Digitized assessment of mammographic breast density in patients who received low-dose intrauterine levonorgestrel in continuous combination with oral estradiol valerate: a pilot study

Effects of Estradiol/Micronized Progesterone vs. Conjugated Equine Estrogens/Medroxyprogesterone Acetate on Breast Cancer Gene Expression in Healthy Postmenopausal Women

Recent studies suggest estradiol (E₂)/natural progesterone (P) confers less breast cancer risk compared with conjugated equine estrogens (CEE)/synthetic progestogens. We investigate if differences in the regulation of breast cancer-related gene expression could provide some explanation. This study is a subset of a monocentric, 2-way, open observer-blinded, phase 4 randomized controlled trial on healthy postmenopausal women with climacteric symptoms (ClinicalTrials.gov; EUCTR-2005/001016-51). Study medication was two 28-day cycles of sequential hormone treatment with oral 0.625 mg CEE and 5 mg of oral medroxyprogesterone acetate (MPA) or 1.5 mg E₂ as percutaneous gel/day with the addition of 200 mg oral micronized P. MPA and P were added days 15-28/cycle. Material from two core-needle breast biopsies in 15 women in each group was subject to quantitative PCR (Q-PCR). The primary endpoint was a change in breast carcinoma development gene expression. In the first eight consecutive women, RNA was extracted at baseline and after two months of treatment and subjected to microarray for 28856 genes and Ingenuity Pathways Analysis (IPA) to identify risk factor genes. Microarray analysis showed 3272 genes regulated with a fold-change of >±1.4. IPA showed 225 genes belonging to mammary-tumor development function: 198 for CEE/MPA vs. 34 for E₂/P. Sixteen genes involved in mammary tumor inclination were subject to Q-PCR, inclining the CEE/MPA group towards an increased risk for breast carcinoma compared to the E₂/P group at a very high significance level (p = 3.1 × 10^-8, z-score 1.94). The combination of E₂/P affected breast cancer-related genes much less than CEE/MPA.

Breast Cancer Risk with Progestin Subdermal Implants: A Challenge in Patients Counseling

There is a steady global rise in the use of progestin subdermal implants, where use has increased by more than 20 times in the past two decades. BC risk has been reported with the older progestin only methods such as oral pills, injectables, and intrauterine devices, however, little is known about the risk with subdermal implants. In this review, we aim to update clinicians and researchers on the current evidence to support patient counseling and to inform future research directions. The available evidence of the association between the use of progestin subdermal implants and BC risk is discussed. We provide an overview of the potential role of endogenous progesterone in BC development. The chemical structure and molecular targets of synthetic progestins of relevance are summarized together with the preclinical and clinical evidence on their association with BC risk. We review all studies that investigated the action of the specific progestins included in subdermal implants. As well, we discuss the potential effect of the use of subdermal implants in women at increased BC risk, including carriers of BC susceptibility genetic mutations.

Progestogen addition with low-dose levonorgestrel intrauterine system in menopausal hormone treatment gives less normal breast tissue proliferation than oral norethisterone acetate or medroxyprogesterone acetate

Background The impact of hormones on the development of breast cancer is despite extensive studies, incompletely understood. Combined estrogen-progestogen treatment augments the risk for breast cancer beyond that of estrogen alone, according to numerous studies. The role of breast cell proliferation as a promoter in the development and growth of breast cancer is well recognized. Materials and methods Seventy-nine patients from three randomised trials were subject to a re-analysis of breast cell proliferation: (1) 22 women received continuous combined treatment with oral estradiol (E2) 2 mg/norethisterone acetate (NETA) 1 mg once daily for 3 months. (2) Thirty-seven women received 2 months of sequential treatment with oral conjugated equine estrogens (CEE) 0.625 mg daily combined with medroxyprogesterone acetate (MPA) 5 mg for 14/28 days of each cycle. (3) Twenty women received oral estradiol-valerate (E2V) 2 mg daily combined with levonorgestrel (LNG) intrauterine system (IUS), 20 μg/24 h for 2 months. Fine needle aspiration (FNA) (studies 1 and 3) and core needle biopsy (CNB) (study 2) were used for the assessment of breast cell proliferation. Results There were no baseline proliferation differences, but at the end of treatment there was a highly significant between-group difference for E2V/LNG IUS versus the other two groups (p = 0.0025). E2/NETA and CEE treatments gave a 4-7-old increase in proliferation during treatment (p = 0.04) and (p = 0.007), respectively, which was absent in the E2V/LNG group, showing a significant correlation with insulin-like growth factor binding protein-3 (IGFBP-3) serum levels. Conclusion E2V in combination with very low serum concentrations of LNG in the IUS gives no increase in proliferation in the normal breast.

Effects of drospirenone and norethisterone acetate combined with estradiol on mammographic density and proliferation of breast epithelial cells-A prospective randomized trial

OBJECTIVE

There are no previous data on the influence of drospirenone (DRSP) in combination with estradiol (E2) on the breast in postmenopausal women. The objective of this study was to evaluate the effect of DRSP or norethisterone acetate (NETA) in continuous combination with E2 on two surrogate markers for breast cancer - mammographic breast density and proliferation of breast epithelial cells - in healthy postmenopausal women.

STUDY DESIGN

120 healthy, naturally postmenopausal women were randomized to either 2 mg of DRSP or 0.5 mg of NETA in continuous combination with 1 mg of oral E2. The women underwent mammography and fine-needle aspiration biopsy of the breast at baseline and after six months of treatment.

MAIN OUTCOME MEASURES

Digitized mammographic breast density and breast cell proliferation.

RESULTS

There was a significant increase in mammographic breast density after treatment in both groups (median increase 5.5% for E2/DRSP and 2.3% for E2/NETA, respectively, p < 0.001), but with no significant difference between groups. The proliferation of breast epithelial cells also increased in both groups (p < 0.001, respectively), with a significantly larger increase in the E2/DRSP group than in the E2/NETA group (2.5% versus 0.7%, respectively, p < 0.05). Systolic blood pressure had decreased significantly after 6 months of treatment in the E2/DRSP group (p < 0.05) but not in the E2/NETA group.

CONCLUSIONS

Breast density increased to a similar degree with E2/DRSP and E2/NETA. Proliferation of breast epithelial cells also increased significantly in both groups but was slightly more pronounced in the E2/DRSP group.

Dehydroepiandrosterone and/or its metabolites: possible androgen receptor antagonistic effects on digitized mammographic breast density in normal breast tissue of postmenopausal women

Background Androgens, notably testosterone inhibit breast cell proliferation and negative correlations between free testosterone (fT) and breast cell proliferation as well as mammographic density have been described. Dehydroepiandrosterone (DHEA) is reported to be a partial androgen antagonist in breast tumor cells in vitro. Our aim was to investigate if circulating DHEA had any effects on the association between circulating fT and mammographic density in vivo in the normal postmenopausal breast. Methods We measured visual and digitized mammographic density and serum DHEA, testosterone, sex-hormone-binding globulin and calculated fT in 84 healthy untreated postmenopausal women. Results Significant negative correlations between fT and both visual and digitized mammographic density were strengthened when the median DHEA level decreased from 10.2 to 8.6 nmol/L. Thereafter, correlations became weaker again probably due to decreasing fT levels and/or sample size. There were no correlations between mammographic density and DHEA, at any of the DHEA concentration ranges studied. Serum levels of fT and DHEA were positively correlated. Conclusion Our findings demonstrate that circulating DHEA and/or its metabolites counteract the inhibitory action of fT on mammographic breast density.

Estrone - a partial estradiol antagonist in the normal breast

Oral hormone replacement therapy (HRT) based on estradiol-17β (E2) greatly increases circulating estrone (E1) levels. E1 is an estrogen receptor agonist but may also be a partial E2 antagonist. We investigated the effects of circulating E1 on the association between circulating E2 and the increase in mammographic density (∂MD) in 46 healthy post-menopausal women treated with E2 2 mg and norethisterone acetate 1 mg daily. MD and serum E1 and E2 were measured before and after 6 months of treatment. At high E1 levels, ∂MD showed significant positive correlations leading to increase (∂-values) in both E1 and E2. Lowering the upper serum E1 limit strengthened the correlations to ∂E2 while the significant correlations to ∂E1 disappeared. E1 at high concentrations may act as a partial E2 antagonist also in the normal breast in vivo and disturb relationships between circulating E2 and biological estrogen effects. When investigating the relations between circulating steroids and their effects, structurally related compounds, which may act as partial antagonists, have to be considered, at least when they are present in higher concentrations.

Perspective on hormone therapy 10 years after the WHI

The Women's Health Initiative (WHI) hormone trials are among the most influential and debated research studies in women's health in recent medical history. This year (2013) marked the 10th anniversary of the publication of the WHI results and this past decade has been nothing less than revolutionary. We have witnessed a transformative evolution in our understanding of, and in the practice of, menopause management and herein summarize the strides the field has traversed over the past 10 years.

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.

Mechanisms for differential effects between natural progesterone and synthetic progestogens on normal breast tissue

Both epidemiological studies and experimental data on normal breast tissue suggest increased cancer risk, proliferation and mammographic breast density (MD) during hormone therapy (HT) containing synthetic progestogens in traditional doses, and the relative risk or RR is approximately 1.5–3 (for women treated vs. untreated with the above therapies), proliferation levels of normal breast epithelial cells of around 10% and increase in MD in up to around 50% of women during treatment. Dose-response relationships have been inferred by correlations between progestogens as levonorgestrel, norethisterone acetate and medroxyprogesterone acetate on the one hand and proliferation and/or MD on the other hand, and of indications of lower relative risk of breast cancer with modern low or ultra-low dose HT. In contrast, natural progesterone endogenously during the menstrual cycle has a weak effect and exogenous estrogen in combination with oral micronized progesterone in HT has shown to yield an indifferent effect on proliferation. Furthermore, in epidemiological studies such as the French E3N cohort, these combinations have not shown any risk increase for breast cancer for at least 5 years of treatment. Experimental data supporting or not supporting the view that the main proliferative mechanism for natural progesterone is through binding to its nascent progesterone receptors is discussed as well as the pros and cons that the non-physiological higher proliferation levels induced by synthetic progestogens is mainly mediated through interaction with potent growth factors and their paracrine and/or cell signaling pathways.

Testosterone addition during menopausal hormone therapy: effects on mammographic breast density

OBJECTIVE

To study the effect on mammographic breast density of testosterone addition during combined estrogen/progestogen therapy in postmenopausal women.

METHODS

A prospective, randomized, double-blind, placebo-controlled trial. A total of 99 women were given 2 mg 17beta-estradiol and 1 mg norethisterone acetate in combination with either a testosterone patch (300 mug/24 h) or a placebo patch. Mammographic breast density at baseline and after 6 months was assessed by visual classification scales and by digitized quantification. A standardized questionnaire was used to quantify subjective breast symptoms.

RESULTS

Visual classifications showed an increase in mammographic density in 18-30% of the women, with no significant differences between the treatment groups. The mean increase of the area of dense breast during treatment according to digitized assessment was 7.4% in the placebo group and 5.4% in the testosterone group. Breast symptoms showed a positive association with the increase in density (r(s) = 0.34; p < 0.01). Symptoms were most pronounced at 2 months of treatment. Density, both at baseline (r(s) = -0.35; p < 0.01) and change during treatment (r(s) = -0.28; p < 0.01) showed a negative association with free testosterone levels.

CONCLUSION

The addition of testosterone does not appear to influence mammographic breast density in women concurrently treated with a common oral estrogen/progestogen regimen for a period of 6 months.

Expression of syndecan-1 in histologically normal breast tissue from postmenopausal women with breast cancer according to mammographic density

OBJECTIVE

To analyze the expression of Syndecan-1 in dense and non-dense human breast tissue.

METHODS

Specimens of histologically normal tissue were obtained from postmenopausal women undergoing surgery for breast cancer. Each tissue block was subject to radiological examination and pair-wise samples of dense and non-dense tissue were collected. Semi-quantitative assessment of immunohistochemical staining intensity for Syndecan-1 and estrogen receptor subtypes was performed.

RESULTS

The expression of Syndecan-1 in all tissue compartments was significantly higher in dense than in non-dense specimens. The strongest staining was recorded in stromal tissue. There was a strong correlation between epithelial estrogen receptor alpha and stromal cell Syndecan-1 expression in dense tissue (rs = 0.7; p = 0.02). This association was absent in non-dense tissue.

CONCLUSION

An increase of Syndecan-1 in all tissue compartments and a redistribution from epithelium to stroma may be a characteristic feature for dense breast tissue.

Neutral effect of ultra-low-dose continuous combined estradiol and norethisterone acetate on mammographic breast density

OBJECTIVE

To compare the effects of two different ultra-low doses of continuous combined hormone therapy and placebo on mammographic breast density in postmenopausal women.

METHODS

A subpopulation of 255 postmenopausal women from the CHOICE trial were randomly assigned to 0.5 mg 17beta-estradiol (E2) + 0.25 mg norethisterone acetate (NETA), 0.5 mg E2 + 0.1 mg NETA, or placebo. Women using hormone replacement therapy (HRT) up to 2 months prior to the study were excluded; 154 women fulfilled the inclusion criteria. Mammograms were performed at baseline and after 6 months. Breast density was evaluated by visual classification scales and a computer-assisted digitized technique.

RESULTS

No significant differences were detected between the active treatment groups and the placebo group in the digitized quantification. The mean baseline values for density around 20% were unchanged after 6 months. Also, visual classifications showed no increase in breast density in any study group.

CONCLUSION

In contrast to currently available bleed-free regimens, the new ultra-low-dose combination of 0.5 mg E2 and 0.1 mg NETA seems to have very little or even a neutral effect on the breast. Both digitized quantification and visual assessment of breast density were unchanged after 6 months. Larger prospective studies should be performed to confirm this new finding.

[Hormones and mammographic breast density]

Breast constitutional density may be altered and increased (acquired density) by hormonal interventions such as hormone replacement therapy (HRT). The effects of endogenous (steroids, prolactin, insulin-like factors...) and exogenous (HRT, levonorgestrel IUD, tibolone, tamoxifen, SERMs) hormones will be reviewed. Continuous combined estrogen-progestin preparations are most likely to cause an increase in density. Estrogen alone and tibolone are less likely to cause an increase in density. The sensitivity and specificity of mammography are decreased, with increased risk of interval carcinoma and rate of short interval follow-up from false positive results. The issue with regards to interruption of the hormonal therapy prior to mammography, and the duration of the interruption, are discussed.

Breast cancer and hormonal therapy

Valid evidence from randomized-controlled trials indicates that breast cancer risk is increased with combined estrogen/progestogen use and that such treatment implies a risk greater than that of estrogen alone. Overall, risk estimates from observational studies are somewhat higher than in randomized-controlled trials but remain modest as compared with other risk factors even after long-term treatment. For combined estrogen/progestogen therapy, risk increases gradually to reach statistical significance after 4 to 5 years. Apart from its many beneficial health effects, the safety data for use of estrogen alone are quite reassuring. The only justifications for progestogen addition are for bleeding control and endometrial protection. At present, there are several new therapeutic compounds and concepts in development, which hold promise to provide both endometrial protection and breast safety.

Associations between serum testosterone levels, cell proliferation and progesterone receptor content in normal and malignant breast tissue in postmenopausal women

Progestogens and progesterone receptors (PR) may play an important role in increased breast proliferation following combined estrogen/progestogen hormone therapy, while androgens may counteract this effect. In 50 untreated healthy postmenopausal women and 48 untreated postmenopausal breast cancer patients, we measured serum levels of testosterone (T), sex hormone-binding globulin (SHBG), estrone (E(1)) and adrenal androgens; and additionally, in the breast cancer patients, cortisol and corticosteroid-binding globulin and endocrine data related to breast proliferation (assessed using the Ki-67/MIB-1 monoclonal antibody) and PR levels (determined by enzyme immunoassay) in the breast cancer tissue. In the healthy women the percentage of MIB-1(+) cells showed significant negative correlations with serum levels of total T, calculated free T (fT) and the fT/E(1) ratio; while in the breast cancer patients PR content showed significant negative correlations with fT level, the fT/E(1) ratio and the T/SHBG ratio. No other correlations were found in any of the groups. Our findings in healthy women confirm previous reports of an antiproliferative effect of androgens in breast tissue and our finding in breast cancer patients suggests that this antiproliferative effect may be mediated via downregulation of PR.

Is HRT justified for symptom management in women at higher risk of developing breast cancer?

Hormone replacement therapy (HRT) is the most efficacious intervention for the treatment of estrogen-deficiency symptoms. Prescriptions for HRT have fallen over the last 3 years due to anxiety provoked about breast cancer risk and recurrence that has been generated by recent clinical trials. In women at population risk of breast cancer, these trials have not shown risks greater than estimates from clinical trial evidence that predated them. For women at increased breast cancer risk due to a family history or high-risk benign breast conditions, clinical trial data are limited but suggest a lack of an additive effect of HRT on risk. In symptomatic breast cancer survivors, observational data suggest no increase in recurrence but these data are open to bias. Interim analyses of large, randomized trials have shown contradictory outcomes and, as a result, three large HRT randomized trials have now been closed. The randomized LIBERATE trial evaluating tibolone in breast cancer survivors is fully recruited and continuing. The current clinical climate is 'HRT adverse' but, due to a lack of effective alternatives for symptom relief, women at higher breast cancer risk and breast cancer survivors are still requesting information about HRT. In this situation, discussion of the current clinical uncertainty surrounding the use of HRT must be undertaken to ensure that women are adequately informed.

Levonorgestrel-releasing intrauterine system as an adjunct to estrogen for the treatment of menopausal symptoms-a review

Exogenous estrogen is an effective means of prevention for postmenopausal symptoms. Estrogen treatment should be combined with progesterone in non-hysterectomized women to prevent estrogen-induced malignant transformation of the endometrium. Progesterone supplementation using continuous combined estrogen + progesterone treatment may result in an increased incidence of breast cancer and cardiovascular disease. In addition, progesterone supplementation with sequential estrogen + progesterone treatment may cause immediate adverse effects, such as irregular bleeding and spotting, breast congestion, fluid retention, abdominal distention, and a change in lipid profile. All these effects are related, at least in part, to the progesterone component of the therapy.To avoid these complications, researchers are seeking safer progestational components and different modes of administration. In this article we review the findings on the use of the novel levonorgestrel-releasing intrauterine system as a therapeutic tool for localized, rather than systemic, progesterone administration in postmenopausal women.

Testosterone inhibits estrogen/progestogen-induced breast cell proliferation in postmenopausal women

OBJECTIVE

During the past few years serious concern has been raised about the safety of combined estrogen/progestogen hormone therapy, in particular about its effects on the breast. Several observations suggest that androgens may counteract the proliferative effects of estrogen and progestogen in the mammary gland. Thus, we aimed to study the effects of testosterone addition on breast cell proliferation during postmenopausal estrogen/progestogen therapy.

DESIGN

We conducted a 6-month prospective, randomized, double-blind, placebo-controlled study. A total of 99 postmenopausal women were given continuous combined estradiol 2 mg/norethisterone acetate 1 mg and were equally randomly assigned to receive additional treatment with either a testosterone patch releasing 300 microg/24 hours or a placebo patch. Breast cells were collected by fine needle aspiration biopsy at baseline and after 6 months, and the main outcome measure was the percentage of proliferating breast cells positively stained by the Ki-67/MIB-1 antibody.

RESULTS

A total of 88 women, 47 receiving active treatment and 41 in the placebo group, completed the study. In the placebo group there was a more than fivefold increase (P<0.001) in total breast cell proliferation from baseline (median 1.1%) to 6 months (median 6.2%). During testosterone addition, no significant increase was recorded (1.6% vs 2.0%). The different effects of the two treatments were apparent in both epithelial and stromal cells.

CONCLUSIONS

Addition of testosterone may counteract breast cell proliferation as induced by estrogen/progestogen therapy in postmenopausal women.

Breast response to menopausal hormone therapy--aspects on proliferation, apoptosis and mammographic density

Breast cancer is the major malignancy among women in the Western world. The breast is clearly a target organ for sex steroid hormones and hormonal treatments have been associated with an increased risk of breast cancer. The balance between proliferation and apoptosis is important for breast cell homeostasis. Mammographic breast density has been identified as a strong and independent risk factor for breast cancer. It seems clear that there is a difference between various hormonal treatments with regard to their effects on breast density and cell proliferation. Also, not all women respond similarly to the same treatment. Combined estrogen and progestogen therapy generally will enhance density and proliferation more than treatment with estrogen alone. Certain constitutional and hormonal factors appear to be predictive of breast reactivity. Older women with a low body mass index respond more strongly to treatment. Estrogen levels have a positive and androgens a negative association to increase in density and proliferation. A combination of increased proliferation and decreased apoptosis could be one mechanism to explain the excess risk of breast cancer during combined estrogen/progestogen treatment. Tibolone seems to have less impact on breast response than conventional hormone therapy. Efforts should be made to identify those women with an adverse response to treatment as well as therapeutic principles with the least possible influence on the breast.