Systematic review of LHRH agonists for the adjuvant treatment of early breast cancer

Ovarian suppression for adjuvant treatment of hormone receptor-positive early breast cancer

BACKGROUND

Approximately 80% of breast cancers amongst premenopausal women are hormone receptor-positive. Adjuvant endocrine therapy is an integral component of care for hormone receptor-positive breast cancer and in premenopausal women includes oestrogen receptor blockade with tamoxifen, temporary suppression of ovarian oestrogen synthesis by luteinising hormone releasing hormone (LHRH) agonists, and permanent interruption of ovarian oestrogen synthesis with oophorectomy or radiotherapy. Recent international consensus statements recommend single-agent tamoxifen or aromatase inhibitors with ovarian function suppression (OFS) as the current standard adjuvant endocrine therapy for premenopausal women (often preceded by chemotherapy). This review examined the role of adding OFS to another treatment (i.e. chemotherapy, endocrine therapy, or both) or comparing OFS to no further adjuvant treatment.

OBJECTIVES

To assess effects of OFS for treatment of premenopausal women with hormone receptor-positive early breast cancer.

SEARCH METHODS

For this review update, we searched the Specialised Register of the Cochrane Breast Cancer Group, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 8), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and ClinicalTrials.gov on 26 September 2019. We screened the reference lists of related articles, contacted trial authors, and applied no language restrictions.

SELECTION CRITERIA

We included all randomised trials assessing any method of OFS, that is, oophorectomy, radiation-induced ovarian ablation, or LHRH agonists, as adjuvant treatment for premenopausal women with early-stage breast cancer. We included studies that compared (1) OFS versus observation, (2) OFS + chemotherapy versus chemotherapy, (3) OFS + tamoxifen versus tamoxifen, and (4) OFS + chemotherapy + tamoxifen versus chemotherapy + tamoxifen.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias and certainty of evidence using the GRADE approach. Hazard ratios (HRs) were derived for time-to-event outcomes, and meta-analysis was performed using a fixed-effect model. The primary outcome measures were overall survival (OS) and disease-free survival (DFS). Toxicity, contralateral breast cancer, and second malignancy were represented as risk ratios (RRs), and quality of life data were extracted when provided.

MAIN RESULTS

This review update included 15 studies involving 11,538 premenopausal women with hormone receptor-positive early breast cancer; these studies were conducted from 1978 to 2014. Some of these treatments are not current standard of care, and early studies did not assess HER2 receptor status. Studies tested OFS versus observation (one study), OFS plus chemotherapy versus chemotherapy (six studies), OFS plus tamoxifen versus tamoxifen (six studies), and OFS plus chemotherapy and tamoxifen versus chemotherapy and tamoxifen (two studies). Of those studies that reported the chemotherapy regimen, an estimated 72% of women received an anthracycline. The results described below relate to the overall comparison of OFS versus no OFS. High-certainty evidence shows that adding OFS to treatment resulted in a reduction in mortality (hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.78 to 0.94; 11 studies; 10,374 women; 1933 reported events). This treatment effect was seen when OFS was added to observation, to tamoxifen, or to chemotherapy and tamoxifen. The effect on mortality was not observed when OFS was added to chemotherapy without tamoxifen therapy (HR 0.95, 95% CI 0.82 to 1.09; 5 studies; 3087 women; median follow-up: range 7.7 to 12.1 years). The addition of OFS resulted in improved DFS (HR 0.83, 95% CI 0.77 to 0.90; 10 studies; 8899 women; 2757 reported events; high-certainty evidence). The DFS treatment effect persisted when OFS was added to observation, to tamoxifen, and to chemotherapy and tamoxifen. The effect on DFS was reduced when OFS was added to chemotherapy without tamoxifen therapy (HR 0.90, 95% CI 0.79 to 1.01; 5 studies; 2450 women). Heterogeneity was low to moderate across studies for DFS and OS (respectively). Evidence suggests that adding OFS slightly increases the incidence of hot flushes (grade 3/4 or any grade; risk ratio (RR) 1.60, 95% CI 1.41 to 1.82; 6 studies; 5581 women; low-certainty evidence, as this may have been under-reported in these studies). Two other studies that could not be included in the meta-analysis reported a higher number of hot flushes in the OFS group than in the no-OFS group. Seven studies involving 5354 women collected information related to mood; however this information was reported as grade 3 or 4 depression, anxiety, or neuropsychiatric symptoms, or symptoms were reported without the grade. Two studies reported an increase in depression, anxiety, and neuropsychiatric symptoms in the OFS group compared to the no-OFS group, and five studies indicated an increase in anxiety in both treatment groups (but no difference between groups) or no difference overall in symptoms over time or between treatment groups. A single study reported bone health as osteoporosis (defined as T score < -2.5); this limited evidence suggests that OFS increases the risk of osteoporosis compared to no-OFS at median follow-up of 5.6 years (RR 1.16, 95% CI 1.10 to 28.82; 2011 women; low-certainty evidence). Adding OFS to treatment likely reduces the risk of contralateral breast cancer (HR 0.75, 95% CI 0.57 to 0.97; 9 studies; 9138 women; moderate-certainty evidence). Quality of life was assessed in five studies; four studies used validated tools, and the fifth study provided no information on how data were collected. Two studies reported worse quality of life indicators (i.e. vaginal dryness, day and night sweats) for women receiving OFS compared to those in the no-OFS group. The other two studies indicated worsening of symptoms (e.g. vasomotor, gynaecological, vaginal dryness, decline in sexual interest, bone and joint pain, weight gain); however these side effects were reported in both OFS and no-OFS groups. The study that did not use a validated quality of life tool described no considerable differences between groups.

AUTHORS' CONCLUSIONS

This review found evidence that supports adding OFS for premenopausal women with early, hormone receptor-positive breast cancers. The benefit of OFS persisted when compared to observation, and when added to endocrine therapy (tamoxifen) or chemotherapy and endocrine therapy (tamoxifen). The decision to use OFS may depend on the overall risk assessment based on tumour and patient characteristics, and may follow consideration of all side effects that occur with the addition of OFS.

Evaluating triptorelin as a treatment option for breast cancer

Introduction: Triptorelin is a luteinizing hormone-releasing hormone analog (LH-RHa) inducing ovarian function suppression (OFS). It is approved by FDA and EMA in association with tamoxifen or aromatase inhibitor (AI) and with fulvestrant and palbociclib in premenopausal women with hormone receptor (HR)-positive breast cancer. Its potential role to preserve ovarian function during chemotherapy has also been recently clarified. Areas covered: Several studies have investigated the role of adding OFS to tamoxifen and aromatase inhibitors as adjuvant treatment in early breast cancer. The addition of triptorelin is not free from adverse events as the combination with tamoxifen and exemestane resulted in an increase of endocrine-deprivation symptoms. Clinical trials have explored the combination of LH-RHa with chemotherapy in fertility preservation, demonstrating no detrimental effect on patients' oncological outcome. This is all discussed in this evaluation. Expert opinion: Triptorelin represents a standard-of-care in premenopausal women with HR-positive breast cancer and in some cases of male breast cancer. In the adjuvant setting, a personalized approach is required to combine LH-RHa with the right partner considering the risk of recurrence and the toxicity profile. LH-RHa may be offered to breast cancer patients in the hope of reducing the likelihood of chemotherapy-induced ovarian insufficiency.

Data Perturbation Independent Diagnosis and Validation of Breast Cancer Subtypes Using Clustering and Patterns

Molecular stratification of disease based on expression levels of sets of genes can help guide therapeutic decisions if such classifications can be shown to be stable against variations in sample source and data perturbation. Classifications inferred from one set of samples in one lab should be able to consistently stratify a different set of samples in another lab. We present a method for assessing such stability and apply it to the breast cancer (BCA) datasets of Sorlie et al. 2003 and Ma et al. 2003. We find that within the now commonly accepted BCA categories identified by Sorlie et al. Luminal A and Basal are robust, but Luminal B and ERBB2+ are not. In particular, 36% of the samples identified as Luminal B and 55% identified as ERBB2+ cannot be assigned an accurate category because the classification is sensitive to data perturbation. We identify a “core cluster” of samples for each category, and from these we determine “patterns” of gene expression that distinguish the core clusters from each other. We find that the best markers for Luminal A and Basal are (ESR1, LIV1, GATA-3) and (CCNE1, LAD1, KRT5), respectively. Pathways enriched in the patterns regulate apoptosis, tissue remodeling and the immune response. We use a different dataset (Ma et al. 2003) to test the accuracy with which samples can be allocated to the four disease subtypes. We find, as expected, that the classification of samples identified as Luminal A and Basal is robust but classification into the other two subtypes is not.

Gonadotropin-releasing hormone type II antagonist induces apoptosis in MCF-7 and triple-negative MDA-MB-231 human breast cancer cells in vitro and in vivo

Introduction

Triple-negative breast cancer does not express estrogen and progesterone receptors, and no overexpression/amplification of the HER2-neu gene occurs. Therefore, this subtype of breast cancer lacks the benefits of specific therapies that target these receptors. Today chemotherapy is the only systematic therapy for patients with triple-negative breast cancer. About 50% to 64% of human breast cancers express receptors for gonadotropin-releasing hormone (GnRH), which might be used as a target. New targeted therapies are warranted. Recently, we showed that antagonists of gonadotropin-releasing hormone type II (GnRH-II) induce apoptosis in human endometrial and ovarian cancer cells in vitro and in vivo. This was mediated through activation of stress-induced mitogen-activated protein kinases (MAPKs) p38 and c-Jun N-terminal kinase (JNK), followed by activation of proapoptotic protein Bax, loss of mitochondrial membrane potential, and activation of caspase-3. In the present study, we analyzed whether GnRH-II antagonists induce apoptosis in MCF-7 and triple-negative MDA-MB-231 human breast cancer cells that express GnRH receptors. In addition, we ascertained whether knockdown of GnRH-I receptor expression affects GnRH-II antagonist-induced apoptosis and apoptotic signaling.

Methods

Induction of apoptosis was analyzed by measurement of the loss of mitochondrial membrane potential. Apoptotic signaling was measured with quantification of activated MAPK p38 and caspase-3 by using the Western blot technique. GnRH-I receptor protein expression was inhibited by using the antisense knockdown technique. In vivo experiments were performed by using nude mice bearing xenografted human breast tumors.

Results

We showed that treatment of MCF-7 and triple-negative MDA-MB-231 human breast cancer cells with a GnRH-II antagonist results in apoptotic cell death in vitro via activation of stress-activated MAPK p38 and loss of mitochondrial membrane potential. In addition, we showed GnRH-II antagonist-induced activation of caspase-3 in MDA-MB-231 human breast cancer cells. After knockdown of GnRH-I receptor expression, GnRH-II antagonist-induced apoptosis and apoptotic signaling was only slightly reduced, indicating that an additional pathway mediating the effects of GnRH-II antagonists may exist. The GnRH-I receptor seems not to be the only target of GnRH-II antagonists. The antitumor effects of the GnRH-II antagonist could be confirmed in nude mice. The GnRH-II antagonist inhibited the growth of xenotransplants of human breast cancers in nude mice completely, without any apparent side effects.

Conclusions

GnRH-II antagonists seem to be suitable drugs for an efficacious and less-toxic endocrine therapy for breast cancers, including triple-negative breast cancers.

LHRH agonists for adjuvant therapy of early breast cancer in premenopausal women

BACKGROUND

Approximately 60% of breast cancers amongst premenopausal women express the nuclear oestrogen receptor (ER+ breast cancer). Adjuvant endocrine therapy is an integral component of care for ER+ breast cancer, exerting its effect by reducing the availability of oestrogen to micrometastatic tumour cells. Endocrine strategies in premenopausal women include oestrogen receptor blockade with tamoxifen, temporary suppression of ovarian oestrogen synthesis by luteinising hormone releasing hormone (LHRH) agonists, or permanent interruption of ovarian oestrogen synthesis with oophorectomy or radiotherapy. Aromatase inhibitors are also available with concurrent suppression of ovarian oestrogen synthesis, either through LHRH agonists, surgery, or radiotherapy. Chemotherapy can also have an endocrine action in premenopausal women by interrupting ovarian oestrogen production, either temporarily or permanently. International consensus statements recommend single agent tamoxifen as the current standard adjuvant endocrine therapy for premenopausal women (often preceded by chemotherapy), and the role of LHRH agonists remains under active investigation.

OBJECTIVES

To assess LHRH agonists as adjuvant therapy for women with early breast cancer.

SEARCH STRATEGY

The Cochrane Breast Cancer Group Specialised Register was searched on 19 February 2009. This register incorporates references from CENTRAL (The Cochrane Library) (to 2002), MEDLINE (1966 to July 2008), EMBASE (until 2002); and handsearches of abstracts from the San Antonio Breast Cancer Symposium, American Society of Clinical Oncology Annual Meeting, and the Clinical Oncological Society of Australia Annual Meeting. MEDLINE references (from August 2008 to 19th February 2009) were checked by the authors. The reference lists of related reviews were checked. A final check of the list of trials maintained by the Early Breast Cancer Trialists' Collaborative Group was made in January 2008.

SELECTION CRITERIA

All randomised trials assessing LHRH agonists as adjuvant treatment in premenopausal women with early stage breast cancer were included. Specifically, we included trials that compared:(A) LHRH agonists (experimental arm) versus another treatment;(B) LHRH agonists + anti-oestrogen (experimental arm) versus another treatment;(C) LHRH agonists + chemotherapy (experimental arm) versus another treatment;(D) LHRH agonists + anti-oestrogen + chemotherapy (experimental arm) versus another treatment.

DATA COLLECTION AND ANALYSIS

Data were collected from trial reports. We reported estimates for the differences between treatments on recurrence free survival, overall survival, toxicity and quality of life using data available in the reports of each trial. Meta-analyses were not performed because of variability in the reporting of the trials.

MAIN RESULTS

We identified 14 randomised trials that involved over 13,000 premenopausal women with operable breast cancer, most of whom were ER+. The numbers of trials making the different comparisons were:(A) i. LHRH versus tamoxifen (three trials),ii. LHRH versus chemotherapy (four trials);(B) i. LHRH + tamoxifen versus tamoxifen (two trials),ii. LHRH + tamoxifen versus LHRH (three trials),iii. LHRH + tamoxifen versus chemotherapy (two trials),iv. LHRH + aromatase inhibitor versus LHRH + tamoxifen (one trial);(C) i. LHRH + chemotherapy versus LHRH (one trial),ii. LHRH + chemotherapy versus chemotherapy (five trials);(D) LHRH + tamoxifen + chemotherapy versus chemotherapy (three trials).The LHRH agonist in most of these trials was goserelin.For most of the treatment comparisons there are too few trials, too few randomised patients, or too little follow up to draw reliable estimates of the relative effects of different treatments.(A) LHRH monotherapy: results suggest that adjuvant LHRH agonist monotherapy is similar to older chemotherapy protocols (eg. CMF) in terms of recurrence-free and overall survival in ER+ patients. There are insufficient data to compare LHRH agonist monotherapy to tamoxifen alone, but available results suggest that these treatments are comparable in terms of recurrence-free survival.(B) LHRH + anti-oestrogen therapy: there are insufficient data to compare the combination of an LHRH agonist plus tamoxifen to tamoxifen alone. Results suggest that the LHRH agonist plus tamoxifen combination may be superior to an LHRH agonist alone or to chemotherapy alone, but the chemotherapy protocols tested are outdated. The data comparing LHRH agonists plus aromatase inhibitors to LHRH agonists plus tamoxifen are currently inconclusive.(C) LHRH + chemotherapy: there are insufficient data to compare the LHRH + chemotherapy combination to an LHRH agonist alone, although results from a single study suggest comparable efficacy in ER+ patients. There is a trend towards improved recurrence-free and overall survival in patients who received an LHRH agonist plus chemotherapy combination in comparison to chemotherapy alone.(D) LHRH agonist + chemotherapy + tamoxifen: there is a trend towards improved recurrence-free and overall survival in patients who received an LHRH agonist plus tamoxifen plus chemotherapy in comparison to chemotherapy alone.There are insufficient data to assess the effect of the addition of LHRH agonists to the current standard treatment of chemotherapy plus tamoxifen.Endocrine therapy with LHRH agonists appears to have fewer side-effects than the forms of chemotherapy assessed. The optimal duration of LHRH therapy in the adjuvant setting is unclear.

AUTHORS' CONCLUSIONS

Overall, the data from currently published clinical trials of LHRH agonists in the adjuvant setting for premenopausal women with endocrine-sensitive breast cancer are supportive of clinical benefit. Nonetheless, definitive comparisons against current clinical standards of care that include third generation chemotherapy regimens and tamoxifen are required before their place in the adjuvant setting can be properly defined. The authors conclude that the current data strongly support the continuation of current trials that definitively compare a variety of combinations of LHRH agonists and anti-oestrogenic strategies to the current standard of five years of tamoxifen.

LHRH agonists for adjuvant therapy of early breast cancer in premenopausal women

BACKGROUND

Approximately 60% of breast cancer tumours in premenopausal women are hormone sensitive (ER+). These patients may be suitable for hormonal treatment. The goal of hormonal therapy is to reduce the availability of oestrogen to the cancer cell. This can be achieved by blocking oestrogen receptors with drugs such as tamoxifen, suppression of oestrogen synthesis by LHRH agonists, or ovarian ablation either surgically or by radiotherapy. Chemotherapy can also have a hormonal action by inducing amenorrhoea in premenopausal women.

OBJECTIVES

To assess LHRH agonists as adjuvant therapy for women with early breast cancer.

SEARCH STRATEGY

The specialised register of the Cochrane Breast Cancer Group was searched on 19 December 2006. The reference lists of related reviews were checked. A final check of the list of trials maintained by the Early Breast Cancer Trialists' Collaborative Group was made in January 2008.

SELECTION CRITERIA

Randomised trials of LHRH agonist versus LHRH agonist and tamoxifen, LHRH agonist versus chemotherapy, LHRH agonist versus ovarian ablation, or LHRH agonist versus LHRH agonist and chemotherapy, that recruited premenopausal women with early breast cancer.

DATA COLLECTION AND ANALYSIS

Data were collected from trial reports. We report estimates for the differences between treatments on recurrence free survival, overall survival, toxicity and quality of life using data available in the reports of each trial. Meta-analyses were not performed because of variability in the reporting of the trials and the need for more mature data.

MAIN RESULTS

We identified 14 randomised trials, involving nearly 12,000 premenopausal women with operable breast cancer, most of whom were ER+. The LHRH agonist in most of these trials was goserelin. For most of the treatment comparisons there are too few trials, too few randomised patients or too little follow-up to draw reliable estimates of the relative effects of different treatments. Four trials (nearly 5000 women) addressed the integration of LHRH agonists into adjuvant hormonal therapy, showing that a combination of an LHRH agonist and tamoxifen might be better than either alone. Insufficient data are available to inform a choice between tamoxifen and goserelin as sole adjuvant therapy. We included twelve trials (more than 10,000 women) of the integration of LHRH agonists into adjuvant chemo-hormonal therapy. Four trials assessed the effects of an LHRH agonist compared to chemotherapy and three other trials investigated a combination of an LHRH agonist and tamoxifen versus chemotherapy. One trial assessed the effects of adding chemotherapy to an LHRH agonist, five trials compared a combination of an LHRH agonist and chemotherapy versus chemotherapy alone, and three trials compared the combination of LHRH agonist, tamoxifen and chemotherapy versus chemotherapy alone. No trials compared an LHRH agonist containing regimen against chemotherapy and tamoxifen. No significant differences in recurrence free survival or overall survival were found between LHRH agonists, with or without adjuvant tamoxifen, and chemotherapy for premenopausal women with ER+ tumours, but hormonal therapy had fewer distressing side effects. The trials point to reductions in recurrence and death for premenopausal women with ER+ tumours who take LHRH agonists, with or without tamoxifen, along with chemotherapy.

AUTHORS' CONCLUSIONS

For premenopausal women with early breast cancer who are not known to be ER negative, the use of an LHRH agonist, with or without tamoxifen as adjuvant therapy is likely to lead to a reduction in the risk of recurrence and a delay in death. The evidence is insufficient to support the LHRH agonists over chemotherapy, or vice versa, in regard to recurrence free survival and overall survival, but LHRH agonists have fewer or less severe adverse effects. Further follow-up of women in these trials is needed to provide reliable evidence on long term outcomes. Direct randomised comparisons of different durations of LHRH agonists (for example, two years versus longer) and, in the presence of uncertainty, of different LHRH agonists among ER+ or ER unknown premenopausal women are also needed. It is also uncertain how the findings from the CMF-based trials in this review would relate to the use of LHRH agonists with more modern chemotherapy regimens or the comparison of LHRH agonist containing regimens with combinations such as chemotherapy and tamoxifen.

Receptor targeted polymers, dendrimers, liposomes: which nanocarrier is the most efficient for tumor-specific treatment and imaging?

To compare the influence of different characteristics of nanocarriers on the efficacy of chemotherapy and imaging, we designed, characterized, and evaluated three widely used nanocarriers: linear polymer, dendrimer and liposome in vitro and in vivo. These nanocarriers delivered the same anticancer drug (paclitaxel) and/or imaging agent (Cy5.5). A synthetic analog of LHRH peptide targeted to receptors overexpressed on the membrane of cancer cells was attached to the nanocarriers as a tumor targeting moiety. Significant differences were found between various studied non-targeted carriers in their cellular internalization, cytotoxicity, tumor and organ distribution and anticancer efficacy. LHRH peptide substantially enhanced intratumoral accumulation and anticancer efficacy of all delivery systems and minimized their adverse side effects. For the first time, the present study revealed that the targeting of nanocarriers to tumor-specific receptors minimizes the influence of the architecture, composition, size and molecular mass of nanocarriers on the efficacy of imaging and cancer treatment.

Gonadotropin-releasing hormone type II antagonists induce apoptotic cell death in human endometrial and ovarian cancer cells in vitro and in vivo

In human endometrial and ovarian cancers, gonadotropin-releasing hormone type I (GnRH-I), GnRH-II, and their receptors are parts of a negative autocrine regulatory system of cell proliferation. Based on a tumor-specific signal transduction, GnRH-I and GnRH-II agonists inhibit the mitogenic signal transduction of growth factor receptors and related oncogene products associated with tyrosine kinase activity via activation of a phosphotyrosine phosphatase resulting in down-regulation of cancer cell proliferation. Induction of apoptosis is not involved. In this study, we show that treatment of human endometrial and ovarian cancer cells with GnRH-II antagonists results in apoptotic cell death via dose-dependent activation of caspase-3. The antitumor effects of the GnRH-II antagonists could be confirmed in nude mice. GnRH-II antagonists inhibited the growth of xenotransplants of human endometrial and ovarian cancers in nude mice significantly, without any apparent side effects. Thus, GnRH-II antagonists seem to be suitable drugs for an efficacious and less toxic endocrine therapy for endometrial and ovarian cancers.

American Society of Clinical Oncology recommendations on fertility preservation in cancer patients

PURPOSE

To develop guidance to practicing oncologists about available fertility preservation methods and related issues in people treated for cancer.

METHODS

An expert panel and a writing committee were formed. The questions to be addressed by the guideline were determined, and a systematic review of the literature from 1987 to 2005 was performed, and included a search of online databases and consultation with content experts.

RESULTS

The literature review found many cohort studies, case series, and case reports, but relatively few randomized or definitive trials examining the success and impact of fertility preservation methods in people with cancer. Fertility preservation methods are used infrequently in people with cancer.

RECOMMENDATIONS

As part of education and informed consent before cancer therapy, oncologists should address the possibility of infertility with patients treated during their reproductive years and be prepared to discuss possible fertility preservation options or refer appropriate and interested patients to reproductive specialists. Clinician judgment should be employed in the timing of raising this issue, but discussion at the earliest possible opportunity is encouraged. Sperm and embryo cryopreservation are considered standard practice and are widely available; other available fertility preservation methods should be considered investigational and be performed in centers with the necessary expertise.

CONCLUSION

Fertility preservation is often possible in people undergoing treatment for cancer. To preserve the full range of options, fertility preservation approaches should be considered as early as possible during treatment planning.