The National Cancer Institute of Canada Clinical Trials Group MAP.3 trial: an international breast cancer prevention trial

Hormone therapy in women with benign breast disease - What little is known and suggestions for clinical implementation

Benign breast disease encompasses a spectrum of lesions within the breast. While some lesions pose no increase in risk, others may elevate the likelihood of developing breast cancer by four- to five-fold. This necessitates a personalized approach to screening and lifestyle optimization for women. The menopausal transition is a critical time for the development of benign breast lesions. Increased detection can be attributed to the heightened precision and utilization of screening mammography, with or without the use of supplemental imaging. While it is widely acknowledged that combined hormone therapy involving estrogen and progesterone may elevate the risk of breast cancer, data from the Women's Health Initiative (WHI) indicates that estrogen-alone therapies may actually reduce the overall risk of cancer. Despite this general understanding, there is a notable gap in information regarding the impact of hormone therapy on the risk profile of women with specific benign breast lesions. This review comprehensively examines various benign breast lesions, delving into their pathophysiology and management. The goal is to enhance our understanding of when and how to judiciously prescribe hormone therapy, particularly in the context of specific benign breast conditions. By bridging this knowledge gap, the review provides valuable insights into optimizing healthcare strategies for women with benign breast disease, and offers a foundation for more informed decision-making regarding hormone therapy.

Reassessing the Benefits and Harms of Risk-Reducing Medication Considering the Persistent Risk of Breast Cancer Mortality in Estrogen Receptor-Positive Breast Cancer

PURPOSE

Recent studies, including a meta-analysis of 88 trials, have shown higher than expected rates of recurrence and death in hormone receptor-positive breast cancer. These new findings suggest a need to re-evaluate the use of risk-reducing medication to avoid invasive breast cancer and breast cancer death in high-risk women.

METHODS

We adapted an established Cancer Intervention and Surveillance Modeling Network model to evaluate the lifetime benefits and harms of risk-reducing medication in women with a ≥ 3% 5-year risk of developing breast cancer according to the Breast Cancer Surveillance Consortium risk calculator. Model input parameters were derived from meta-analyses, clinical trials, and large observational data. We evaluated the effects of 5 years of risk-reducing medication (tamoxifen/aromatase inhibitors) with annual screening mammography ± magnetic resonance imaging (MRI) compared with no screening, MRI, or risk-reducing medication. The modeled outcomes included invasive breast cancer, breast cancer death, side effects, false positives, and overdiagnosis. We conducted subgroup analyses for individual risk factors such as age, family history, and prior biopsy.

RESULTS

Risk-reducing tamoxifen with annual screening (± MRI) decreased the risk of invasive breast cancer by 40% and breast cancer death by 57%, compared with no tamoxifen or screening. This is equivalent to an absolute reduction of 95 invasive breast cancers, and 42 breast cancer deaths per 1,000 high-risk women. However, these drugs are associated with side effects. For example, tamoxifen could increase the number of endometrial cancers up to 11 per 1,000 high-risk women. Benefits and harms varied by individual characteristics.

CONCLUSION

The addition of risk-reducing medication to screening could further decrease the risk of breast cancer death. Clinical guidelines for high-risk women should consider integrating shared decision making for risk-reducing medication and screening on the basis of individual risk factors.

Awareness and current knowledge of breast cancer

Breast cancer remains a worldwide public health dilemma and is currently the most common tumour in the globe. Awareness of breast cancer, public attentiveness, and advancement in breast imaging has made a positive impact on recognition and screening of breast cancer. Breast cancer is life-threatening disease in females and the leading cause of mortality among women population. For the previous two decades, studies related to the breast cancer has guided to astonishing advancement in our understanding of the breast cancer, resulting in further proficient treatments. Amongst all the malignant diseases, breast cancer is considered as one of the leading cause of death in post menopausal women accounting for 23% of all cancer deaths. It is a global issue now, but still it is diagnosed in their advanced stages due to the negligence of women regarding the self inspection and clinical examination of the breast. This review addresses anatomy of the breast, risk factors, epidemiology of breast cancer, pathogenesis of breast cancer, stages of breast cancer, diagnostic investigations and treatment including chemotherapy, surgery, targeted therapies, hormone replacement therapy, radiation therapy, complementary therapies, gene therapy and stem-cell therapy etc for breast cancer.

A review of clinical aspects of breast cancer

Breast cancer is the most frequently diagnosed cancer in women and ranks second among causes for cancer related death in women. The ability to identify and diagnose breast cancer has improved markedly. Treatment decisions which were based in the past predominantly on the anatomic extent of the disease are shifting to the underlying biological mechanisms. Gene array technology has led to the recognition that breast cancer is a heterogeneous disease composed of different biological subtypes, and genetic profiling enables response to chemotherapy to be predicted. Breast conservation became an established standard of care and the oncoplastic approach enables wide excisions without compromising the natural shape of the breast. Sentinel lymph node biopsy has replaced axillary dissection as the standard procedure to stage the axilla and spared many patients the excess morbidity of axillary dissection. Targeted therapy to the oestrogen receptor plays a major role in systemic therapy; pathways responsible for endocrine resistance have been targeted as well. Biological therapy has been developed to target HER2 receptor and combination of antibody drug conjugates linked cytotoxic therapy to HER2 antibodies. Meaningful improvements in survival resulted from the new effective systemic agents and patients with metastasis are likely to have a longer survival.

GPER Function in Breast Cancer: An Overview

The G-protein-coupled estrogen receptor-1 (GPER, formerly known as GPR30) has attracted increasing interest, considering its ability to mediate estrogenic signaling in different cell types, including the hormone-sensitive tumors like breast cancer. As observed for other GPCR-mediated responses, the activation of the epidermal growth factor receptor is a fundamental integration point in the biological action triggered by GPER. A wide number of natural and synthetic compounds, including estrogens and anti-estrogens, elicit stimulatory effects in breast cancer through GPER up-regulation and activation, suggesting that GPER function is associated with breast tumor progression and tamoxifen resistance. GPER has also been proposed as a candidate biomarker in triple-negative breast cancer, opening a novel scenario for a more comprehensive assessment of breast tumor patients.

Targeted therapy for breast cancer prevention

With a better understanding of the etiology of breast cancer, molecularly targeted drugs have been developed and are being testing for the treatment and prevention of breast cancer. Targeted drugs that inhibit the estrogen receptor (ER) or estrogen-activated pathways include the selective ER modulators (tamoxifen, raloxifene, and lasofoxifene) and aromatase inhibitors (AIs) (anastrozole, letrozole, and exemestane) have been tested in preclinical and clinical studies. Tamoxifen and raloxifene have been shown to reduce the risk of breast cancer and promising results of AIs in breast cancer trials, suggest that AIs might be even more effective in the prevention of ER-positive breast cancer. However, these agents only prevent ER-positive breast cancer. Therefore, current research is focused on identifying preventive therapies for other forms of breast cancer such as human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancer (TNBC, breast cancer that does express ER, progesterone receptor, or HER2). HER2-positive breast cancers are currently treated with anti-HER2 therapies including trastuzumab and lapatinib, and preclinical and clinical studies are now being conducted to test these drugs for the prevention of HER2-positive breast cancers. Several promising agents currently being tested in cancer prevention trials for the prevention of TNBC include poly(ADP-ribose) polymerase inhibitors, vitamin D, and rexinoids, both of which activate nuclear hormone receptors (the vitamin D and retinoid X receptors). This review discusses currently used breast cancer preventive drugs, and describes the progress of research striving to identify and develop more effective preventive agents for all forms of breast cancer.

Establishing a program for individuals at high risk for breast cancer

Our need to create a program for individuals at high risk for breast cancer development led us to research the available data on such programs. In this paper, we summarize our findings and our thinking process as we developed our own program. Breast cancer incidence is increasing worldwide. Even though there are known risk factors for breast cancer development, approximately 60% of patients with breast cancer have no known risk factor, although this situation will probably change with further research, especially in genetics. For patients with risk factors based on personal or family history, different models are available for assessing and quantifying risk. Assignment of risk levels permits tailored screening and risk reduction strategies. Potential benefits of specialized programs for women with high breast cancer risk include more cost -effective interventions as a result of patient stratification on the basis of risk; generation of valuable data to advance science; and differentiation of breast programs from other breast cancer units, which can result in increased revenue that can be directed to further improvements in patient care. Guidelines for care of patients at high risk for breast cancer are available from various groups. However, running a high-risk breast program involves much more than applying a guideline. Each high-risk program needs to be designed by its institution with consideration of local resources and country legislation, especially related to genetic issues. Development of a successful high-risk program includes identifying strengths, weaknesses, opportunities, and threats; developing a promotion plan; choosing a risk assessment tool; defining "high risk"; and planning screening and risk reduction strategies for the specific population served by the program. The information in this article may be useful for other institutions considering creation of programs for patients with high breast cancer risk.

Exemestane: one part of the chemopreventive spectrum for ER-positive breast cancer

Development of drugs to prevent breast cancer has focused largely on anti-estrogenic agents, leading to approval by the US FDA of two such agents for this purpose: tamoxifen and raloxifene. However, the uptake of these drugs by high-risk women and their primary care physicians has been limited, due in large part to a perceived unfavorable risk:benefit balance. The current focus is on aromatase inhibitors, which appear to have more acceptable side effects in addition to being more efficacious in reducing breast cancer risk in high-risk women. The placebo-controlled phase III MAP.3 trial tested the AI exemestane in high-risk women and documented a 65% relative reduction in total and a 73% reduction in ER-positive breast cancers in the intervention compared to the placebo group. Toxicities centered around musculoskeletal side effects, but in the relatively short 35-month median follow-up period, these did not impair quality-of-life. A bone study nested within MAP.3 demonstrated significant decreases in bone mineral density (BMD) and in structural parameters of bone quality. The strengths and weaknesses of preventive exemestane as evaluated in the MAP.3 trial are discussed as are relevant areas for future consideration: influence of obesity, alternative dosing, and biomarker use in phase III prevention trials of aromatase inhibitors.

Exemestane for breast cancer prevention: a critical shift?

The Mammary Prevention 3 (MAP.3) placebo-controlled randomized trial in 4,560 high-risk postmenopausal women showed a 65% reduction in invasive breast cancer with the use of exemestane at 35 months median follow-up. Few differences in adverse events were observed between the arms, suggesting a promising risk:benefit balance with exemestane for use in chemoprevention. Yet, the MAP.3 design and implementation raise concerns regarding limited data maturity and not prospectively including key bone-related and other toxicities as study end points. Exemestane for prevention is juxtaposed against selective estrogen receptor modulators and the other aromatase inhibitors. Additional issues for prevention, including the influence of obesity, alternative dosing, and biomarker use in phase III trials, are addressed.

SIGNIFICANCE

The recently completed MAP.3 trial of exemestane for breast cancer prevention offers a potential new standard for pharmaceutical risk reduction in high-risk postmenopausal women. In addition to describing key findings from the publication of MAP.3 and related trials, our review undertakes a detailed analysis of the strengths and weaknesses of MAP.3 as well as the implications for future prevention research.

Chemoprevention of Breast Cancer: The Paradox of Evidence versus Advocacy Inaction

Women who are at high risk of breast cancer can be offered chemoprevention. Chemoprevention strategies have expanded over the past decade and include selective receptor modulator inhibitors and aromatase inhibitors. Physicians are expected to provide individualized risk assessments to identify high risk women who may be eligible for chemoprevention. It is prudent that physicians utilize a shared decision approach when counseling high risk women about their preventive options. Barriers and misperceptions however exist with patient and physician acceptance of chemoprevention and continue to impede uptake of chemoprevention as a strategy to reduce breast cancer risk. Programs to increase awareness and elucidate the barriers are critical for women to engage in cancer prevention and promote chemoprevention adherence.

Chemoprevention for breast cancer

Despite the progress that has been made in breast cancer diagnosis and treatment, this disease is still a major health problem, being the most frequently diagnosed cancer and the first leading cause of cancer death among women both in developed and economically developing countries. In some developed countries incidence rate start to decrease from the end of last millennium and this can be explained, at least in part, by the decrease in hormone replacement therapy use by post-menopausal women. Chemoprevention has the potential to be an approach of utmost importance to reduce cancer burden at least among high-risk populations. Tamoxifen and raloxifene are both indicated for the prevention of breast cancer in women at high risk for the development of the disease, although raloxifene may have a more favorable adverse-effect profile, causing fewer uterine cancers and thromboembolic events. Aromatase inhibitors will most probably become an additional prevention treatment option in the near future, in view of the promising results observed in adjuvant trials and the interesting results of the very recently published first chemoprevention trial using an aromatase inhibitor.(2) Despite impressive results in most clinical trials performed to date, chemoprevention is still not widely used. Urgently needed are better molecular risk models to accurately identify high-risk subjects, new agents with a better risk/benefit ratio and validated biomarkers.

Tamoxifen vs Raloxifene vs Exemestane for Chemoprevention

Clinical trial data on selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) have demonstrated reduced breast cancer incidence in the prevention setting among high-risk women. We conducted an extensive review of clinical trials and recent published reports of barriers to uptake of breast cancer chemoprevention, to provide health care professionals with information to improve decision-making regarding chemoprevention. Despite the positive results of these trials, uptake of chemoprevention has been low due to barriers in identifying high-risk women, lack of understanding of risks and benefits, as well as concerns about side effects. Interventions designed to increase uptake have met with limited success. Clinicians can support women in informed decision-making about SERMs and AIs by effectively communicating breast cancer risk and enhancing knowledge about the risks and benefits of chemoprevention. Promoting uptake and adherence to chemoprevention holds promise for reducing the public health burden of this disease.

Aromatase inhibitors, estrogens and musculoskeletal pain: estrogen-dependent T-cell leukemia 1A (TCL1A) gene-mediated regulation of cytokine expression

Introduction

Arthralgias and myalgias are major side effects associated with aromatase inhibitor (AI) therapy of breast cancer. In a recent genome-wide association study, we identified SNPs - including one that created an estrogen response element near the 3' end of the T-cell leukemia 1A (TCL1A) gene - that were associated with musculoskeletal pain in women on adjuvant AI therapy for breast cancer. We also showed estrogen-dependent, SNP-modulated variation in TCL1A expression and, in preliminary experiments, showed that TCL1A could induce IL-17RA expression. In the present study, we set out to determine whether these SNPs might influence cytokine expression and effect more widely, and, if so, to explore the mechanism of TCL1A-related AI-induced side effects.

Methods

The functional genomic experiments performed included determinations of TCL1A, cytokine and cytokine receptor expression in response to estrogen treatment of U2OS cells and lymphoblastoid cell lines that had been stably transfected with estrogen receptor alpha. Changes in mRNA and protein expression after gene knockdown and overexpression were also determined, as was NF-κB transcriptional activity.

Results

Estradiol (E2) increased TCL1A expression and, in a TCL1A SNP-dependent fashion, also altered the expression of IL-17, IL-17RA, IL-12, IL-12RB2 and IL-1R2. TCL1A expression was higher in E2-treated lymphoblastoid cell lines with variant SNP genotypes, and induction of the expression of cytokine and cytokine receptor genes was mediated by TCL1A. Finally, estrogen receptor alpha blockade with ICI-182,780 in the presence of E2 resulted in greatly increased NF-κB transcriptional activity, but only in cells that carried variant SNP genotypes. These results linked variant TCL1A SNP sequences that are associated with AI-dependent musculoskeletal pain with increased E2-dependent TCL1A expression and with downstream alterations in cytokine and cytokine receptor expression as well as NF-κB transcriptional activity.

Conclusions

SNPs near the 3' terminus of TCL1A were associated with AI-dependent musculoskeletal pain. E2 induced SNP-dependent TCL1A expression, which in turn altered IL-17, IL-17RA, IL-12, IL-12RB2, and IL-1R2 expression as well as NF-κB transcriptional activity. These results provide a pharmacogenomic explanation for a clinically important adverse drug reaction as well as insights into a novel estrogen-dependent mechanism for the modulation of cytokine and cytokine receptor expression.

Management of bone disease in patients undergoing hormonal therapy for breast cancer

Estrogen deficiency at menopause is associated with increased risk of bone loss and osteoporosis. Aromatase inhibitors (AIs) are increasingly being used for the treatment of postmenopausal hormone-sensitive breast cancer because of better disease-free survival compared with tamoxifen seen in clinical trials with AIs. This article reviews the effect of endocrine therapies of breast cancer on bone and the management of bone disease with these endocrine therapies. The effect of these therapies on bone mineral density and bone turnover along with possible interventions is discussed. AIs are also associated with skeletal-related events, which are not discussed.

The impact of systemic therapy following ductal carcinoma in situ

Following local therapy for ductal carcinoma in situ (DCIS), tamoxifen reduces the risk of ipsilateral and contralateral breast cancer by 30%-50%. Studies of tamoxifen in women with resected DCIS have not shown any effect on overall or cancer-specific survival. The adverse event profile of tamoxifen is well characterized, and individual risks and benefits should be assessed to guide decision making. We review the results of the phase III trials of tamoxifen in DCIS as well as the emerging risk reduction therapies.

Nonhormonal management of hot flashes for women on risk reduction therapy

Hot flashes are very common in women in menopause and can have a detrimental effect on quality of life. Women on risk reduction therapy are particularly prone because treatments, such as tamoxifen, raloxifene, or oophorectomy, have the potential to exacerbate these symptoms. Hormonal treatments, despite the fact that they represent the most effective therapies, are not used for the treatment of hot flashes in these women because of concerns that they may increase the risk for breast cancer. As a result, several nonhormonal therapies have been tested in randomized placebo-controlled trials and shown to be effective, such as paroxetine, venlafaxine, desvenlafaxine, fluoxetine, citalopram, gabapentin, and pregabalin. In addition, several nonpharmacologic therapies have been tested with various successes. An additional consideration is how some of those drugs, especially fluoxetine and paroxetine, interact with the metabolism of tamoxifen. This article discusses these issues, and provides some recommendations regarding use of nonhormonal therapies for treating hot flashes in women on risk reduction therapy, with an emphasis on pharmacogenomic considerations.

Drug development for cancer chemoprevention: focus on molecular targets

With biomolecular evidence accumulating at an exponential rate, there will be a surge in the development of targeted cancer prevention drugs and interventions in the next decade. Promising results from clinical treatment trials identify a spectrum of targeted cancer therapies in several broad categories. These include both small molecule inhibitors of either key receptors or enzyme binding sites, as well as intravenously delivered monoclonal antibodies that block a specific binding interaction between ligands and their receptors. These targeted interventions conform to a basic translational algorithm: biomarker present, biomarker modulated, and biomarker clinically relevant. A review of solid tumor targets provides a manageable list of factors that are critical to cancer cell survival. As such, these targets represent factors that are not only clinically relevant but also may play a critical role in early tumor development prior to the evolution of frank invasive malignancy. This possibility qualifies these targets for consideration in the development of cancer prevention interventions. Among solid tumors, the treatment of breast cancer with targeted drugs has a long record benchmarked by the initial US Food and Drug Administation (FDA) approval of tamoxifen for metastatic breast cancer treatment in 1977. Since then, the list of oncology drug targets has expanded to include aromatase, androgen receptor, the epidermal growth factor receptor (EGFR) family, and others. It is not surprising that tamoxifen was the first of the modern targeted therapies to be approved for cancer risk reduction and additional approvals are anticipated. The focus of this review is the pharmacologic manipulation of targets within epithelial tumor cells and the implication of those targets for intervening to suppress and eliminate premalignant cells in human tissue. Major obstacles to prevention drug development can be addressed by attention to two important areas. One of these is the refinement of early phase prevention trials to identify drug targets in epithelial cells that are at demonstrated risk of evolving into cancer cells, ie, cells from a developmental niche in cancer ontogeny. Early results suggest that molecular risk signatures may allow the investigational identification of molecular targets in premalignant tissue, with the possibility that chemoprevention agents can be used to eliminate the risk signature. To the extent that this approach can be developed, it will allow for cancer risk reduction in a way that is analogous to the measurement of tumor response to treatment. Even with improvements in the efficiency of clinical trials that come from using molecular risk signatures, there is an ever-growing list of chemoprevention agents that are candidates for evaluation. Improved prevention drug screening methodologies are therefore needed to prioritize agents for clinical testing. In addition to drug targets located in epithelial tumor cells, another list of malignancy-associated targets could be generated by considering targets in tumor-associated stromal and endothelial cells (eg, fibroblast growth factor [FGF], vascular endothelial growth factor [VEGF]), as well as targets related to a systemic reservoir of circulating cells that can be recruited to carcinogenic influence by inflammatory factors such as nuclear factor (NF)kappaB. The complementarities of target-related processes within tumors cells, in the tumor microenvironment, and beyond suggests that there is great potential for multi-targeted approaches that may be more effective than single agents and also less prone to resistance. Additional options, related to drug dose and schedule, remain to be established. As long as multiple agents can be used in combination for optimal effect with acceptable toxicity, the co-targeting of the epithelial cell compartment along with other compartments of oncogenic activity is expected to expand the dimensions of targeted prevention and enhance the overall opportunity to eliminate precancer or cells at risk of eventually transitioning to invasive cancer.

Breast cancer prevention trials: large and small trials

Breast cancer is the most common cancer among women in the United States, with 192,870 new cases and 40,170 deaths due to this disease estimated to have occurred 2009. An emphasis on prevention has been increasing in view of a persisting high incidence of disease. Seventy percent of breast cancers are estrogen receptor (ER)-positive, and are therefore presumed to be hormone-responsive and potentially treatable or preventable by anti-estrogenic agents. To date, the large, phase III randomized controlled breast cancer prevention trials have tested and are testing only hormonal drugs designed to antagonize the carcinogenic effect of endogenous estrogen; these agents are either selective estrogen receptor modulators (SERMs) or aromatase inhibitors (AIs). The SERMs, tamoxifen and raloxifene, have been shown in these large trials to reduce the risk of ER-positive breast cancers; prevention trials of AIs are ongoing. Interest is now focusing on developing agents with a broader spectrum of preventive activity, particularly with regard to ER-negative subtypes of breast cancer. A number of phase I and II trials using tissue-derived surrogate endpoint biomarkers (SEBs) as outcomes have been implemented. These smaller trials address prevention not only of ER-negative but also ER-positive breast cancers, since approximately 50% of the latter have been shown to be resistant to the estrogen-targeting drugs used in the large trials. Issues of importance in these smaller trials include choice of agent, selection of appropriate trial participants, trial design, method of access to breast tissue in women without cancer, selection and monitoring of SEBs, and monitoring of drug toxicity.

American society of clinical oncology clinical practice guideline update on the use of pharmacologic interventions including tamoxifen, raloxifene, and aromatase inhibition for breast cancer risk reduction

PURPOSE To update the 2002 American Society of Clinical Oncology guideline on pharmacologic interventions for breast cancer (BC) risk reduction. METHODS A literature search identified relevant randomized trials published since 2002. Primary outcome of interest was BC incidence (invasive and noninvasive). Secondary outcomes included BC mortality, adverse events, and net health benefits. An expert panel reviewed the literature and developed updated consensus guidelines. Results Seventeen articles met inclusion criteria. In premenopausal women, tamoxifen for 5 years reduces the risk of BC for at least 10 years, particularly estrogen receptor (ER) -positive invasive tumors. Women < or = 50 years of age experience fewer serious side effects. Vascular and vasomotor events do not persist post-treatment across all ages. In postmenopausal women, raloxifene and tamoxifen reduce the risk of ER-positive invasive BC with equal efficacy. Raloxifene is associated with a lower risk of thromboembolic disease, benign uterine conditions, and cataracts than tamoxifen in postmenopausal women. No evidence exists establishing whether a reduction in BC risk from either agent translates into reduced BC mortality. Recommendations In women at increased risk for BC, tamoxifen (20 mg/d for 5 years) may be offered to reduce the risk of invasive ER-positive BC, with benefits for at least 10 years. In postmenopausal women, raloxifene (60 mg/d for 5 years) may also be considered. Use of aromatase inhibitors, fenretinide, or other selective estrogen receptor modulators to lower BC risk is not recommended outside of a clinical trial. Discussion of risks and benefits of preventive agents by health providers is critical to patient decision making.

The impact of aromatase inhibitors on sexual functioning: current knowledge and future research directions

There is substantial evidence supporting the adjuvant usage of aromatase inhibitors (AIs) in the treatment of postmenopausal women with early breast cancer. However, the exacerbation of postmenopausal gynaecological symptoms such as vaginal dryness and dyspareunia has been reported in several studies investigating the quality of life (QOL) of women taking AIs. If not managed appropriately, these symptoms may result in sexual dysfunction, which can in turn affect a woman's QOL. There is a paucity of comprehensive research into the prevalence, nature and management of sexual dysfunction in women who receive AIs. We have performed a comprehensive literature review of the area and have also offered future research directions, including a description of an intervention study currently underway in Australia, which aims to improve sexual dysfunction and quality of life of women with breast cancer. This review therefore addresses a very topical yet neglected area which takes into consideration the increasing use of adjuvant aromatase inhibitors in women with breast cancer and the importance of recognising and acknowledging the psychosocial impact of this treatment, in this case, sexual functioning, on this population.

Estrogen receptor modulators and down regulators: optimal use in postmenopausal women with breast cancer

Endocrine treatments have been used in breast cancer since 1896, when Beatson reported on the results of oophorectomy for advanced breast cancer. In the second half of the last century, different endocrine-based compounds were developed and, in this review, the role of the selective estrogen receptor modulators (SERMs) and selective estrogen receptor down regulators (SERDs) in the postmenopausal setting are discussed. Tamoxifen is the most investigated and most widely used representative of these agents, and has been introduced in the advanced disease, in the neoadjuvant and adjuvant setting, and for the prevention of the disease. Its role has been challenged in recent years by the introduction of third-generation aromatase inhibitors that have proven higher activities than tamoxifen with different toxicity patterns. Several other SERMs have been investigated, but none have been clearly superior to tamoxifen. SERDs act as pure estrogen antagonists and should compare favourably to tamoxifen. For the time being, they have been used in the treatment of advanced breast cancers and their role in other settings still needs investigation. The increased use of aromatase inhibitors as first-line endocrine therapy has resulted in new discussions regarding the role that tamoxifen and other SERMs or SERDs may play in breast cancer. The sequencing of endocrine therapies in hormone-sensitive breast cancer remains a very important research issue.