Endocrinology and hormone therapy in breast cancer: endocrine therapy in premenopausal women

Significance of Ovarian Function Suppression in Endocrine Therapy for Breast Cancer in Pre-Menopausal Women

Ovarian function suppression (OFS) for treating breast cancer in pre-menopausal women was introduced for the first time in the late 19th century as bilateral oophorectomy. It was not until the 1960s that the oestrogen receptor was identified and a test for detecting endocrine sensitivity of the breast cancer was developed. A weakness of early trials on OFS for breast cancer treatment is therefore their failure to take receptor sensitivity into account when selecting participants. A meta-analysis performed in the early 1990s first proved that adjuvant OFS significantly improved the cure rate of oestrogen receptor-positive breast cancer in pre-menopausal women regardless of whether it was carried out through oophorectomy, radiation-induced ablation or drug therapy. In the 1970s, tamoxifen was synthesized. It became one of the most important cancer drugs and today constitutes the gold standard for endocrine adjuvant therapy. Taking tamoxifen for a five-year period lowers mortality by 30 % over 15 years. Ten years of tamoxifen therapy reduces mortality even further, with increased side effects, however. Research over the past ten years has proven that for post-menopausal women, aromatase inhibitors have benefits over tamoxifen. Current trial results have rekindled the debate about the combination of OFS with tamoxifen or with aromatase inhibitors for adjuvant breast cancer treatment of pre-menopausal women. These trials have reported an improvement in disease-free survival in patients with a high risk of recurrence when they are treated with a combination of OFS plus tamoxifen or aromatase inhibitors, especially in women younger than 35. However, combination therapy causes significantly more side effects, which could negatively impact compliance. Endocrine treatments administered over a period of many years show waning compliance, which tends to be only around 50 % after five years. Inadequate compliance compromises efficacy and increases the risk of mortality. For this reason, when indicating and supporting endocrine adjuvant therapy, physicians must ensure that compliance will be good. To prevent recurrence in the long run, it is much more effective to prescribe a somewhat less effective therapy that will actually be carried out than to prescribe one that is theoretically more effective, but is not adhered to consistently.

Influence of sex steroids on inflammation and bone metabolism

Sex steroids are central to sexual development and reproduction, exerting pleiotropic effects on multiple tissues and organs throughout the lifespan of humans. Sex steroids are fundamental to skeletal development, bone homeostasis and immune function. The composite effect of sex-specific genetic architecture and circulating levels of sex-steroid hormones closely parallels differences in the immune response and may account for corresponding sex-related differences in risk for chronic periodontitis, with men exhibiting greater susceptibility than women. Age-associated reductions in sex steroids also provide insight into apparent temporal increases in susceptibility to periodontitis and alveolar bone loss, particularly among women. Chronic infection and inflammatory conditions, such as periodontal disease, provide a unique platform for exploring the interface of sex steroids, immunity and bone metabolism.

High-intensity focused ultrasound compared with irradiation for ovarian castration in premenopausal females with hormone receptor-positive breast cancer after radical mastectomy

The aim of the current study was to determine the feasibility, efficacy and safety of ovarian castration by high-intensity focused ultrasound (HIFU) in premenopausal patients with estrogen receptor (ER)(+)/progesterone receptor (PR)(+) breast cancer subsequent to radical mastectomy. A total of 88 premenopausal females with pathologically confirmed ER(+)/PR(+) breast cancer following radical mastectomy were randomly and equally divided into two groups that received HIFU therapy or radiation treatment. HIFU therapy was applied twice at an interval of three days and radiotherapy was administered to a total prescribed dose of D(T) 18 Gy in nine fractions over 11 days. Outcome measures included serum levels of estradiol and estrone, the Kupperman index and the incidence of secondary amenorrhea. Adverse events were monitored and recorded. All patients were followed up for 12 months. Serum levels of estradiol and estrone were comparable prior to treatment between the HIFU and radiation treatment groups. One month following treatment, serum levels of estradiol and estrone were significantly decreased in the two groups, but a greater decline was observed in the HIFU treatment group (P<0.01 and 0.05, respectively). In addition, more patients developed severe menopausal symptoms and amenorrhea in the HIFU therapy group compared with the radiotherapy group (P<0.01 for the two groups). A total of 3 months following treatment, serum levels of estradiol and estrone and the distribution of patients with severe, moderate and mild menopausal symptoms were comparable between the two groups. Following nine menstrual cycles, the incidence of amenorrhea reached 100% in the two groups. HIFU therapy is superior to radiotherapy for ovarian castration in premenopausal females with ER(+)/PR(+) breast cancer subsequent to radical mastectomy in terms of its minimal invasiveness and faster efficacy. HIFU represents a feasible non-surgical approach for ovarian castration.

Low-dose dietary genistein negates the therapeutic effect of tamoxifen in athymic nude mice

The present study examined the effect of dietary genistein, a soy isoflavone, on breast cancer patients who take tamoxifen, an antiestrogen treatment, using a preclinical model. The interaction of various doses of genistein with tamoxifen on the growth of estrogen receptor-positive breast cancer MCF-7 cells was investigated by subcutaneously injecting MCF-7 cells into the flank of ovariectomized athymic mice. Animals were randomized into eight experimental groups with 10-13 mice per group: control (C), estrogen (E) (0.08 mg E implant), tamoxifen (T) (3 mg T implant), estrogen + tamoxifen (E + T), tamoxifen + 500 p.p.m. genistein (T + G500), estrogen + tamoxifen + 250 p.p.m. genistein (E + T + G250), estrogen + tamoxifen + 500 p.p.m. genistein (E + T + G500) and estrogen + tamoxifen + 1000 p.p.m. genistein (E + T + G1000). Treatment of tamoxifen significantly reduced the estrogen-induced MCF-7 tumor prevalence and tumor size. This inhibitory effect of tamoxifen was significantly negated by the low doses of dietary genistein (250 and 500 p.p.m.), whereas the 1000 p.p.m. genistein did not have the same effect. Cells harvested from tamoxifen-treated tumors retained estrogen responsiveness of their progenitor MCF-7 cells, indicating that the abrogating effect of genistein on tamoxifen-treated tumor growth was not caused by a diminished tamoxifen response but directly by genistein. The low doses of dietary genistein abrogated the inhibitory effect of tamoxifen potentially by acting on the tumor cell proliferation/apoptosis ratio and the messenger RNA (mRNA) expression of cyclin D1 in addition to regulating the mRNA expression of progesterone receptor. Therefore, data from the current study suggest that caution is warranted regarding the consumption of dietary genistein by breast cancer patients while on tamoxifen therapy.

The role of hormonal ovarian ablation in adjuvant treatment of premenopausal breast cancer

Introduction. Breast cancer is the most frequent malignant disease in women with about 25% compared to all malignant tumours. Chemotherapy, antiestrogen and ovarian ablation/ supression present effective adjuvant approach for premenopausal women diagnosed with hormonal depended, operable breast cancer. Objective. To evaluate benefits of combined chemo/hormonal therapy that is undutiful, but optimal application has not yet been clearly determined. Methods. Thirty-six women were divided into three therapy groups. The first group (13 women) was treated with six cycles of adjuvant FAC chemotherapy followed by regular check-ups; the second group (13 women) after six cycles of adjuvant FAC chemotherapy continued treatment with a two-year application of goserelin given by subcutaneous injections (FAC-Z); the third group (10 women), after six cycles of adjuvant FAC chemotherapy continued with once per month application of gorselin for two years and a daily application of 20 mg tamoxifen for five years (FAC-Z-T). The length of overall disease free period and survival were analyzed in all three groups. Results. The benefit of LH-RH analogues in premenopausal women with hormone-dependent breast cancer was found to be low, and probably limited to smaller subgroups of patients, possibly such as those with either both steroid receptors positive (ER and PR) or those with an extremely high level of steroid receptors. In our paper, analyses of such subgroups could not been performed due to a small sample of patients. The effect of therapy is better in patients, who developed amenorrhoea, regardless of the type of later hormonal therapy. Conclusion. Ovarial ablation, whatever the method, should be probably applied as early as possible within the treatment of early breast cancer, especially in patients in whom chemotherapy induced amenorrhoea is not expected, i.e. in very young female patients.

Dosing of zoledronic acid throughout the treatment continuum in breast cancer

Several bisphosphonates including zoledronic acid (ZOL) are approved for treating bone metastases from breast cancer (BC). Recent trials demonstrated that ZOL prevents bone loss and reduces disease recurrence in early BC. This review uses pharmacodynamic, efficacy, and safety data from phase III trials of ZOL in early through metastatic BC to evaluate the dosing regimens used in each setting. The dosing frequencies of ZOL in early stage versus metastatic BC (4 mg 2--4 times per year versus monthly) are based on the respective levels of bone resorption and tumor burden. Data from ongoing clinical trials suggest that monthly dosing facilitates potential synergy between ZOL and chemotherapy in intermediate-risk BC and during neoadjuvant therapy. Overall, available data indicate that treatment with ZOL at appropriate intervals determined by disease characteristics helps attain key therapeutic goals in BC--maintaining skeletal integrity, reducing disease recurrence, and improving clinical outcomes.

Aromatase inhibitors in breast cancer

Estrogens play important roles in breast cancer development and progression. In postmenopausal women, traditional endocrine therapies such as tamoxifen have sought to inhibit estrogen action by targeting the estrogen receptor itself. However, newer treatments are evolving that target estrogen production in postmenopausal tissues through inhibition of the aromatase enzyme. Clinical data demonstrate that these aromatase inhibitors are superior to tamoxifen as adjuvant therapy for breast cancer and have now replaced tamoxifen as first line therapy in a number of treatment regimens for postmenopausal breast cancer patients.

Thymic involution and immune reconstitution

Chronic thymus involution associated with aging results in less efficient T-cell development and decreased emigration of naïve T cells to the periphery. Thymic decline in the aged is linked to increased morbidity and mortality in a wide range of clinical settings. Negative consequences of these effects on global health make it of paramount importance to understand the mechanisms driving thymic involution and homeostatic processes across the lifespan. There is growing evidence that thymus tissue is plastic and that the involution process might be therapeutically halted or reversed. We present here progress on the exploitation of thymosuppressive and thymostimulatory pathways using factors such as keratinocyte growth factor, interleukin 7 or sex steroid ablation for therapeutic thymus restoration and peripheral immune reconstitution in adults.

Luteinizing hormone-releasing hormone enhances T cell recovery following allogeneic bone marrow transplantation

Posttransplant immunodeficiency, specifically a lack of T cell reconstitution, is a major complication of allogeneic bone marrow transplantation. This immunosuppression results in an increase in morbidity and mortality from infections and very likely contributes to relapse. In this study, we demonstrate that sex steroid ablation using leuprolide acetate, a luteinizing hormone-releasing hormone agonist (LHRHa), increases the number of lymphoid and myeloid progenitor cells in the bone marrow and developing thymocytes in the thymus. Although few differences are observed in the peripheral myeloid compartments, the enhanced thymic reconstitution following LHRHa treatment and allogeneic bone marrow transplantation leads to enhanced peripheral T cell recovery, predominantly in the naive T cell compartment. This results in an increase in T cell function in vivo and in vitro. Graft-versus-host-disease is not exacerbated by LHRHa treatment and graft-versus-tumor activity is maintained. Because LHRHa allows for reversible (and temporary) sex steroid ablation, has a strong safety profile, and has been clinically approved for diseases such as prostate and breast cancer, this drug treatment represents a novel therapeutic approach to reversal of thymic atrophy and enhancement of immunity following immunosuppression.

Strategies for reconstituting and boosting T cell-based immunity following haematopoietic stem cell transplantation: pre-clinical and clinical approaches

Poor immune recovery is characteristic of bone marrow transplantation and leads to high levels of morbidity and mortality. The primary underlying cause is a compromised thymic function, resulting from age-induced atrophy and further compounded by the damaging effects of cytoablative conditioning regimes on thymic epithelial cells (TEC). Several strategies have been proposed to enhance T cell reconstitution. Some, such as the use of single biological agents, are currently being tested in clinical trials. However, a more rational approach to immune restoration will be to leverage the evolving repertoire of new technologies. Specifically, the combined targeting of TEC, thymocytes and peripheral T cells, together with the bone marrow niches, promises a more strategic clinical therapeutic platform.

Enhanced immune system regeneration in humans following allogeneic or autologous hemopoietic stem cell transplantation by temporary sex steroid blockade

PURPOSE

To determine if temporarily blocking sex steroids prior to stem cell transplantation can increase thymus function and thus enhance the rate of T cell regeneration.

EXPERIMENTAL DESIGN

This was a pilot study of luteinizing hormone-releasing hormone agonist (LHRH-A) goserelin given 3 weeks prior to allogeneic or autologous hemopoietic stem cell transplantation and administered up to 3 months posttransplantation. Patients (with or without LHRH-A administration) were assessed from 1 week to 12 months posttransplantation for multiple immunologic variables by flow cytometry (particularly naïve T cells), quantitative PCR to assess T-cell receptor excision circle levels (as a correlate of thymus function), CDR3 length analysis to determine the variability of the TCR repertoire, and in vitro assays to determine functional T cell responses.

RESULTS

LHRH-A administration prior to stem cell transplantation significantly increased neutrophil and lymphocyte numbers within the first month of posttransplantation. Most importantly, total and naïve CD4(+) T cell regeneration together with T-cell receptor excision circle production, T cell repertoire regeneration, and peripheral T cell function were also significantly enhanced at multiple time points posttransplant. In addition, an increase in disease-free survival (P = 0.04) was seen in the autologous setting. Although LHRH-A administration increased T cell responses in vitro, it did not exacerbate graft-versus-host disease in the allogeneic setting.

CONCLUSIONS

This study provides an important new approach to the improvement of immune reconstitution in patients undergoing hemopoietic stem cell transplantation and may have generic applications in many T cell-based disorders.

Heterogeneity of breast cancer and implications of adjuvant chemotherapy

Historically, in selecting adjuvant chemotherapy for patients with breast cancer, anatomy, including tumor size and nodal status, has played the primary role. As a result of analyses of genomic and clinical data, breast cancers are now thought to be a family of diseases. Major subtypes of breast cancer include HER-2 positive disease, basal-like or triple negative tumors, and at least two types of hormonally sensitive cancers. Using the nomenclature developed in the gene expression array studies, these two types are often referred to as luminal A and luminal B. Estrogen receptor negative tumors relapse earlier than estrogen receptor positive tumors. In general, estrogen receptor negative cancers are also more responsive to chemotherapy. In contrast, estrogen positive tumors appear to be somewhat less responsive to chemotherapy, but endocrine therapy can be of substantial benefit in decreasing the risk of disease recurrence. Women with HER-2 positive disease derive significant benefit with the use of trastuzumab. The role of chemotherapy in preventing disease recurrence in patients with estrogen receptor positive tumors is being reevaluated. Recent data suggests that chemotherapy has the greatest benefit in those patients with estrogen receptor positive cancers whose tumors are HER-2 positive disease, weakly ER positive, and/or have high nuclear grade. In the future, breast cancer treatment will be more targeted to the tumor and tailored to the individual with the use of genomic and clinical data.

Treatment of human epidermal growth factor receptor 2-overexpressing breast cancer xenografts with multiagent HER-targeted therapy

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is a member of the HER signaling pathway. HER inhibitors partially block HER signaling and tumor growth in preclinical breast cancer models. We investigated whether blockade of all HER homo- and heterodimer pairs by combined treatment with several inhibitors could more effectively inhibit tumor growth in such models.

METHODS

Mice carrying xenograft tumors of HER2-overexpressing MCF7/HER2-18 (HER2-transfected) or BT474 (HER2-amplified) cells were treated with estrogen supplementation or estrogen withdrawal, alone or combined with tamoxifen. One to three HER inhibitors (pertuzumab, trastuzumab, or gefitinib) could also be added (n > or = 8 mice per group). Tumor volumes, HER signaling, and tumor cell proliferation and apoptosis were assessed. Results were analyzed with the t test or Wilcoxon rank sum test and survival analysis methods. All statistical tests were two-sided.

RESULTS

Median time to tumor progression was 21 days for mice receiving estrogen and 28 days for mice receiving estrogen and pertuzumab (difference = 7 days; P = .001; hazard ratio [HR] of progression in mice receiving estrogen and pertuzumab versus mice receiving estrogen = 0.27, 95% confidence interval [CI] = 0.09 to 0.77). Addition of gefitinib and trastuzumab to estrogen and pertuzumab increased this time to 49 days (difference = 21 days; P = .004; HR of progression = 0.28, 95% CI = 0.10 to 0.76). MCF7/HER2-18 tumors disappeared completely and did not progress (for > or = 189 days) after combination treatment with pertuzumab, trastuzumab, and gefitinib plus tamoxifen (19 of 20 mice) or plus estrogen withdrawal (14 of 15 mice). Both combination treatments induced apoptosis and blocked HER signaling and proliferation in tumor cells better than any single agent or dual combination. All BT474 tumors treated with pertuzumab, trastuzumab, and gefitinib disappeared rapidly, regardless of endocrine therapy, and no tumor progression was observed for 232 days.

CONCLUSION

Combined treatment with gefitinib, trastuzumab, and pertuzumab to block signals from all HER homo- and heterodimers inhibited growth of HER2-overexpressing xenografts statistically significantly better than single agents and dual combinations.

Inadvertent Use of Aromatase Inhibitors in Patients with Breast Cancer with Residual Ovarian Function: Cases and Lessons

Aromatase inhibitors (AIs) are important adjunctive therapy for postmenopausal women with hormone receptor-positive, early-stage breast cancer. At the present time, AIs have no role for the management of breast cancer in premenopausal women. We report on several cases of the inadvertent use of AI therapy among women with residual ovarian function. A common experience in these cases was the onset of chemotherapy-related amenorrhea before initiation of AI therapy, which confounded assessment of true menopausal status. We believe clinicians should be aware of the potential ovarian reserve among women with treatment-related amenorrhea so as to avoid use of AI therapy in patients in whom there is uncertainty about menopausal status.