic density showed significantly progressive increases over the duration of combined HT from 7.5 to 22.4%.

CONCLUSIONS

Although most women using HT maintained breast density at pre-treatment levels, there is a note of caution for women using long-term HT, especially those using combined estrogen-progestin.

Influence of different HRT regimens on mammographic density

OBJECTIVES

A prospective, randomized, open-label study was conducted to evaluate effects on mammographic density in postmenopausal and late perimenopausal women receiving continuous combined or sequential combined hormone replacement therapy (HRT).

METHODS

The subjects were randomized to treatment with low-dose continuous combined HRT containing 1 mg 17beta-estradiol plus 0.5 mg norethisterone acetate (Activelle) or a sequential combined HRT regimen consisting of 0.625 mg conjugated equine estrogens for 28 days plus 5 mg medrogestone for 14 days (Presomen). Mammograms were obtained at baseline and after 9 cycles (each 28 days) of treatment.

RESULTS

The majority of women (approximately two-thirds in each treatment group) had no changes in mammographic breast density between baseline and the final study visit. There were no marked differences between treatment groups. Approximately 20% of women in both groups had a slight increase in mammographic density. Only 10-14% of women in both groups had a pronounced increase in mammographic density. The analyses of the degree of change showed no remarkable differences between treatments.

CONCLUSION

These results indicate that the increase in mammographic density with a low-dose continuous combined HRT regimen is no greater than that with a sequential combined HRT regimen. The type of progestogen does not have an impact on the extent of mammographic density changes.

Thérapeutiques hormonales de la ménopause : impact sur la densité mammographique

Whether qualitative-classified or quantitative-measured, mammographic density, which changes according to physiological variations, is nowadays commonly recognized as a factor increasing the relative risk of breast cancer. The present review aims at clarifying the impact of menopausal hormonal therapies on mammographic density. Neither Tibolone nor Raloxifene seem to have any negative impact on mammographic density. In some instances, oestrogens-progestin hormonal replacement therapies may increase mammographic density and thus reduce sensitivity and specificity of screening mammograms. Shorter intervals between mammographies combined with additional physical examination and breast ultrasonography appear to be the best way to reduce interval cancers.

Postmenopausal hormone therapy and the risk of breast cancer

Reports from the Women's Health Initiative (WHI) and the Million Women Study have indicated that postmenopausal hormone therapy increases the risk of breast cancer. At this point in time, it is not certain whether these data reflect a small increase in risk or an impact of hormone therapy on pre-existing tumors. The purpose of this review is to provide an analysis of the epidemiologic data that can help the clinician inform patients and assist patients in their decision-making.

Hormones and mammographic breast density

Mammographic density reveals information about the hormonal environment along with the heritability in which breast cancer develops. This is made possible by the widespread use of population screening by mammography. Increasingly this is an important observation not just for population studies, which reveal disease determinants, but also for the individual. Density reveals the effect of the intrinsic hormonal environment and its background genetics, and also the effect of pharmaceuticals--agents used for disease control and prevention and hormone replacement therapy (HRT) used for well-being around the menopause. Increasingly this focus on the individual will need methods of measurement of density that can be monitored with greater accuracy than the widely used BI-RADS 4 categories. For this purpose studies are under way to measure volume of dense tissue as a continuous variable. In due course, measurement of density will be used as a biomarker of risk, employed in risk models and to monitor interventions. Before this can happen more knowledge will be needed of the change occurring naturally through the menopause and the differences between individuals. This will need specific study backed up with detailed information about the patient on large numbers of women and their mammograms. Currently the widespread use of HRT has increased the prevalence of the dense patterns and potentially may adversely affect the effectiveness of mammographic screening programmes. There is a large literature recording this from which we see that combined continuous preparations of oestrogen progestin are more likely to cause increased density than oestrogen alone or tibolone. Breast density, measured more accurately, has the potential to be an important adjunct to risk estimation and to monitor interventions for breast cancer prevention with pharmaceuticals (such as SERMS) and by change in lifestyle behaviours.

The effects of tibolone and oestrogen-based HT on breast cell proliferation and mammographic density

Tibolone is a tissue-selective compound used for the treatment of climacteric symptoms and the prevention of osteoporosis in post-menopausal women. In this review some in vitro data and clinical studies indicating that the effects of tibolone on breast tissue are different from those seen with oestrogen-based hormone therapy (HT) are briefly discussed. From a clinical perspective, an increase in mammographic density and breast cell proliferation should be regarded as an unwanted side-effect of HT. Efforts should therefore be made to define treatment regimens for post-menopausal women that have minimal effects on the breast but still maintain the many advantages of HT. Data suggest that tibolone may be such an alternative.

Treatment of menopause-associated vasomotor symptoms: position statement of The North American Menopause Society

OBJECTIVE

To create an evidence-based position statement regarding the treatment of vasomotor symptoms associated with menopause.

DESIGN

The North American Menopause Society (NAMS) enlisted clinicians and researchers acknowledged to be experts in the field of menopause-associated vasomotor symptoms to review the evidence obtained from the medical literature and develop a document for final approval by the NAMS Board of Trustees.

RESULTS

For mild hot flashes, lifestyle-related strategies such as keeping the core body temperature cool, participating in regular exercise, and using paced respiration have shown some efficacy without adverse effects. Among nonprescription remedies, clinical trial results are insufficient to either support or refute efficacy for soy foods and isoflavone supplements (from either soy or red clover), black cohosh, or vitamin E; however, no serious side effects have been associated with short-term use of these therapies. Single clinical trials have found no benefit for dong quai, evening primrose oil, ginseng, a Chinese herbal mixture, acupuncture, or magnet therapy. Few data support the efficacy of topical progesterone cream; safety concerns should be the same as for other progestogen preparations. No clinical trials have been conducted on the use of licorice for hot flashes. Among nonhormonal prescription options, the antidepressants venlafaxine, paroxetine, and fluoxetine and the anticonvulsant gabapentin have demonstrated some efficacy for treating hot flashes and were well tolerated. Two antihypertensive agents, clonidine and methyldopa, have shown modest efficacy but with a relatively high rate of adverse effects. For moderate to severe hot flashes, systemic estrogen therapy, either alone (ET) or combined with progestogen (EPT) or in the form of estrogen-progestin oral contraceptives, has been shown to significantly reduce hot flash frequency and severity. Clinical trials have associated ET/EPT with adverse effects, including breast cancer, stroke, and thromboembolism. Several progestogens (both oral and intramuscular formulations) have shown efficacy in treating hot flashes, including women with a history of breast cancer, although no definitive data are available on long-term safety in these women.

CONCLUSIONS

In women who need relief for mild vasomotor symptoms, NAMS recommends first considering lifestyle changes, either alone or combined with a nonprescription remedy, such as dietary isoflavones, black cohosh, or vitamin E. Prescription systemic estrogen-containing products remain the therapeutic standard for moderate to severe menopause-related hot flashes. Recommended options for women with concerns or contraindications relating to estrogen-containing treatments include prescription progestogens, venlafaxine, paroxetine, fluoxetine, or gabapentin. Clinicians are advised to enlist women's participation in decision making when weighing the benefits, harms, and scientific uncertainties of therapeutic options. Regardless of the management strategy adopted, treatment should be periodically reassessed as menopause-related vasomotor symptoms will abate over time without any intervention in most women.

Increased risk of breast cancer following different regimens of hormone replacement therapy frequently used in Europe

Epidemiologic studies have shown an increased risk of breast cancer following hormone replacement therapy (HRT). The aim of this study was to investigate whether different treatment regimens or the androgenecity of progestins influence the risk of breast cancer differently. The Danish Nurse Cohort was established in 1993, where all female nurses aged 45 years and above received a mailed questionnaire (n = 23,178). A total of 19,898 women returned the questionnaire (86%). The questionnaire included information on HRT types and regimens, reproductive history and lifestyle-related factors. Breast cancer cases were ascertained using nationwide registries. The follow-up ended on 31 December 1999. Women with former cancer diagnoses, women with missing information on HRT, surgical menopause, premenopausal, as well as hysterectomized women were excluded, leaving 10,874 for analyses. Statistical analyses were performed using Cox proportional hazards model. A total of 244 women developed breast cancer during follow-up. After adjustment for confounding factors, an increased risk of breast cancer was found for the current use of estrogen only (RR = 1.96; 95% CI = 1.16-3.35), for the combined use of estrogen and progestin (RR = 2.70; 95% CI = 1.96-3.73) and for current users of tibolone (RR = 4.27; 95% CI = 1.74-10.51) compared to the never use of HRT. In current users of combined HRT with testosterone-like progestins, the continuous combined regimens were associated with a statistically significant higher risk of breast cancer than the cyclical combined regimens (RR = 4.16, 95% CI = 2.56-6.75, and RR = 1.94, 95% CI = 1.26-3.00, respectively). An increased risk of breast cancer was noted with longer durations of use for the continuous combined regimens (p for trend = 0.048). The European traditional HRT regimens were associated with an increased risk of breast cancer. The highest risk was found for the use of continuous combined estrogen and progestin.

Quantitative Assessment of Mammographic Breast Density: Relationship with Breast Cancer Risk

Increased mammographic breast density is a moderate independent risk factor for breast cancer, with findings of published studies in which quantitative methods of assessment were used showing a positive association. Breast density may be quantified by using visual assessment or planimetry. Although the category definitions vary, the odds ratio for developing breast cancer for the most dense compared with the least dense breast tissue categories ranges from 1.8 to 6.0, with most studies yielding an odds ratio of 4.0 or greater. Plausible explanations for the association of breast density with increased breast cancer risk may be the development of premalignant lesions such as atypical ductal hyperplasia, elevated growth factors, or increased estrogen production within the breast due to overactive aromatase. The amount of breast density may be due in part to genetic heredity. However, unlike other risk factors, breast density may be influenced. Specifically, breast density is very hormonally responsive and potentially may be influenced by lifestyle factors such as alcohol intake and diet. Assessment of breast density may become useful in risk assessment and prevention decisions.

Effect of tibolone on breast symptoms resulting from postmenopausal hormone replacement therapy

OBJECTIVE

To evaluate the incidence of breast symptoms in a population treated with various hormone replacement therapy (HRT) regimens and to detect the variations in breast symptomatology after HRT changing to tibolone administration.

METHODS

This prospective placebo-controlled clinical trial was conducted on healthy women on HRT reporting breast symptoms. A questionnaire was given to each woman to detect breast symptomatology. Breast tenderness and mastalgia were evaluated using a visual analogue scale (VAS). According to the choice of the each woman with breast symptoms, the HRT was changed to tibolone (2.5 mg/day per os) or to calcium carbonate (1 tab/day, placebo group). The duration of treatment was of 12 months. After 6 and 12 months breast symptomatology was re-evaluated.

RESULTS

Among the 600 screened women, 64 (10.7%) were suffering from breast symptomatology. After 6 and 12 months of treatment with tibolone or placebo, mean VAS score for breast tenderness and for mastalgia resulted significantly (P<0.05) decreased, without differences between groups, in comparison with basal value. Only one woman had no improvement from the breast symptoms with tibolone administration.

CONCLUSIONS

Shifting from classical HRT to tibolone is followed by a significant reduction of breast symptomatology in postmenopausal women with breast complaints similar to that obtained with treatment withdrawal.

The effect of various regimens of hormone replacement therapy on mammographic breast density

OBJECTIVES

To evaluate the effect of three distinct hormone replacement therapy regimens on mammography.

METHODS

121 postmenopausal women who had never received or were past users of hormone replacement therapy were studied prospectively. Women with an intact uterus were randomly allocated either to conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, n=34) or to 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E(2)/NETA, n=35). Hysterectomized women received CEE 0.625 mg (CEE, n=25). Women who either declined or did not qualify for treatment served as controls (n=27). Treatment was continuous and the study period lasted 12 months. Main outcome measures were the changes according to Wolfe classification between baseline and 12-month-mammograms.

RESULTS

No increase in breast density was identified in any of the women in the control group. Two women (8%) in the CEE group showed an increase in breast density. Four women (11.8%) in the CEE/MPA and 11 women (31.4%) in the E(2)/NETA group revealed an increase in breast density. No woman in the therapy groups showed an involution of fibroglandular tissue while seven women (25.9%) in the control group exhibited involution of breast parenchyma.

CONCLUSIONS

Our study suggests that hormone replacement therapy may suspend breast involution but does not increase breast density in the majority of patients. In the minority of patients who show a density increase, the magnitude of this increase varies according to the regimen employed.

Progestins and breast cancer

The relationship between the use of menopausal hormone therapy (ERT, unopposed estrogen therapy; HRT, combined estrogen and progestin therapy) and the development of breast cancer remains controversial. Mechanistic studies examining progestins in human breast cancer cell lines have demonstrated a biphasic cellular response to progesterone; initial exposure to hormone results in a proliferative burst with sustained exposure resulting in growth inhibition. To date, there is no definitive evidence that progestins act in the pathogenesis of breast cancer. Epidemiologic studies have produced inconsistent results, and data from randomized, placebo-controlled trials are limited. Although recent results from the continuous combined therapy arm of the Women's Health Initiative trial showed a small increase in the risk of invasive breast cancer in women on therapy for 5 years or more, a clear consensus regarding the relationship between HRT and breast cancer risk cannot yet be drawn from existing data. Studies have consistently documented that HRT use is associated with improved mortality and survival rates for women with breast cancer. Large-scale, randomized studies on different progestin regimens are needed to critically assess the effect of progestin on breast cancer.

Role of progestogen in hormone therapy for postmenopausal women: position statement of The North American Menopause Society

OBJECTIVE

To create an evidence-based position statement regarding the role of progestogen in postmenopausal hormone therapy (estrogen plus a progestogen, or EPT) for the management of menopause-related symptoms.

DESIGN

NAMS followed the general principles established for evidence-based guidelines to create this document. Clinicians and researchers acknowledged to be experts in the field of postmenopausal hormone therapy were enlisted to review the evidence obtained from the medical literature and develop a position statement for approval by the NAMS Board of Trustees.

RESULTS

The primary role of progestogen in postmenopausal hormone therapy is endometrial protection. Unopposed estrogen therapy (ET) is associated with a significantly increased risk of endometrial hyperplasia and adenocarcinoma. Adding the appropriate dose and duration of progestogen to ET has been shown to lower that risk to the level found in never-users of ET. The clinical goal of progestogen in EPT is to provide endometrial protection while maintaining estrogen benefits and minimizing progestogen-induced side effects, particularly uterine bleeding. EPT discontinuance correlates with uterine bleeding-women with more days of amenorrhea have higher rates of continuance. All US Food and Drug Administration-approved progestogen formulations will provide endometrial protection if the dose and duration are adequate. Progestogens may diminish the beneficial effects of ET on cardiovascular risk factors. However, no EPT (or ET) regimen should be initiated for the primary or secondary prevention of cardiovascular heart disease. Some progestogens may negatively affect mood. Adding progestogen to ET does not decrease the breast cancer risk, although it does not seem to increase mortality. Progestogen increases mammographic density, which is reversed after discontinuation of use. Progestogen has limited effect on the bone-enhancing action of ET. In general, the side effects of added progestogen are mild, although they may be severe in a small percentage of women.

CONCLUSIONS

Progestogen should be added to ET for all postmenopausal women with an intact uterus to prevent the elevated risk of estrogen-induced endometrial hyperplasia and adenocarcinoma. There is no consensus on a preferred regimen for all women. By changing the progestogen type, route, or regimen, clinicians can individualize therapy to minimize side effects, especially uterine bleeding, and limit any effects on ET benefits while providing adequate endometrial protection.

Mammographic changes associated with raloxifene and tibolone therapy in postmenopausal women: a prospective study

OBJECTIVE

The prolonged use of estrogen therapy is associated with a slightly increased risk of breast cancer. Alternative therapies that are effective in the prevention of menopause, having associated morbidities but no unwanted effects, are of primary interest in the pharmacologic research. The aim of this study was to evaluate the effect of two alternative to estrogens drugs, the selective estrogen receptor modulator raloxifene and the tissue-specific tibolone, on the mammographic appearance of the breast.

DESIGN

The study group comprised 131 postmenopausal women aged 41 to 67 years. The women were at least 2 years postmenopausal, free of climacteric symptoms, and at the time of entry to the study had not had therapy for at least 9 months. Women with risk factors for osteoporosis or cardiovascular disease were allocated either to tibolone (n = 56) or raloxifene (n = 48) therapy. Women with no risk factors and women who either did not qualify for or denied treatment (n = 27) served as controls. The study duration was 12 months. Women received a baseline mammogram before commencing therapy and a repeat mammogram at the end of the study period. Mammogram findings were classified according to the modified Wolfe criteria by two expert radiologists.

RESULTS

No difference was identified between groups with respect to baseline characteristics associated with breast cancer risk. Similarly, no difference was detected between groups concerning the modified Wolfe classification of baseline mammographic findings. In the tibolone group, 10.7% of the women showed an increase in breast density in the 12-month reevaluation. The respective figure in the raloxifene group was 6.3%, whereas no woman in the control group showed an increase in breast density. Differences in the increase in breast density between groups did not, however, reach statistical significance. Accordingly, 10.7% of women in the tibolone group and 18.8% of women in the raloxifene group exhibited involutionary changes in the repeat mammogram, whereas 25.9% of women in the control group revealed a decrease in breast density in the 12-month examination. The percentages were not significantly different between groups.

CONCLUSIONS

Breast density as shown by mammography was stable in a majority of patients and changed in a minority of cases for both tibolone and raloxifene. In most patients, these drugs are not likely to interfere with mammogram interpretation. Larger long-term studies are needed to confirm the impact of prolonged tibolone or raloxifene administration on mammography.

Progesterone receptors--animal models and cell signalling in breast cancer. Implications for breast cancer of inclusion of progestins in hormone replacement therapies

Progestins are included in menopausal hormone replacement therapy to counteract the increased risk for endometrial cancer associated with estrogen replacement therapy. Studies of hormone replacement therapy and breast cancer risk and of changes in mammographic density according to different regimens of hormone replacement therapy suggest that, for the most part, estrogen-progestin replacement therapy has a more adverse effect on breast cancer risk than does estrogen replacement therapy. Many questions remain unresolved, however, including risk associated with different regimens of estrogen-progestin replacement therapy, and whether the effects vary according to tumor characteristics, such as histology, extent of disease, and hormone receptor status.