Tumour markers predictive of successful treatment of breast cancer with primary endocrine therapy in patients over 70 years old: a prospective study

An observational study investigating failure of primary endocrine therapy for operable breast cancer in the elderly

BACKGROUND

Elderly patients are more likely to have oestrogen receptor positive cancers that can be treated without surgery with primary endocrine therapy (PET). Few studies have sought to identify predictors of failure of PET and so the aim of this study was to evaluate treatment failures in elderly breast cancer patients treated with PET and to determine predictors of failure.

METHODS

A retrospective observational study was performed on consecutive patients with ER-positive early stage breast cancer treated with PET between 2005 and 2015 in the three breast units in the North East of England. The primary outcome measure was treatment failure and secondary outcome measure was disease progression.

RESULTS

488 patients were included with mean follow-up 31 months (SD 23). Overall, 206 patients were still alive with their disease controlled at the end of follow-up, 219 had died with their disease controlled and 63 (12%) experienced treatment failure. Younger age [SHR 0.96 (95% CI 0.94-0.99) p 0.013], larger tumours [SHR 1.03 (1.01-1.06) p 0.015], grade 3 cancers [SHR 3.58 (1.93-6.63) p < 0.001] and axillary lymph node metastases [SHR 1.93 (1.06-3.52) p 0.030] were all independent predictors of treatment failure. Disease progression was reported in 86 (17.6%) of patients.

CONCLUSIONS

This is the largest retrospective series evaluating PET treatment failure. Clear predictors of failure have been identified, which can be used to facilitate treatment decision making. These results support previous analyses, further validating our results.

Overcoming endocrine resistance in metastatic breast cancer: Current evidence and future directions

About 75% of all breast cancers are estrogen receptor (ER)-positive. They generally have a more favorable clinical behavior, prognosis, and pattern of recurrence, and endocrine therapy forms the backbone of treatment. Anti-estrogens (such as tamoxifen and fulvestrant) and aromatase inhibitors (such as anastrozole, letrozole, and exemestane) can effectively control the disease and induce tumor responses in a large proportion of patients. However, the majority of patients progress during endocrine therapy (acquired resistance) and a proportion of patients may fail to respond to initial therapy (de novo resistance). Endocrine resistance is therefore of clinical concern and there is great interest in strategies that delay or circumvent it. A deeper knowledge of the molecular mechanisms that drive endocrine resistance has recently led to development of new strategies that have the promise to effectively overcome it. Many resistance mechanisms have been described, and the crosstalk between ER and growth factor receptor signaling pathways seems to represent one of the most relevant. Compounds that are able to inhibit key elements of these pathways and restore endocrine sensitivity have been studied and more are currently under development. The aim of this review is to summarize the molecular pathophysiology of endocrine resistance in breast cancer and its impact on current clinical management.

Comparison of tamoxifen and letrozole response in mammary preneoplasia of ER and aromatase overexpressing mice defines an immune-associated gene signature linked to tamoxifen resistance

Response to breast cancer chemoprevention can depend upon host genetic makeup and initiating events leading up to preneoplasia. Increased expression of aromatase and estrogen receptor (ER) is found in conjunction with breast cancer. To investigate response or resistance to endocrine therapy, mice with targeted overexpression of Esr1 or CYP19A1 to mammary epithelial cells were employed, representing two direct pathophysiological interventions in estrogen pathway signaling. Both Esr1 and CYP19A1 overexpressing mice responded to letrozole with reduced hyperplastic alveolar nodule prevalence and decreased mammary epithelial cell proliferation. CYP19A1 overexpressing mice were tamoxifen sensitive but Esr1 overexpressing mice were tamoxifen resistant. Increased ER expression occurred with tamoxifen resistance but no consistent changes in progesterone receptor, pSTAT3, pSTAT5, cyclin D1 or cyclin E levels in association with response or resistance were found. RNA-sequencing (RNA-seq) was employed to seek a transcriptome predictive of tamoxifen resistance using these models and a second tamoxifen-resistant model, BRCA1 deficient/Trp53 haploinsufficient mice. Sixty-eight genes associated with immune system processing were upregulated in tamoxifen-resistant Esr1- and Brca1-deficient mice, whereas genes related to aromatic compound metabolic process were upregulated in tamoxifen-sensitive CYP19A1 mice. Interferon regulatory factor 7 was identified as a key transcription factor regulating these 68 immune processing genes. Two loci encoding novel transcripts with high homology to human immunoglobulin lambda-like polypeptide 1 were uniquely upregulated in the tamoxifen-resistant models. Letrozole proved to be a successful alternative to tamoxifen. Further study of transcriptional changes associated with tamoxifen resistance including immune-related genes could expand our mechanistic understanding and lead to biomarkers predictive of escape or response to endocrine therapies.

Management of operable primary breast cancer in older women

A considerable number of breast cancer diagnoses are made in older women. Differing physiological needs of older patients and biology of tumors compared with younger patients may alter treatment options between surgery and nonsurgical primary approaches. Adjuvant therapies may benefit these patients; however, concerns about toxicity and physical demands of treatment may affect patient choice regarding treatment. Furthermore, quality of life may be more important to the older individual than curative treatment alone. Growing evidence is emerging for employing Comprehensive Geriatric Assessment to determine other factors that may contribute to treatment decision-making in the older population. The way geriatric oncology is delivered varies, bringing the importance of the multidisciplinary team to the forefront of care delivery in this age group. Future research in this area should include combined consideration of tumor biology and geriatric needs.

Clinical response to primary letrozole therapy in elderly patients with early breast cancer: possible role for p53 as a biomarker

Primary tamoxifen therapy has been widely used to treat elderly women with ER-positive breast cancer in the past. Aromatase inhibitors may be more beneficial than tamoxifen when used as primary endocrine therapy in elderly patients. We aimed to retrospectively evaluate a series of elderly women with ER-positive breast cancer treated with primary letrozole therapy as sole therapy with a minimum of 5 years follow up. To identify possible predictive biomarkers a pilot immunohistochemical analysis was performed to assess the expression of PR, HER2, EGFR, BCL2 and p53. A total of 45 women, aged more than 70 years with a diagnosis of ER-positive breast cancer that was treated with primary letrozole therapy were identified. A case note review was undertaken to obtain clinical information. Formalin fixed paraffin embedded tumour tissue from diagnostic core biopsies was available for all patients. Immunohistochemical analysis was performed to establish the protein expression status of p53, PR, HER2, EGFR and BCL2. The mean age of the 45 patients was 87 years (range 70-101). Clinical benefit was seen in 60% of the patients. Median progression free survival was 53 months (95% CI - 34-72) and the median time to progression was 43 months (95% CI - 22-64). BCL2 was expressed in 45/45 (100%); PR in 38/45 (84%); EGFR in 13/45 (28%); HER2 in 9/45 (20%) and p53 in 5/45 (11%) of tissue samples. Positive expression of p53 was associated with poor progression free survival (p = 0.03) in this pilot study. This study demonstrates that letrozole as sole treatment appears to be a suitable treatment option for elderly patients with ER-positive breast cancer who are not fit for, or decline, surgery. The analysis of p53 in a larger study is warranted in order to assess its role as a biomarker in this patient group.

Breast cancer in the elderly: which lessons have we learned?

Management of older breast cancer patients is challenging due to a lack of good quality evidence regarding the role of adjuvant chemotherapy. Older women can benefit as much from adjuvant chemotherapy as younger women, although they have an increased risk of toxicities. Decisions regarding adjuvant chemotherapy should be made based on tumor biology and biological age, rather than chronological age. Geriatrician assessment can detect subtle functional deficits that may impact on the ability of the patient to tolerate chemotherapy; however, implementation of comprehensive geriatric assessment in the oncology setting is challenging. Instead, numerous frailty screening tools are in development. Future advances should incorporate more accurate and efficient means for determining the biological age of elderly breast cancer patients, which will better define the risk:benefit ratio of adjuvant chemotherapy.

Methoxychlor and triclosan stimulates ovarian cancer growth by regulating cell cycle- and apoptosis-related genes via an estrogen receptor-dependent pathway

Methoxychlor and triclosan are emergent or suspected endocrine-disrupting chemicals (EDCs). Methoxychlor [MXC; 1,1,1-trichlor-2,2-bis (4-methoxyphenyl) ethane] is an organochlorine pesticide that has been primarily used since dichlorodiphenyltrichloroethane (DDT) was banned. In addition, triclosan (TCS) is used as a common component of soaps, deodorants, toothpastes, and other hygiene products at concentrations up to 0.3%. In the present study, the potential impact of MXC and TCS on ovarian cancer cell growth and underlying mechanism(s) was examined following their treatments in BG-1 ovarian cancer cells. As results, MXC and TCS induced BG-1 cell growth via regulating cyclin D1, p21 and Bax genes related with cell cycle and apoptosis. A methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay confirmed that the proliferation of BG-1 ovarian cancer cells was stimulated by MXC (10(-6), 10(-7), 10(-8), and 10(-9)M) or TCS (10(-6), 10(-7), 10(-8), and 10(-9)M). Treatment of BG-1 cells with MXC or TCS resulted in the upregulation of cyclin D1 and downregulation of p21 and Bax transcriptions. In addition, the protein level of cyclin D1 was increased by MXC or TCS while p21 and Bax protein levels appeared to be reduced in these cells. Furthermore, MXC- or TCS-induced alterations of these genes were reversed in the presence of ICI 182,780 (10(-7)M), suggesting that the changes in these gene expressions may be regulated by an ER-dependent signaling pathway. In conclusion, the results of our investigation indicate that two potential EDCs, MXC and TCS, may stimulate ovarian cancer growth by regulating cell cycle- and apoptosis-related genes via an ER-dependent pathway.

Primary endocrine therapy as a treatment for older women with operable breast cancer - a comparison of randomised controlled trial and cohort study findings

INTRODUCTION

One third of all breast cancers occur in women over the age of 70. Primary endocrine therapy (PET) is used in some women to minimise morbidity in a population with higher rates of comorbidity and frailty. In the UK up to 40% of women over 70 are treated with PET although there is a high rate of variability of practice between centres reflecting a lack of guidance about case selection.

METHODS

A systematic review of the literature was performed to try and establish if this form of treatment is still valid in modern breast practice.

RESULTS

Six randomised controlled trials (RCTs) and 31 non-randomised studies were deemed eligible. Available data demonstrate an advantage for surgery over PET in terms of disease control and a likely survival benefit in patients with a predicted life expectancy of five years or more. Patients treated only with aromatase inhibitors (AIs) had superior rates of disease control when compared to Tamoxifen.

CONCLUSIONS

Guidelines to aid selection are needed but PET should be reserved for patients with reduced predicted life expectancy (e.g. less than five years), with AIs being preferable over Tamoxifen.

Targeted agents to reverse resistance to endocrine therapy in metastatic breast cancer: where are we now and where are we going?

Endocrine therapy is the most important systemic therapy for hormone receptor positive breast cancer; however, some patients with ER+ breast cancer show intrinsic resistance to endocrine therapy, whereas others develop acquired resistance. Preclinical models have shown that endocrine resistance is associated with enhanced expression of membrane growth factor pathways or activation of various intracellular pathways involved in signal transduction and cell survival. Despite encouraging preclinical data, clinical trials investigating the combination of endocrine therapy with trastuzumab or the TKIs gefitinib, erlotinib and lapatinib have yielded varied results. This may be related to some limitations in the studies conducted so far: lack of appropriate patient selection and stratification based on previous endocrine exposure and/or sensitivity; lack of identification of a molecular biomarker; lack of appropriate clinical endpoints in the trial design. More promising results come from clinical studies which have focused on novel agents such as the mTOR inhibitor everolimus. The two randomized trials (BOLERO-2 and TAMRAD) evaluating everolimus±endocrine therapy in a selected subgroup of HR-positive metastatic breast cancer patients have demonstrated a significant improvement in progression free survival for the combination compared to the endocrine therapy alone. The data reported so far show that the combination of target agents with endocrine therapy is effective in overcoming acquired resistance in patients with hormone receptor positive metastatic breast cancer. However, this therapeutic strategy is not yet a standard treatment for this patients. Application of more rigorous trial design, tumor and patient selection criteria will be important to better understand the complexity of endocrine resistance.

Breast cancer - one term, many entities?

Breast cancer, rather than constituting a monolithic entity, comprises heterogeneous tumors with different clinical characteristics, disease courses, and responses to specific treatments. Tumor-intrinsic features, including classical histological and immunopathological classifications as well as more recently described molecular subtypes, separate breast tumors into multiple groups. Tumor-extrinsic features, including microenvironmental configuration, also have prognostic significance and further expand the list of tumor-defining variables. A better understanding of the features underlying heterogeneity, as well as of the mechanisms and consequences of their interactions, is essential to improve targeting of existing therapies and to develop novel agents addressing specific combinations of features.

Deficiency in trefoil factor 1 (TFF1) increases tumorigenicity of human breast cancer cells and mammary tumor development in TFF1-knockout mice

Although trefoil factor 1 (TFF1; previously named pS2) is abnormally expressed in about 50% of human breast tumors, its physiopathological role in this disease has been poorly studied. Moreover, controversial data have been reported. TFF1 function in the mammary gland therefore needs to be clarified. In this study, using retroviral vectors, we performed TFF1 gain- or loss-of-function experiments in four human mammary epithelial cell lines: normal immortalized TFF1-negative MCF10A, malignant TFF1-negative MDA-MB-231 and malignant TFF1-positive MCF7 and ZR75.1. The expression of TFF1 stimulated the migration and invasion in the four cell lines. Forced TFF1 expression in MCF10A, MDA-MB-231 and MCF7 cells did not modify anchorage-dependent or -independent cell proliferation. By contrast, TFF1 knockdown in MCF7 enhanced soft-agar colony formation. This increased oncogenic potential of MCF7 cells in the absence of TFF1 was confirmed in vivo in nude mice. Moreover, chemically induced tumorigenesis in TFF1-deficient (TFF1-KO) mice led to higher tumor incidence in the mammary gland and larger tumor size compared with wild-type mice. Similarly, tumor development was increased in the TFF1-KO ovary and lung. Collectively, our results clearly show that TFF1 does not exhibit oncogenic properties, but rather reduces tumor development. This beneficial function of TFF1 is in agreement with many clinical studies reporting a better outcome for patients with TFF1-positive breast primary tumors.