Clinical and endocrine data for goserelin plus anastrozole as second-line endocrine therapy for premenopausal advanced breast cancer

What Is Known about Breast Cancer in Young Women?

Breast cancer (BC) is the second leading cause of cancer-related death in women under the age of 40 years worldwide. In addition, the incidence of breast cancer in young women (BCYW) has been rising. Young women are not the focus of screening programs and BC in younger women tends to be diagnosed in more advanced stages. Such patients have worse clinical outcomes and treatment complications compared to older patients. BCYW has been associated with distinct tumour biology that confers a worse prognosis, including poor tumour differentiation, increased Ki-67 expression, and more hormone-receptor negative tumours compared to women >50 years of age. Pathogenic variants in cancer predisposition genes such as BRCA1/2 are more common in early-onset BC compared to late-onset BC. Despite all these differences, BCYW remains poorly understood with a gap in research regarding the risk factors, diagnosis, prognosis, and treatment. Age-specific clinical characteristics or outcomes data for young women are lacking, and most of the standard treatments used in this subpopulation currently are derived from older patients. More age-specific clinical data and treatment options are required. In this review, we discuss the epidemiology, clinicopathologic characteristics, outcomes, treatments, and special considerations of breast cancer in young women. We also underline future directions and highlight areas that require more attention in future studies.

Practical consensus recommendations on ovarian suppression in early breast cancer (adjuvant)

Substantial survival benefits exist for patients with early-stage breast cancer who undergo treatment with single-modality ovarian suppression, but its value is uncertain. Expert oncologist discussed to determine whether additional benefits exist with ovarian suppression plus multiple adjuvant therapy which provides a new treatment option that reduces the risk of recurrence in early breast cancer. This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at this practical consensus recommendations for the benefit of community oncologists.

Therapy Algorithms for the Diagnosis and Treatment of Patients with Early and Advanced Breast Cancer

Background

In order to offer optimal treatment approaches based on available evidence, the Commission Breast of the Working Group Gynecologic Oncology (AGO) of the German Cancer Society developed therapy algorithms for eight complex treatment situations in primary and advanced breast cancer.

Summary

Therapy algorithms for the following complex treatment situations are outlined in this paper: (neo)adjuvant therapy of human epidermal growth factor receptor 2 (HER2)-positive breast cancer; axillary surgery and neoadjuvant chemotherapy; adjuvant endocrine therapy in premenopausal patients; adjuvant endocrine therapy in postmenopausal patients; hormone receptor (HR)-positive/HER2-negative metastatic breast cancer: strategies; HR-positive/HER2-negative metastatic breast cancer: endocrine-based first-line treatment; HER2-positive metastatic breast cancer: first to third-line; metastatic triple-negative breast cancer.

Key Messages

The therapy options shown in these algorithms are based on the current AGO recommendations updated in January 2020 but cannot represent all evidence-based treatment options. Prior therapies, performance status, comorbidities, patient preference, etc. must be taken into account for the actual treatment choice. Therefore, in individual cases, other evidence-based treatment options not listed here may also be appropriate and justified.

Consideration of breast cancer subtype in targeting the androgen receptor

The androgen receptor (AR) is a drug target in breast cancer, and AR-targeted therapies have induced tumor responses in breast cancer patients. In this review, we summarized the role of AR in breast cancer based on preclinical and clinical data. Response to AR-targeted therapies in unselected breast cancer populations is relatively low. Preclinical and clinical data show that AR antagonists might have a role in estrogen receptor (ER)-negative/AR-positive tumors. The prognostic value of AR for patients remains uncertain due to the use of various antibodies and cut-off values for immunohistochemical assessment. To get more insight into the role of AR in breast cancer, we additionally performed a retrospective pooled analysis to determine the prognostic value of the AR using mRNA profiles of 7270 primary breast tumors. Our analysis shows that a higher AR mRNA level is associated with improved disease outcome in patients with ER-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, but with worse disease outcome in HER2-positive subgroups. In conclusion, next to AR expression, incorporation of additional tumor characteristics will potentially make AR targeting a more valuable therapeutic strategy in breast cancer.

Sex hormones and stroke: Beyond estrogens

Stroke risk and poor stroke outcomes in postmenopausal women have usually beeen attributed to decreased levels of estrogen. However, two lines of evidence suggest that this hormone may not be solely responsible for elevated stroke risk in this population. First, the increased risk for CVD and stroke occurs much earlier than menopause at a time when estrogen levels are not yet reduced. Second, estrogen therapy has not successfully reduced stroke risk in all studies. Other sex hormones may therefore also contribute to stroke risk. Prior to menopause, levels of the gonadotrophin Follicle Stimulating Hormone (FSH) are elevated while levels of the gonadal peptide inhibin are lowered, indicating an overall decrease in ovarian reserve. Similarly, reduced estrogen levels at menopause significantly increase the ratio of androgens to estrogens. In view of the evidence that androgens may be unfavorable for CVD and stroke, this elevated ratio of testosterone to estrogen may also contribute to the postmenopause-associated stroke risk. This review synthesizes evidence from different clinical populations including natural menopause, surgical menopause, women on chemotherapy, and preclinical stroke models to dissect the role of ovarian hormones and stroke risk and outcomes.

Endocrine Therapy for Breast Cancer: A Model of Hormonal Manipulation

Oestrogen receptor (ER) is the driving transcription factor in 70% of breast cancer. Endocrine therapies targeting the ER represent one of the most successful anticancer strategies to date. In the clinic, novel targeted agents are now being exploited in combination with established endocrine therapies to maximise efficacy. However, clinicians must balance this gain against the risk to patients of increased side effects with combination therapies. This article provides a succinct outline of the principles of hormonal manipulation in breast cancer, alongside the key evidence that underpins current clinical practice. As the role of endocrine therapy in breast cancer continues to expand, the challenge is to interpret the data and select the optimal strategy for a given clinical scenario.

Endocrine Therapy in Premenopausal Hormone Receptor Positive/Human Epidermal Growth Receptor 2 Negative Metastatic Breast Cancer: Between Guidelines and Literature

There is growing interest in the endocrine treatment (ET) of premenopausal women with hormone receptor positive (HR+) metastatic breast cancer (MBC). This review summarizes available data on endocrine therapy for this patient subset and aims to define the most appropriate treatment approach. The combination of luteinizing hormone-releasing hormone (LHRH) agonists plus tamoxifen seems effective and safe and is considered as being superior to either approach alone; still, single-agent therapy remains an acceptable treatment option. Due to their mechanism of action, aromatase inhibitors alone are not suitable for the treatment of premenopausal patients, but the combination with LHRH agonists may result in excellent disease control. Fulvestrant, in conjunction with LHRH agonists, also yields interesting results regarding clinical benefit rate and time to progression; currently, other orally available selective estrogen receptor downregulators are under clinical evaluation. Recently, targeted drugs have been added to ET in order to reverse endocrine resistance, but only limited information regarding their activity in premenopausal patients is available. The cyclin dependent kinase 4 and 6 inhibitor palbociclib when combined with fulvestrant and LHRH agonists was shown to prolong progression-free survival over endocrine therapy alone in pretreated patients; similar results were obtained with the addition of abemacicilib or ribociclib to endocrine therapy. Currently, activity of the mammalian target of rapamycin inhibitor everolimus in combination with letrozole and goserelin is under assessment in premenopausal patients after progression on tamoxifen (MIRACLE trial).

IMPLICATIONS FOR PRACTICE

This review provides clinicians with an overview on the available data regarding endocrine treatment of hormone receptor positive (HR+) metastatic breast cancer (MBC) in premenopausal women and summarizes the treatment options available in routine clinical practice. Knowledge of an up-to-date therapeutic approach in women with premenopausal HR+ MBC will lead to better disease management, thereby improving disease control and quality of life while minimizing side effects.

Targeted Therapy for Premenopausal Women with HR+, HER2- Advanced Breast Cancer: Focus on Special Considerations and Latest Advances

The incidence of advanced breast cancer in premenopausal women is increasing, and breast cancer in younger women is often more aggressive and has a worse prognosis compared with breast cancer in older women. Premenopausal women with hormone receptor-positive (HR⁺) breast cancer are frequently under-represented in clinical trials, and treatment strategies in the premenopausal setting are usually extrapolated from data from postmenopausal patients, with the addition of ovarian function suppression to endocrine therapy in HR⁺ disease. However, the underlying biology of breast cancer in premenopausal women can be different from postmenopausal women, and treatment strategies should ideally be specifically tested in premenopausal patients. Recent phase III trials have now investigated cyclin-dependent kinase 4/6 (CDK4/6) inhibitors in premenopausal patients with HR⁺, HER2^- advanced breast cancer: Palbociclib and abemaciclib have been tested in a subset of premenopausal patients in the PALOMA-3 and MONARCH-2 studies, and ribociclib has been tested in the phase III MONALEESA-7 trial, which was entirely dedicated to premenopausal women. This comprehensive review summarizes the differences in the biology of HR⁺, HER2^- breast cancer in the premenopausal population compared with the postmenopausal population; discusses special considerations for treatment of premenopausal women; and reviews the evidence from clinical trials investigating endocrine therapy, other targeted treatments, and ovarian function suppression in the HR⁺, HER2^- advanced breast cancer setting. Clin Cancer Res; 24(21); 5206-18. ©2018 AACR.

Aromatase inhibitors in premenopausal women with breast cancer: the state of the art and future prospects

Approximately 11% of patients with breast cancer (bca) are diagnosed before menopause, and because in most of those patients the tumour expresses a hormone receptor, treatment with endocrine interventions can be applied in any setting of disease (early or advanced). In the past, hormonal treatment consisted only of the estrogen receptor modulator tamoxifen, associated with luteinizing hormone-releasing hormone (lhrh); more recently, aromatase inhibitors (ais) have come into widespread use. The ais interfere with the last enzymatic step of estrogen synthesis in which androgens are converted into estrogens. Initially, the ais were used alone in postmenopausal patients to prevent disease recurrence, but together with lhrh analogs, they can be used in premenopausal patients to produce better estrogen suppression than can be achieved with tamoxifen plus a lhrh analog. Using a systematic review of the scientific literature (prospective and retrospective studies), we set out to assess the efficacy of ais compared with other endocrine therapy in various disease settings (neoadjuvant, adjuvant, metastatic).

The Role of Gonadotropin-Releasing-Hormone Analogues in the Treatment of Breast Cancer

The prognosis of premenopausal breast cancer patients with early disease has improved over the past decades, particularly in women expressing hormone receptors in their tumors. Tamoxifen, a selective estrogen receptor modulator, has dramatically changed outcomes in these patients and remains one of the standards of care. Ovarian function suppression by gonadotropin-releasing-hormone analogues (GnRHa) represents an additional treatment option. Long-term data are required before firm conclusions can be drawn, whereas recent clinical trials suggest that the use of GnRHa is effective in both adjuvant and metastatic settings, particularly in younger patients (<35 years old). The decision to select the optimal therapy should be individualized according to the biological characteristics of tumors, estimates of disease response, comorbidities, patient preference, and long-term toxicity.

Bilateral Salpingo-oophorectomy Compared to Gonadotropin-Releasing Hormone Agonists in Premenopausal Hormone Receptor-Positive Metastatic Breast Cancer Patients Treated with Aromatase Inhibitors

Purpose

Although combining aromatase inhibitors (AI) with gonadotropin-releasing hormone agonists (GnRHa) is becoming more common, it is still not clear if GnRHa is as effective as bilateral salpingo-oophorectomy (BSO).

Materials and Methods

We retrospectively analyzed data of 66 premenopausal patients with hormone receptor– positive, human epidermal growth factor receptor 2–negative recurrent and metastatic breast cancer who had been treated with AIs in combination with GnRHa or BSO between 2002 and 2015.

Results

The median patient age was 44 years. Overall, 24 (36%) received BSO and 42 (64%) received GnRHa. The clinical benefit rate was higher in the BSO group than in the GnRHa group (88% vs. 69%, p=0.092). Median progression-free survival (PFS) was longer in the BSO group, although statistical significance was not reached (17.2 months vs. 13.3 months, p=0.245). When propensity score matching was performed, the median PFS was 17.2 months for the BSO group and 8.2 months for the GnRHa group (p=0.137). Multivariate analyses revealed that the luminal B subtype (hazard ratio, 1.67; 95% confidence interval [CI], 1.08 to 2.60; p=0.022) and later-line treatment (≥ third line vs. first line; hazard ratio, 3.24; 95% CI, 1.59 to 6.59; p=0.001) were independent predictive factors for a shorter PFS. Incomplete ovarian suppression was observed in a subset of GnRHa-treated patients whose disease showed progression, with E2 levels higher than 21 pg/mL.

Conclusion

Both BSO and GnRHa were found to be effective in our AI-treated premenopausal metastatic breast cancer patient cohort. However, further studies in larger populations are needed to determine if BSO is superior to GnRHa.

Overview of elagolix for the treatment of endometriosis

INTRODUCTION

Suppression of sex-steroid secretion is required in a variety of gynecological conditions. This can be achieved using gonadotropin releasing hormone (GnRH) agonists that bind pituitary gonadotropin receptors and antagonize the link-receptor of endogenous GnRH, inhibiting the mechanism of GnRH pulsatility. On the other hand, GnRH antagonists immediately reduce gonadal steroid levels, avoiding the initial stimulatory phase of the agonists. Potential benefits of GnRH antagonists over GnRH agonists include a rapid onset and reversibility of action. Older GnRH antagonists are synthetic peptides, obtained by modifications of certain amino acids in the native GnRH sequence. They require subcutaneous injections, implantation of long-acting depots. The peptide structure is responsible for histamine-related adverse events and the tendency to elicit hypersensitivity reactions.

AREAS COVERED

Research has worked towards the development of non-peptidic molecules exerting antagonist action on GnRH. They are available for oral administration and may have a more beneficial safety profile in comparison with peptide GnRH antagonists. This article focuses on the data of the literature about elagolix, a novel non-peptidic GnRHantagonist, in the treatment of endometriosis.

EXPERT OPINION

Elagolix demonstrated efficacy in the management of endometriosis-associated pain and had an acceptable safety and tolerability profile. However, further studies are necessary to evaluate its non-inferiority in comparison with other endometriosis's treatments.

Advances in the Adjuvant and Neoadjuvant Treatment of Breast Cancer

Several advances in the adjuvant systemic therapy of primary breast cancer have occurred in the last decade and contributed to a decline in disease-related mortality. These include the introduction of aromatase inhibitors, new chemotherapy agents, and the novel antibody trastuzumab. New supportive treatments, such as growth factors, have contributed to the optimization of chemotherapy dose and schedule, and have improved the efficacy and safety of the treatment. In this review we will outline some of the recent advances in the adjuvant and neoadjuvant treatment of breast cancer. We will also discuss ongoing and proposed clinical trials.

Palliative systemic therapy for young women with metastatic breast cancer

PURPOSE OF REVIEW

Breast cancer in young women age less than 40 years remains a relatively rare disease. Emerging data suggest that the biology of breast cancer in younger women may differ from that of older women. Although metastatic breast cancer remains incurable, it is definitely treatable; especially in this era of emerging novel therapeutics.

RECENT FINDINGS

Most women have hormone receptor-positive disease and strategies that interfere with proliferation and the PI3 kinase pathway are reporting exciting results. The prognosis of the metastatic HER2 subtype has been extended to a median survival of 56 months with dual HER2 targeting agents in the first-line setting. Finally, triple negative breast cancer has an enlarging range of therapeutic options including immunotherapy, antiangiogenesis therapy, and targeted therapies including agents that interfere with androgen receptor signaling.

SUMMARY

Combined palliative and holistic approaches are essential to help young women navigate the marathon of treatment for metastatic breast cancer.

Twelve-Month Estrogen Levels in Premenopausal Women With Hormone Receptor-Positive Breast Cancer Receiving Adjuvant Triptorelin Plus Exemestane or Tamoxifen in the Suppression of Ovarian Function Trial (SOFT): The SOFT-EST Substudy

PURPOSE

To describe estradiol (E2), estrone (E1), and estrone sulfate (E1S) levels during the first year of monthly triptorelin plus exemestane or tamoxifen and to assess possible suboptimal suppression while receiving exemestane plus triptorelin.

PATIENTS AND METHODS

Premenopausal patients with early breast cancer on the Suppression of Ovarian Function Trial who selected triptorelin as the ovarian suppression method and were randomly assigned to exemestane plus triptorelin or tamoxifen plus triptorelin were enrolled until the target population of 120 patients was reached. Blood sampling time points were 0, 3, 6, 12, 18, 24, 36, and 48 months. Serum estrogens were measured with a highly sensitive and specific assay. This preplanned 12-month analysis evaluated E2, E1, E1S, follicle-stimulating hormone, and luteinizing hormone levels in all patients and the proportion of patients with E2 levels greater than 2.72 pg/mL at any time point during treatment with exemestane plus triptorelin.

RESULTS

One hundred sixteen patients (exemestane, n = 86; tamoxifen, n = 30; median age, 44 years; median E2, 51 pg/mL; 55% prior chemotherapy) started triptorelin and had one or more samples drawn. With exemestane plus triptorelin, median reductions from baseline E2, E1, and E1S levels were consistently ≥ 95%, resulting in significantly lower levels than with tamoxifen plus triptorelin at all time points. Among patients on exemestane plus triptorelin, 25%, 24%, and 17% had an E2 level greater than 2.72 pg/mL at 3, 6, and 12 months, respectively. Baseline factors related to on-treatment E2 level greater than 2.72 pg/mL were no prior chemotherapy (P = .06), higher body mass index (P = .05), and lower follicle-stimulating hormone and luteinizing hormone (each P < .01).

CONCLUSION

During the first year, most patients on exemestane plus triptorelin had E2 levels below the defined threshold of 2.72 pg/mL, consistent with levels reported in postmenopausal patients on aromatase inhibitors, but at each time point, at least 17% of patients had levels greater than the threshold.

New insights into endocrine therapy for young women with breast cancer

Managing estrogen receptor-positive breast cancer in young women (<40 years) requires a multidisciplinary/personalized approach, covering both clinical and psychosocial aspects. Five years of tamoxifen has been the standard adjuvant endocrine therapy for many years. Recent data from the adjuvant randomized trials TEXT-SOFT show that the aromatase inhibitor exemestane plus ovarian suppression significantly reduces recurrences as compared with tamoxifen plus ovarian suppression. The ATLAS and aTToM trials represent the first evidence of a beneficial effect of extended endocrine therapy with tamoxifen in premenopausal women. Outside of a clinical trial, no data support neoadjuvant endocrine therapy in young women. In the metastatic setting, tamoxifen or aromatase inhibitors, both with ovarian suppression/ablation, should be the preferred choice, unless rapid tumor shrinkage is needed. No data are available with fulvestrant in young patients.

Clinical utility of exemestane in the treatment of breast cancer

Breast cancer is the most prevalent cancer in women, causing a significant mortality worldwide. Different endocrine strategies are available for the treatment of hormone-sensitive breast cancer, including antiestrogen tamoxifen and fulvestrant, as well as third-generation aromatase inhibitors (AIs), such as letrozole, anastrozole, and exemestane. In this review, we will focus on exemestane, its clinical use, and its side effects. Exemestane is a steroidal third-generation AI now used in all treatment settings for breast cancer. In the metastatic disease, it has been extensively investigated as the first-, second-, and further-line treatment and it is now registered for the treatment of postmenopausal women with advanced estrogen-receptor-positive breast cancer whose disease has progressed following antiestrogen therapy. A potential lack of cross-resistance with nonsteroidal AIs has been described, giving additional therapeutic opportunities in sequences of endocrine agents. Exemestane is also approved for the adjuvant treatment of postmenopausal early breast cancer, either as upfront monotherapy for 5 years, as a switch following 2–3 years of tamoxifen, or as extended therapy beyond 5 years of adjuvant treatment. New promising data also showed a beneficial effect in young premenopausal early breast cancer patients, when administered together with ovarian suppression. Interesting results have also emerged when exemestane has been investigated as neodjuvant treatment as well as preventive agent in healthy women at high risk for breast cancer. Exemestane is generally well tolerated, with a side effect profile similar to that of other AIs, including menopausal symptoms, arthralgia, and bone loss. In conclusion, exemestane can be considered an effective and well-tolerated endocrine treatment option for all stages of breast cancer.

Adjuvant hormonal therapy and fertility preservation in premenopausal breast cancer: a survey among Italian oncologists

BACKGROUND

Increasing age of first pregnancy among Italian women with premenopausal breast cancer makes adjuvant hormonal therapy a hot topic, justifying a survey on the therapeutic approach of Italian oncologists.

MATERIALS & METHODS

From April to July 2012, an 11-item electronic questionnaire was submitted to Italian oncologists and 611 out of 974 invited filled questionnaires were collected from all over Italy.

RESULTS

In total, 97.7% of patients aged <40 years needing only hormonal therapy would receive both tamoxifen and luteinizing hormone-releasing hormone agonists (LHRHa); 2.3% tamoxifen or LHRHa alone. For the majority of oncologists LHRHa was also the preferred choice to preserving fertility.

CONCLUSION

Results are rather consistent with major guidelines but with a greater use of LHRHa and aromatase inhibitor.

Obesity and endocrine therapy: host factors and breast cancer outcome

Obesity is becoming increasingly prevalent and it has been linked to poor breast cancer outcomes. Because obesity is associated with increased adipose tissue mass and aromatase activity [the target of aromatase inhibitors (AIs)], there is concern that these agents may be less effective in women who are overweight or obese. Four of the randomized trials of AIs vs. tamoxifen conducted in the adjuvant breast cancer setting (ATAC, BIG 1-98 and TEAM in the postmenopausal setting and ABCSG-12 in the premenopausal setting) have reported effects of body mass index (BMI) on the relative effectiveness of an AI vs. tamoxifen. Obesity was confirmed as an adverse prognostic factor in ATAC and BIG 1-98 but not the TEAM study; in ABSCG-12, obesity was associated with poor outcomes in the anastrozole arm only. In the three postmenopausal trials, the use of an AI vs. tamoxifen was associated with better outcomes at all levels of BMI [all hazard ratios for recurrence <1, although 95% confidence intervals often included 1 due to lower power and smaller reductions in risk]. Of note, there was no significant interaction of BMI with letrozole (vs. tamoxifen) in the BIG 1-98 trial; while ATAC investigators concluded that the relative benefit of anastrozole (vs. tamoxifen) might be better in thinner (vs. heavier) women. In ABCSG-12, the use of anastrozole (vs. tamoxifen) was associated with significantly worse outcomes in women with BMI ≥25 kg/m(2) (similar to the detrimental effect of anastrozole on overall survival seen in the parent trial). These findings do not support the use of BMI as a predictor of AI (vs. tamoxifen) benefit in the adjuvant setting in postmenopausal breast cancer.

First international consensus guidelines for breast cancer in young women (BCY1)

The 1st International Consensus Conference for Breast Cancer in Young Women (BCY1) took place in November 2012, in Dublin, Ireland organized by the European School of Oncology (ESO). Consensus recommendations for management of breast cancer in young women were developed and areas of research priorities were identified. This manuscript summarizes these international consensus recommendations, which are also endorsed by the European Society of Breast Specialists (EUSOMA).

Breast cancer: current and future endocrine therapies

Endocrine therapy forms a central modality in the treatment of estrogen receptor positive breast cancer. The routine use of 5 years of adjuvant tamoxifen has improved survival rates for early breast cancer, and more recently has evolved in the postmenopausal setting to include aromatase inhibitors. The optimal duration of adjuvant endocrine therapy remains an active area of clinical study with recent data supporting 10 years rather than 5 years of adjuvant tamoxifen. However, endocrine therapy is limited by the development of resistance, this can occur by a number of possible mechanisms and numerous studies have been performed which combine endocrine therapy with agents that modulate these mechanisms with the aim of preventing or delaying the emergence of resistance. Recent trial data regarding the combination of the mammalian target of rapamycin (mTOR) inhibitor, everolimus with endocrine therapy have resulted in a redefinition of the clinical treatment pathway in the metastatic setting. This review details the current endocrine therapy utilized in both early and advanced disease, as well as exploring potential new targets which modulate pathways of resistance, as well as agents which aim to modulate adrenal derived steroidogenic hormones.

Insights on adjuvant endocrine therapy for premenopausal and postmenopausal breast cancer

In 2005, cancer accounted for 13% of all deaths worldwide. Breast cancer is the number-one cause of cancer-related death among women in the USA, affecting 178,480 of them in 2007. As 75% of tumors in postmenopausal women and half in premenopausal women express estrogen receptor, endocrine therapy plays a significant role as a systemic treatment. Robust datasets have demonstrated the impact of tamoxifen in reducing breast cancer recurrence and mortality, regardless of the age of the patient. Other estrogen-deprivation strategies, such as aromatase inhibitors in postmenopausal women and luteinizing hormone-releasing hormone agonists in premenopausal women, are being increasingly used for estrogen receptor-positive breast cancer. This review discusses basic principles regarding endocrine therapy, the need for accurate estrogen receptor testing and the role of menopause in therapy selection.

Use of goserelin in the treatment of breast cancer

Gonadotropin-releasing hormone analogs are, alongside tamoxifen, one of the most commonly used drugs in the treatment of pre-/perimenopausal endocrine-responsive breast cancer. Goserelin, as a principal agent of this class of drugs, is mainly investigated in clinical trials. The indirect comparison of goserelin with tamoxifen as a single drug in the adjuvant setting showed similar efficacy. Furthermore, goserelin is as effective as cyclophosphamide, methotrexate and 5-fluorouracil chemotherapy, and total endocrine blockade as a combination of gonadotropin-releasing hormone analog and tamoxifen showed a comparable benefit with anthracycline-containing adjuvant chemotherapy. Goserelin administered after cessation of chemotherapy leads to a further improvement and may be equieffective as tamoxifen or a combination of both. Data concerning taxane-based and dose-dense chemotherapy as well as combination of gonadotropin-releasing hormone analogs with third-generation aromatase inhibitors are still lacking (ongoing suppression of ovarian function, tamoxifen and exemestane, and premenopausal endocrine-responsive chemotherapy trials). Moreover, duration of therapy with gonadotropin-releasing hormone analogs (2-3 years or longer) is still a matter of debate. Palliative endocrine treatment is standard in the first-line therapy of patients without life-threatening disease and endocrine-responsive breast cancer. Treatment decisions depend upon adjuvant endocrine pretreatment. Clinical data regarding ovarian protection by synchronous use of gonadotropin-releasing hormone in young breast cancer patients receiving chemotherapy are incoherent.

Endocrine therapy and other targeted therapies for metastatic breast cancer

The most important change in the treatment of advanced breast cancer that will emerge over the next 10 years is the shift from adjuvant tamoxifen to adjuvant aromatase inhibitors. This will mean an increasing proportion of tamoxifen-naive aromatase inhibitor-resistant breast cancer. Research of the most appropriate methods of optimizing remaining endocrine sensitivity in these patients is needed. The rapid expansion in the understanding of the molecular basis of breast cancer biology provides potential targets for novel therapies. Despite these pivotal developments, resistance to endocrine therapy remains a key limitation in the management of advanced breast cancer. Until recently, the only option following the development of resistance to an endocrine agent was to change endocrine therapy and, on exhaustion of endocrine sensitivity, to move to cytotoxic chemotherapy. Understanding of at least some of the mechanisms underlying the development of endocrine resistance is now emerging. We now have the tools that may allow us to both overcome resistance and restore sensitivity, or to pre-empt certain types of resistance from developing. These tools include the increasing array of signal transduction inhibitors in combination with standard endocrine agents. Correct clinical management strategy can be guided by preclinical modeling but can only be validated by carefully designed clinical trials. These will, at the very least, need to be conducted with correlative translational research elements that will track changes in tumors as resistance emerges and will allow us to select the most appropriate treatment strategy for individual patients. Amongst the myriad of promising drugs there will undoubtedly be some that fail to meet current hopes, but we can be optimistic that a handful will find a useful place in keeping advanced breast cancer at bay for longer than can be achieved at present. However, the holy grail of a cure is likely, in the medium term, to remain elusively at the end of the rainbow for most of these patients. Several other methods for the management of these patients are in development. These include strategies to overcome endocrine resistance and methods to target deregulated endocrine and growth factor signaling pathways using gene and immunotherapy approaches.

Luteinizing hormone-releasing hormone agonist plus an aromatase inhibitor as second-line endocrine therapy in premenopausal females with hormone receptor-positive metastatic breast cancer

PURPOSE

The aim of the current study was to explore the efficacy and safety of combination therapy using a luteinizing hormone-releasing hormone (LHRH) agonist plus an aromatase inhibitor (AI) as second-line therapy in premenopausal females with hormone receptor (HR)-positive recurrent or metastatic breast cancer (MBC).

METHODS

A retrospective analysis was conducted in patients registered in the breast cancer database of our institution between January 2001 and December 2012. The breast cancer database identified 14 premenopausal patients who had been treated with an LHRH agonist plus AI for HR-positive recurrent or MBC.

RESULTS

Fourteen patients with recurrent breast cancer (N = 10) or metastatic disease at primary diagnosis (N = 4) were included in the present study. All patients had previously been treated with an LHRH agonist plus tamoxifen. The clinical benefit rate was 71.4% and the median TTP was 11 months (95% confidence interval 1.7-20.3 months). One patient discontinued treatment because of liver dysfunction (grade 3).

CONCLUSIONS

The combination of an LHRH agonist plus an AI is a treatment option for premenopausal females with HR-positive MBC that can prolong the chemotherapy-free interval and yield effective disease stabilization.

Hormonal therapies in young breast cancer patients: when, what and for how long?

Breast cancer in young women (<40 years) is a rare and complex clinical and psychosocial condition, which deserves multidisciplinary and personalized approaches. In young women with hormone-receptor positive disease, 5 years of adjuvant tamoxifen, with or without ovarian suppression/ablation, is considered the standard endocrine therapy. The definitive role of adjuvant aromatase inhibitors has still to be elucidated: the upcoming results of the Tamoxifen and EXemestane Trial (TEXT) and Suppression of Ovarian Function Trial (SOFT) trials will help understanding if we can widen our current endocrine therapeutic options. The optimal duration of adjuvant endocrine therapy in young women also remains an unresolved issue. The recently reported results of the ATLAS and aTToM trials represent the first evidence of a beneficial effect of extended endocrine therapy in premenopausal women and provide an important opportunity in high-risk young patients. In the metastatic setting, endocrine therapy should be the preferred choice for endocrine responsive disease, unless there is evidence of endocrine resistance or need for rapid disease and/or symptom control. Tamoxifen in combination with ovarian suppression/ablation remains the 1st-line endocrine therapy of choice. Aromatase inhibitors in combination with ovarian suppression/ablation can be considered after progression on tamoxifen and ovarian suppression/ablation. Fulvestrant has not yet been studied in pre-menopausal women. Specific age-related treatment side effects (i.e., menopausal symptoms, change in body image and weight gain, cognitive function impairment, fertility damage/preservation, long-term organ dysfunction, sexuality) and the social impact of diagnosis and treatment (i.e., job discrimination, family management) should be carefully addressed when planning long-lasting endocrine therapies in young women with hormone-receptor positive early and advanced breast cancer.

Role of goserelin in combination with endocrine therapy for the treatment of advanced breast cancer in premenopausal women positive for hormone receptor: a retrospective matched case-control study

OBJECTIVE

This research was to investigate the role of goserelin in combination with endocrine therapy for the treatment of advanced breast cancer in premenopausal women positive for hormone receptors.

METHODS

We retrospectively analyzed 40 patients as the treatment group with advanced breast cancer who, were positive for hormone receptors, received goserelin in combination with endocrine therapy and 40 patients as the control group received endocrine therapy alone, matched for age, gender, receptor status, and tumor stage.

RESULTS

The median period of follow-up was 38.9 months. The response status at 6 months, the overall clinical benefit rate was 87.5% and 70.0% in the treatment group and control group, respectively. The mean progression-free survival (PFS) in the treatment group and control group was 27.9 and 16.9 months, respectively. The 1-, 2-, and 3-year PFS rates were 87.5%, 66.2%, and 49.7%, respectively, in the treatment group and 59.2%, 38.8%, and 35.3%, respectively, in the control group (p=0.076). The 1-, 2-, and 3-year overall survival (OS) rates were 100%, 87.2%, and 76.6%, respectively, in the treatment group and 90.0%, 74.2%, and 55.8%, respectively, in the control group (p=0.048). For the treatment group with age <40 years, PFS (p=0.036) and OS (p=0.014) were significantly longer than the control group, but it was no effect on the prognosis with the patients aged ≥40 years. Continued use of goserelin after disease progress again in the median survival time was significantly longer than nonusers (28.2 months vs. 7.0 months), and there is the potential benefit of OS (p=0.070).

CONCLUSIONS

For premenopausal hormone receptor-positive advanced breast cancer, goserelin-combined endocrine therapy can be used for those <40 years, the standard endocrine treatment for patients, we recommend continued use of goserelin for patients with disease progress again.

Endocrine therapy for advanced/metastatic breast cancer

First-line endocrine therapy by estrogen antagonism or suppression of estrogen achieves objective responses (ORs) and clinical benefit (CB) in around 30% and 50% of estrogen receptor-positive metastatic breast cancer patients, respectively. Aromatase inhibitors (AIs) are the most effective treatment in previously untreated postmenopausal women. Tamoxifen is an effective alternative. The optimal endocrine therapy on relapse remains uncertain. Tamoxifen and fulvestrant achieve CB in around 50% of patients and ORs of 10%. CB of exemestane after nonsteroidal AIs is 30% to 50% but ORs are rare. Targeted agents (eg, everolimus) plus endocrine therapy are likely to become increasingly important in overcoming endocrine resistance.

The aromatase inhibitors (plus ovarian function suppression) in premenopausal breast cancer patients: ready for prime time?

Tamoxifen alone or the combination of ovarian function suppression (OFS) and tamoxifen are the mainstay of hormonal therapy in premenopausal women with endocrine-responsive breast cancer. The results of large trials conducted with the third generation of aromatase inhibitors (AIs) in the metastatic, neoadjuvant and adjuvant setting, indicated better outcomes among postmenopausal breast cancer patients with endocrine responsive disease given AIs than among those given tamoxifen. These results supported the investigation of AIs in combination with OFS in premenopausal women with hormone receptor positive breast cancer. In this article we reviewed the efficacy and toxicity data on the use of AIs combined with OFS in premenopausal breast cancer patients in metastatic, neoadjuvant and adjuvant setting. Given the available evidence at the time in metastatic setting for premenopausal patients suitable of endocrine therapy the AI is a viable option, if tamoxifen resistance is proven, although mandates the use of OFS. In neoadjuvant setting the AIs in combination of OFS should not be used outside of a clinical trial. In the adjuvant setting, tamoxifen alone or OFS plus tamoxifen are reasonable options. Despite the lack of conclusive data favoring the combination of tamoxifen plus OFS, this treatment might be a reasonable option for subgroups of patients such as very young patients, OFS alone should nort be considered unless tamoxifen was contraindicated. Similarly, in cases where tamoxifen is contraindicated, AIs as an adjunct to OFS is a treatment option in premenopausal patients. New large randomized studies are required to confirm the role of OFS plus an AI in premenopausal women.

Efficacy of goserelin plus anastrozole in premenopausal women with advanced or recurrent breast cancer refractory to an LH-RH analogue with tamoxifen: results of the JMTO BC08-01 phase II trial

The aim of the present study was to assess the efficacy and tolerability of a luteinizing hormone-releasing hormone (LH-RH) analogue plus an aromatase inhibitor following failure to respond to standard LH-RH analogue plus tamoxifen (TAM) in premenopausal patients. Premenopausal women with estrogen receptor (ER)-positive and/or progesterone-receptor positive, advanced or recurrent breast cancer refractory to an LH-RH analogue plus TAM received goserelin (GOS) in conjunction with anastrozole (ANA). The primary endpoint was the objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), clinical benefit rate (CBR) and safety. Between September 2008 and November 2010, 37 patients were enrolled. Thirty-five patients (94.6%) had ER-positive tumors, and 36 (97.3%) had human epidermal growth factor receptor (HER) 2-negative tumors. Thirty-six (97.3%) had measurable lesions and 1 (2.7%) had only bone metastasis. The ORR was 18.9% [95% confidence interval (CI), 8.0–35.2%], the CBR was 62.2% (95% CI, 44.8–77.5%) and the median PFS was 7.3 months. Eight patients had adverse drug reactions but none resulted in discontinuation of treatment. GOS plus ANA is a safe effective treatment for premenopausal women with hormone receptor-positive, recurrent or advanced breast cancer. The treatment may become viable treatment in the future, particularly when TAM is ineffective or contraindicated. Further studies and discussion are warranted.

The European Society of Breast Cancer Specialists recommendations for the management of young women with breast cancer

EUSOMA (The European Society of Breast Cancer Specialists) is committed to writing recommendations on different topics of breast cancer care which can be easily adopted and used by health professionals dedicated to the care of patients with breast cancer in their daily practice. In 2011, EUSOMA identified the management of young women with breast cancer as one of the hot topics for which a consensus among European experts was needed. Therefore, the society recently organised a workshop to define such recommendations. Thirteen experts from the different disciplines met for two days to discuss the topic. This international and multidisciplinary panel thoroughly reviewed the literature in order to prepare evidence-based recommendations. During the meeting, two working groups were set up to discuss in detail diagnosis and loco-regional and systemic treatments, including both group aspects of psychology and sexuality. The conclusions reached by the working groups were then discussed in a plenary session to reach panel consensus. Whenever possible, a measure of the level of evidence (LoE) from 1 (the highest) to 4 (the lowest) degree, based on the methodology proposed by the US Agency for Healthcare Research and Quality (AHRQ), was assigned to each recommendation. The present manuscript presents the recommendations of this consensus group for the management of young women with breast cancer in daily clinical practice.

Breast cancer in young women: climbing for progress in care and knowledge

Approximately a third of newly diagnosed invasive breast cancers occur in women aged under 50 years and it is likely that the incidence of the disease in younger women will further increase as a result of demographic and lifestyle changes and progress in screening. Breast cancer in young women is different from that in older patients. Young women with breast cancer represent a distinct population for which tailored diagnostic, therapeutic and supportive interventions are required. This review highlights the complex diagnostic and therapeutic processes that women and care providers are faced with. Topics addressed include the need for more sensitive and specific diagnostic tools that are capable of detecting cancer in dense breasts, the development of individualized surgical and medical treatments in the early and advanced disease setting aimed at improving outcome and reducing long-term side effects, and adequate psychosocial interventions.

GnRH receptors in cancer: from cell biology to novel targeted therapeutic strategies

The crucial role of pituitary GnRH receptors (GnRH-R) in the control of reproductive functions is well established. These receptors are the target of GnRH agonists (through receptor desensitization) and antagonists (through receptor blockade) for the treatment of steroid-dependent pathologies, including hormone-dependent tumors. It has also become increasingly clear that GnRH-R are expressed in cancer tissues, either related (i.e. prostate, breast, endometrial, and ovarian cancers) or unrelated (i.e. melanoma, glioblastoma, lung, and pancreatic cancers) to the reproductive system. In hormone-related tumors, GnRH-R appear to be expressed even when the tumor has escaped steroid dependence (such as castration-resistant prostate cancer). These receptors are coupled to a G(αi)-mediated intracellular signaling pathway. Activation of tumor GnRH-R by means of GnRH agonists elicits a strong antiproliferative, antimetastatic, and antiangiogenic (more recently demonstrated) activity. Interestingly, GnRH antagonists have also been shown to elicit a direct antitumor effect; thus, these compounds behave as antagonists of GnRH-R at the pituitary level and as agonists of the same receptors expressed in tumors. According to the ligand-induced selective-signaling theory, GnRH-R might assume various conformations, endowed with different activities for GnRH analogs and with different intracellular signaling pathways, according to the cell context. Based on these consistent experimental observations, tumor GnRH-R are now considered a very interesting candidate for novel molecular, GnRH analog-based, targeted strategies for the treatment of tumors expressing these receptors. These agents include GnRH agonists and antagonists, GnRH analog-based cytotoxic (i.e. doxorubicin) or nutraceutic (i.e. curcumin) hybrids, and GnRH-R-targeted nanoparticles delivering anticancer compounds.

Analysis of Ki-67 expression with neoadjuvant anastrozole or tamoxifen in patients receiving goserelin for premenopausal breast cancer

BACKGROUND

The increasing costs associated with large-scale adjuvant trials mean that the prognostic value of biologic markers is increasingly important. The expression of nuclear antigen Ki-67, a marker of cell proliferation, has been correlated with treatment efficacy and is being investigated for its value as a predictive marker of therapeutic response. In the current study, the authors explored correlations between Ki-67 expression and tumor response, estrogen receptor (ER) status, progesterone receptor (PgR) status, and histopathologic response from the STAGE study (S_tudy of T_amoxifen or A_rimidex, combined with G_oserelin acetate to compare E_fficacy and safety).

METHODS

In a phase 3, double-blind, randomized trial (National Clinical Trials identifier NCT00605267), premenopausal women with ER-positive, early stage breast cancer received either anastrozole plus goserelin or tamoxifen plus goserelin for 24 weeks before surgery. The Ki-67 index, hormone receptor (ER and PgR) status, and histopathologic responses were determined from histopathologic samples that were obtained from core-needle biopsies at baseline and at surgery. Tumor response was determined by using magnetic resonance imaging or computed tomography.

RESULTS

In total, 197 patients were randomized to receive either anastrozole plus goserelin (n = 98) or tamoxifen plus goserelin (n = 99). The best overall tumor response was better for the anastrozole group compared with the tamoxifen group both among patients who had a baseline Ki-67 index ≥20% and among those who had a baseline Ki-67 index <20%. There was no apparent correlation between baseline ER status and the Ki-67 index in either group. Positive PgR status was reduced from baseline to week 24 in the anastrozole group.

CONCLUSIONS

In premenopausal women with ER-positive breast cancer, anastrozole produced a greater best overall tumor response compared with tamoxifen regardless of the baseline Ki-67 index.

The sequential use of endocrine treatment for advanced breast cancer: where are we?

BACKGROUND

Hormone receptor-positive advanced breast cancer is an increasing health burden. Although endocrine therapies are recognised as the most beneficial treatments for patients with hormone receptor-positive advanced breast cancer, the optimal sequence of these agents is currently undetermined.

METHODS

We reviewed the available data on randomised controlled trials (RCTs) of endocrine therapies in this treatment setting with particular focus on RCTs reported over the last 15 years that were designed based on power calculations on primary end points.

RESULTS

In this paper, data are reviewed in postmenopausal patients for the use of tamoxifen, aromatase inhibitors and fulvestrant. We also consider the available data on endocrine crossover studies and endocrine therapy in combination with chemotherapy or growth factor therapies. Treatment options for premenopausal patients and those with estrogen receptor-/human epidermal growth factor receptor 2-positive tumours are also evaluated.

CONCLUSION

We present the level of evidence available for each endocrine agent based on its efficacy in advanced breast cancer and a diagram of possible treatment pathways.

Ovarian function suppression and fulvestrant as endocrine therapy in premenopausal women with metastatic breast cancer

BACKGROUND

Endocrine therapy is the preferred treatment for hormone-receptor (HR) positive metastatic breast cancer. In premenopausal patients, ovarian function suppression with goserelin in combination with anastrozole yielded promising results in phase II studies. Fulvestrant, a pure antioestrogen, yields high rates of disease stabilisation in postmenopausal women. Therefore, we investigated the feasibility and safety of fulvestrant plus goserelin in premenopausal women with HR-positive metastatic breast cancer.

METHODS

Premenopausal patients with metastatic breast cancer eligible for endocrine treatment received fulvestrant 250 mg and goserelin 3.6 mg every four weeks as first- to fourth-line therapy. Clinical benefit rate (CBR; response rate plus disease stabilisation ≥ 6 months) was defined as the primary study end-point. Time to progression (TTP) and overall survival (OS) were estimated using the Kaplan-Meier product limit method.

FINDINGS

Twenty-six patients received treatment as scheduled. 81% were pre-treated with tamoxifen and 69% had received prior aromatase inhibitors in combination with goserelin. The majority of patients (69%) presented with visceral metastases. Complete response was observed in a single patient, partial response in three and disease stabilisation ≥ 6 months in eleven patients, resulting in a CBR of 58%. Median TTP was 6 months (95%confidence interval (CI), 2.4-9.6) and OS 32 months (95%CI, 14.28-49.72), respectively.

INTERPRETATION

Results suggest that the combination of fulvestrant and goserelin offers promising activity in premenopausal patients and further investigation is warranted.

Neoadjuvant anastrozole versus tamoxifen in patients receiving goserelin for premenopausal breast cancer (STAGE): a double-blind, randomised phase 3 trial

BACKGROUND

Aromatase inhibitors have shown increased efficacy compared with tamoxifen in postmenopausal early breast cancer. We aimed to assess the efficacy and safety of anastrozole versus tamoxifen in premenopausal women receiving goserelin for early breast cancer in the neoadjuvant setting.

METHODS

In this phase 3, randomised, double-blind, parallel-group, multicentre study, we enrolled premenopausal women with oestrogen receptor (ER)-positive, HER2-negative, operable breast cancer with WHO performance status of 2 or lower. Patients were randomly assigned (1:1) to receive goserelin 3·6 mg/month plus either anastrozole 1 mg per day and tamoxifen placebo or tamoxifen 20 mg per day and anastrozole placebo for 24 weeks before surgery. Patients were randomised sequentially, stratified by centre, with randomisation codes. All study personnel were masked to study treatment. The primary endpoint was best overall tumour response (complete response or partial response), assessed by callipers, during the 24-week neoadjuvant treatment period for the intention-to-treat population. The primary endpoint was analysed for non-inferiority (with non-inferiority defined as the lower limit of the 95% CI for the difference in overall response rates between groups being 10% or less); in the event of non-inferiority, we assessed the superiority of the anastrozole group versus the tamoxifen group. We included all patients who received study medication at least once in the safety analysis set. We report the primary analysis; treatment will also continue in the adjuvant setting for 5 years. This trial is registered with ClinicalTrials.gov, number NCT00605267.

FINDINGS

Between Oct 2, 2007, and May 29, 2009, 204 patients were enrolled. 197 patients were randomly assigned to anastrozole (n=98) or tamoxifen (n=99), and 185 patients completed the 24-week neoadjuvant treatment period and had breast surgery (95 in the anastrazole group, 90 in the tamoxifen group). More patients in the anastrozole group had a complete or partial response than did those in the tamoxifen group during 24 weeks of neoadjuvant treatment (anastrozole 70·4% [69 of 98 patients] vs tamoxifen 50·5% [50 of 99 patients]; estimated difference between groups 19·9%, 95% CI 6·5-33·3; p=0·004). Two patients in the anastrozole group had treatment-related grade 3 adverse events (arthralgia and syncope) and so did one patient in the tamoxifen group (depression). One serious adverse event was reported in the anastrozole group (benign neoplasm, not related to treatment), compared with none in the tamoxifen group.

INTERPRETATION

Given its favourable risk-benefit profile, the combination of anastrozole plus goserelin could represent an alternative neoadjuvant treatment option for premenopausal women with early-stage breast cancer.

FUNDING

AstraZeneca.

Current role and safety profile of aromatase inhibitors in early breast cancer

The current adjuvant therapy for breast cancer is in a continous progress; standard therapeutic strategies include the use of chemotherapy, molecular targeted drugs and hormonal agents, according to well-established prognostic and predictive factors. Among the hormonal drugs, for a long period tamoxifen has been the gold standard of adjuvant therapy in postmenopausal women with hormone receptor-positive (HR+) early breast cancer. In the last years an expanding use of aromatase inhibitors occurred in this subset of patients, because the third-generation class of these agents (anastrozole, letrozole and exemestane) showed to be more effective and safe than tamoxifen and are now recommended as the preferred hormonal approach to postmenopausal hormone-sensitive patients, according to national and international guidelines. Treatment choices with these agents include the use of an aromatase inhibitor as an upfront strategy for 5 years, as a sequential approach after 2-3 years of tamoxifen, or as an extended use after the classical 5 years of tamoxifen. The improved efficacy of aromatase inhibitors over tamoxifen has been largely demonstrated in terms of better disease-free survival, reductions in the occurrence of early distant metastasis as well as improvement of overall survival. Moreover, according to the optimal duration of therapy, presently it is not known whether aromatase inhibitor therapy, as tamoxifen, should be limited to 5 years. In terms of safety profile, the side effects of aromatase inhibitors, as compared with selective estrogen receptor modulators, are different, reflecting the specific mechanism of action of these drugs. There is strong evidence that aromatase inhibitors are well tolerated, with a lower incidence of gynecological symptoms (vaginal bleeding, discharge and endometrial neoplasia), venous thromboembolic events and hot flushes than tamoxifen. On the other hand, the use of aromatase inhibitors has been associated with loss of bone density, arthralgia, myalgia, and a negative effect on lipid metabolism and cardiovascular risk. More extensive and mature studies are necessary to well establish the safety of aromatase inhibitors when given to patients with breast cancer for a long time.

Adjuvant endocrine therapy plus zoledronic acid in premenopausal women with early-stage breast cancer: 62-month follow-up from the ABCSG-12 randomised trial

BACKGROUND

Analysis of the Austrian Breast and Colorectal Cancer Study Group trial-12 (ABCSG-12) at 48 months' follow-up showed that addition of zoledronic acid to adjuvant endocrine therapy significantly improved disease-free survival. We have now assessed long-term clinical efficacy including disease-free survival and disease outcomes in patients receiving anastrozole or tamoxifen with or without zoledronic acid.

METHODS

ABSCG-12 is a randomised, controlled, open-label, two-by-two factorial, multicentre trial in 1803 premenopausal women with endocrine-receptor-positive early-stage (stage I-II) breast cancer receiving goserelin (3.6 mg every 28 days), comparing the efficacy and safety of anastrozole (1 mg per day) or tamoxifen (20 mg per day) with or without zoledronic acid (4 mg every 6 months) for 3 years. Randomisation (1:1:1:1 ratio) was computerised and based on the Pocock and Simon minimisation method to balance the four treatment arms across eight prognostic variables (age, neoadjuvant chemotherapy, pathological tumour stage; lymph-node involvement, type of surgery or locoregional therapy, complete axillary dissection, intraoperative radiation therapy, and geographical region). Treatment allocation was not masked. The primary endpoint was disease-free survival (defined as disease recurrence or death) and analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00295646; follow-up is ongoing.

FINDINGS

At a median follow-up of 62 months (range 0-114.4 months), more than 2 years after treatment completion, 186 disease-free survival events had been reported (53 events in 450 patients on tamoxifen alone, 57 in 453 patients on anastrozole alone, 36 in 450 patients on tamoxifen plus zoledronic acid, and 40 in 450 patients on anastrozole plus zoledronic acid). Zoledronic acid reduced risk of disease-free survival events overall (HR 0.68, 95% CI 0.51-0.91; p=0.009), although the difference was not significant in the tamoxifen (HR 0.67, 95% CI 0.44-1.03; p=0.067) and anastrozole arms (HR 0.68, 95% CI 0.45-1.02; p=0.061) assessed separately. Zoledronic acid did not significantly affect risk of death (30 deaths with zoledronic acid vs 43 deaths without; HR 0.67, 95% CI 0.41-1.07; p=0.09). There was no difference in disease-free survival between patients on tamoxifen alone versus anastrozole alone (HR 1.08, 95% CI 0.81-1.44; p=0.591), but overall survival was worse with anastrozole than with tamoxifen (46 vs 27 deaths; HR 1.75, 95% CI 1.08-2.83; p=0.02). Treatments were generally well tolerated, with no reports of renal failure or osteonecrosis of the jaw. Bone pain was reported in 601 patients (33%; 349 patients on zoledronic acid vs 252 not on the drug), fatigue in 361 (20%; 192 vs 169), headache in 280 (16%; 147 vs 133), and arthralgia in 266 (15%; 145 vs 121).

INTERPRETATION

Addition of zoledronic acid improved disease-free survival in the patients taking anastrozole or tamoxifen. There was no difference in disease-free survival between patients receiving anastrozole and tamoxifen overall, but those on anastrozole alone had inferior overall survival. These data show persistent benefits with zoledronic acid and support its addition to adjuvant endocrine therapy in premenopausal patients with early-stage breast cancer.

FUNDING

AstraZeneca; Novartis.

Letrozole plus GnRH analogue as preoperative and adjuvant therapy in premenopausal women with ER positive locally advanced breast cancer

Patients with large ER positive tumors candidate to preoperative chemotherapy may also benefit from a concurrent endocrine intervention, but this issue has been scarcely investigated due to concerns arising from unfavorable results emerged from an adjuvant trial of concurrent tamoxifen and chemotherapy. We retrospectively investigated the activity of letrozole plus GnRH analogue (GnRH-a) administered concurrently with preoperative chemotherapy and as adjuvant treatment in premenopausal women with locally advanced ER positive breast cancer consecutively admitted at the European Institute of Oncology. Results were compared with those of a non-randomized unmatched control group of premenopausal women with locally advanced ER positive breast cancer receiving preoperative chemotherapy, followed by tamoxifen and GnRH-a after surgery. Primary endpoints were pathological complete response (pCR) rate, decrease of Ki67 and disease free survival (DFS). One-hundred and nineteen women constituted the study group, while 95 patients served as controls. The pCR rate was 5.0 vs 1.1% in the study and control group, respectively. A statistically significant greater suppression of Ki67 was observed in patients receiving chemoendocrine therapy as compared with controls (P = 0.003). At a median follow up of 59 months, 26 events occurred in the chemoendocrine group and 48 in the control group. Five-year DFS was 78 vs 41% in the study and in the control group, respectively [adjusted HR 0.46, 95% CI 0.27-0.79, P = 0.0047]. The concurrent administration of letrozole and GnRH-a with preoperative chemotherapy was highly effective in premenopausal women with large ER positive breast cancer in terms of decreased proliferation and of improved DFS. Randomized studies are warranted to establish the role of the addition of endocrine therapy to chemotherapy as standard preoperative approach for ER positive locally advanced breast cancer as well as of letrozole in combination with GnRH-a for the treatment of premenopauasal women with early breast cancer.

Goserelin plus letrozole as first- or second-line hormonal treatment in premenopausal patients with advanced breast cancer

A promising new option as the treatment of choice for premenopausal patients with metastatic breast cancer (MBC) could be the combination of a luteinising hormone-releasing hormone analog and an aromatase inhibitor. Very little data about the use of goserelin with anastrozole in advanced breast cancer are available, and no cohort studies on the efficacy of goserelin with letrozole in advanced premenopausal breast cancer patients have been reported. We present the single-centre, retrospective, experience of goserelin plus letrozole in a total of 52 premenopausal women with MBC. All patients received goserelin 3.6 mg by subcutaneous injection every 4 weeks along with letrozole 2.5 mg daily as first-line (n=36) and second-line (n=16) hormonal treatment. The median duration of goserelin with letrozole treatment was 11 (range, 2-61) months, and the median duration of overall follow-up was 31 (range, 3-66) months. The objective response rate (ORR) was 21.1%, with two complete response (CR) (3.8%) and nine partial response (PR) (17.3%). Stable disease (SD) lasting more than 6 months was achieved by 26 patients (50.0%). Thus, goserelin with letrozole conferred clinical benefit (CB) in 37 women (71.1%). The progression-free survival (PFS) was 10 months. CR was exclusively observed in hormone receptor-double-positive patients. Drug therapy was well tolerated; no grade 3/4 toxicities were reported. Goserelin plus letrozole appears to be an efficacious and well-tolerated regimen in women with advanced breast cancer. Further prospectively randomized studies involving more patients and longer follow-up are indicated.