Phase II trial with letrozole to maximum response as primary systemic therapy in postmenopausal patients with ER/PgR[+] operable breast cancer

Neoadjuvant Therapy: Current Landscape and Future Horizons for ER-Positive/HER2-Negative and Triple-Negative Early Breast Cancer

OPINION STATEMENT

Navigating the complex landscape of breast cancer treatment involves distinct strategies for luminal and triple-negative subtypes. While neoadjuvant chemotherapy historically dominates the approach for aggressive triple-negative tumors, recent evidence highlights the transformative impact of immunotherapy, alongside chemotherapy, in reshaping treatment paradigms. In luminal cancers, endocrine therapy, notably aromatase inhibitors, demonstrates promising outcomes in postmenopausal patients with low-grade luminal A tumors. However, integrating targeted therapies like CDK4/6 inhibitors in neoadjuvant setting remains inconclusive. Identifying predictive factors for treatment response, especially in luminal tumors, poses a challenge, emphasizing the necessity for ongoing research. A multidisciplinary approach, tailored to individual patient profiles, is crucial for maximizing efficacy while minimizing toxicity. As we strive to optimize breast cancer management, a comprehensive understanding of the distinct characteristics and treatment implications of luminal and triple-negative subtypes, including the transformative role of immunotherapy, is essential for informed decision-making and personalized care.

Neo-adjuvant therapies for ER positive/HER2 negative breast cancers: from chemotherapy to hormonal therapy, CDK inhibitors, and beyond

INTRODUCTION

Chemotherapy has been traditionally used as neo-adjuvant therapy in breast cancer for down-staging of locally advanced disease in all sub-types. In the adjuvant setting, genomic assays have shown that a significant proportion of ER positive/HER2 negative patients do not derive benefit from the addition of chemotherapy to adjuvant endocrine therapy. An interest in hormonal treatments as neo-adjuvant therapies in ER positive/HER2 negative cancers has been borne by their documented success in the adjuvant setting. Moreover, cytotoxic chemotherapy is less effective in ER positive/HER2 negative disease compared with other breast cancer subtypes in obtaining pathologic complete responses.

AREAS COVERED

Neo-adjuvant therapies for ER positive/HER2 negative breast cancers and associated biomarkers are reviewed, using a Medline survey. A focus of discussion is the prediction of patients that are unlikely to derive extra benefit from chemotherapy and have the highest probabilities of benefiting from hormonal and other targeted therapies.

EXPERT OPINION

Predictive biomarkers of response to neo-adjuvant chemotherapy and hormonal therapies are instrumental for selecting ER positive/HER2 negative breast cancer patients for each treatment. Chemotherapy remains the standard of care for many of those patients requiring neo-adjuvant treatment, but other neo-adjuvant therapies are increasingly used.

Neoadjuvant endocrine therapy in ER-positive breast cancer: evolution, indication, and tailored treatment strategy

In recent years, endocrine therapy (ET), an effective systemic treatment for the management of estrogen receptor (ER)-positive breast cancers, has regained interest as a neoadjuvant therapy based on evidence that ET can fulfill the aim of neoadjuvant systemic treatment for tumor shrinkage as well as elucidate important clinical information on endocrine sensitivity that enables the prognostication of patients. Moreover, neoadjuvant endocrine therapy (NET) potentially provides an opportunity for early assessment of the clinical efficacy of novel agents. Furthermore, recently reported trials have generated evidence for a more tailored approach for perioperative management of ER-positive breast cancer using clinical and molecular biomarkers, and this has provided a rationale that enables the broadening of clinical indications for NET. This review discusses the current evidence for NET, the evolution of NET trials, clinical indications, and NET-based treatment strategies.

The immune microenvironment characterisation and dynamics in hormone receptor-positive breast cancer before and after neoadjuvant endocrine therapy

BACKGROUND

Oestrogen receptor positive (ER+)/HER-2 negative breast cancer (BC) is considered to be an immunologically cold tumour compared to triple negative breast cancer. Therefore, the tumour microenvironment (TME) of ER+/HER-2 negative BC is understudied. The aim of this project is to investigate the TME and the immune response during neoadjuvant endocrine therapy (NET) and to correlate this with the treatment response in a real life setting.

METHODS

Expression of immune checkpoint receptors and immune cells was examined immunohistochemically, pre- and post-NET in a cohort of 56 ER+/HER-2 negative BC patients. They were treated with tamoxifen (n = 16), an aromatase inhibitor (n = 40) or a combination of an aromatase inhibitor with a PI3K inhibitor (n = 11) for a median duration of 6 months (range 1-32 months). Immunohistochemical staining with monoclonal antibodies for PDL-1, PD-1, TIM-3, LAG-3, CTLA-4, CD4, CD68 and FOXP3 were performed. All staining procedures were done according to validated protocols, and scoring was done by a pathologist specialized in breast cancer. Positivity was defined as staining >1% on TILs. Response to NET was evaluated according to tumour size change on imaging and Ki-67 change.

RESULTS

The median age was 61.02 (37-90) years. Diameter of tumour size decreased with a mean of 8.1 mm (-16 mm to 45 mm) (p < 0.001) during NET and the value of Ki-67 value decreased with a median of 9 after NET (p < 0.001). An increase in PD-L1 expression after NET showed a trend towards significant (p = 0.088) and CD-4+ T cells significantly increased after NET (p = 0.03). A good response to NET defined as a decrease in tumour size and/or decrease of Ki-67 was found to be associated with a longer duration of NET, a change of CD4+ T-cells and a higher number of CD68+ tumour-associated macrophages before the start of NET.

CONCLUSION

The immune microenvironment plays an important role in ER+/HER-2 negative BC. NET influences the composition and functional state of the infiltrating immune cells. Furthermore, changes in the immune microenvironment are also associated with treatment response.

Occult Invasive Lobular Carcinoma Presenting as an Axillary Skin Metastatic Lesion Underwent Neoadjuvant Endocrine Therapy and Surgical Resection: A Case Report and Review of Literature

Introduction

Invasive lobular carcinoma (ILC) is the second most common type of breast cancer accounting for 5–15% of all breast cancer cases. It usually presents with nonspecific signs and symptoms. Occult breast cancer presenting as an axillary mass is rare, with prevalence of 0.3–1%, less likely with isolated cutaneous breast metastasis as a first presentation. There are limited data in the literature on patients who underwent endocrine therapy and complete surgical resection.

Case Presentation

A 54-year-old woman with left axillary skin swelling that had been persisting for 6 years was diagnosed with ILC 18 months ago presenting with an ulcerated axillary skin lesion and was managed with letrozole in another facility as she was estrogen receptor (ER) and progesterone receptor (PR) positive. She received letrozole for 18 months and had a partial response in the form of healing of the ulcer with persistent subcutaneous nodules. Her breast mammogram, ultrasound, and magnetic resonance imaging findings were unremarkable; however, there were few prominent left axillary lymph nodes. A biopsy of the left axillary lymph node was positive for malignancy, consistent with ILC. A skin punch biopsy of the axillary skin lesion showed ILC extending to the dermis with no background breast tissue. The patient underwent left modified radical mastectomy with excision of the left axillary skin lesion. The breast specimen comprised 0.4 mm of ILC as the primary malignancy and nine positive axillary lymph node malignancies. The patient received adjuvant radiotherapy and continued to receive letrozole. There were no signs of complications or recurrence during the follow-up period.

Conclusion

Ulcerated skin lesions in the axilla should raise concerns regarding breast cancer metastasis. In cases of isolated cutaneous breast metastases, surgical excision can be considered in combination with endocrine therapy.

Psychological Distress, Coping Strategies, and Quality of Life in Breast Cancer Patients Under Neoadjuvant Therapy: Protocol of a Systematic Review

Introduction

Women with breast cancer eligible for neoadjuvant therapy (NAT) present a disorder of biopsychosocial variables and alteration of their quality of life. They cope with this changing by adopting psychological adjustment strategies, either passive or active. This systematic review aims to investigate the psychological distress, coping strategies, and quality of life in breast cancer patients under neoadjuvant therapy.

Methods

Cochrane Library, PubMed, ScienceDirect, Scopus, Web of Science, and Wiley Online library represent the databases that were searched to identify relevant published articles until September 27, 2021. Full-text published articles, written in English and assessing the main outcomes (namely: psychological distress, coping strategies, and quality of life) in women with breast cancer under NAT will be included. Also, we will integrate papers dealing with the related bio psychosocial variables to the main variables. The paper selection, data extraction, and quality assessment of selected studies will be performed independently by two researchers, and disagreements will be resolved through discussions. We will bring together the results of all of the included studies to draw conclusions based on the body of evidence. The narrative approach will be adopted to analyze the results and conclusions extracted and we would perform quantitative groupings if we have similar data.

Ethics and dissemination

Ethical approval is not required as the proposed systematic review will not use primary data. The results of this review will be disseminated through publication in a peer-reviewed journal and conference presentation(s). PROSPERO registration number: CRD42021230300.

Neoadjuvant Endocrine Therapy in Clinical Practice: A Review

Importance

In clinical practice, neoadjuvant endocrine therapy (NET) is rarely used despite being an effective treatment modality able to downstage tumors and facilitate breast-conserving surgery.

Observations

Using data from studies conducted since 2000, we provide readers with a critical in-depth review on clinical aspects related to the application of NET in the treatment of hormone receptor (HR)-positive/ERBB2 (formerly HER2)-negative breast cancer. This includes an overview of patient-selection criteria, regimen choice, treatment duration, evaluation of response by imaging, interpretation of pathology after treatment, and surgical considerations. Areas of controversy include the use of gene-expression tests for patient selection, treatment of premenopausal women, surgical management of the axilla after NET, and adjuvant systemic therapy decision-making, including the use of chemotherapy.

Conclusions and Relevance

NET is an optimal treatment modality for a considerable proportion of postmenopausal women diagnosed with HR-positive tumors. The treatment landscape for HR-positive breast cancer is evolving, with novel agents and the growing use of gene expression profiling to define treatment selection. As such, it is likely that NET use will increase and the practical considerations outlined here will become more important.

Axillary Lymph Node Dissection Rates and Prognosis From Phase III Neoadjuvant Systemic Trial Comparing Neoadjuvant Chemotherapy With Neoadjuvant Endocrine Therapy in Pre-Menopausal Patients With Estrogen Receptor-Positive and HER2-Negative, Lymph Node-Positive Breast Cancer

In this study, we aimed to evaluate axillary lymph node dissection (ALND) rates and prognosis in neoadjuvant chemotherapy (NCT) compare with neoadjuvant endocrine therapy (NET) in estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-), lymph node (LN)-positive, premenopausal breast cancer patients (NCT01622361). The multicenter, phase 3, randomized clinical trial enrolled 187 women from July 5, 2012, to May 30, 2017. The patients were randomly assigned (1:1) to either 24 weeks of NCT including adriamycin plus cyclophosphamide followed by intravenous docetaxel, or NET involving goserelin acetate and daily tamoxifen. ALND was performed based on the surgeon’s decision. The primary endpoint was ALND rate and surgical outcome after preoperative treatment. The secondary endpoint was long-term survival. Among the 187 randomized patients, pre- and post- neoadjuvant systemic therapy (NST) assessments were available for 170 patients. After NST, 49.4% of NCT patients and 55.4% of NET patients underwent mastectomy after treatment completion. The rate of ALND was significantly lower in the NCT group than in the NET group (55.2% vs. 69.9%, P=.046). Following surgery, the NET group showed a significantly higher mean number of removed LNs (14.96 vs. 11.74, P=.003) and positive LNs (4.84 vs. 2.92, P=.000) than the NCT group. The axillary pathologic complete response (pCR) rate was significantly higher in the NCT group (13.8% vs. 4.8%, P=.045) than in the NET group. During a median follow-up of 67.3 months, 19 patients in the NCT group and 12 patients in the NET group reported recurrence. The 5-year ARFS (97.5%vs. 100%, P=.077), DFS (77.2% vs. 84.8%, P=.166), and OS (97.5% vs. 94.7%, P=.304) rates did not differ significantly between the groups. In conclusion, although survival did not differ significantly, more NCT patients might able to avoid ALND, with fewer LNs removed with lower LN positivity.

The Present and Future of Neoadjuvant Endocrine Therapy for Breast Cancer Treatment

Simple Summary

The treatment of breast cancer has evolved considerably over the last two decades, leading toward individualized disease management. Hormone-sensitive breast cancers constitute the vast majority of cases and endocrine therapy is the mainstay of their treatment. On the other hand, neoadjuvant or pre-surgical treatments provide a number of advantages for tumor management. In this review we will discuss the existing evidence on neoadjuvant endocrine therapy, as well as its possible future indications.

Abstract

Endocrine therapy (ET) has established itself as an efficacious treatment for estrogen receptor-positive (ER+) breast cancers, with a reduction in recurrence rates and increased survival rates. The pre-surgical approach with chemotherapy (NCT) has become a common form of management for large, locally advanced, or high-risk tumors. However, a good response to NCT is not usually expected in ER+ tumors. Good results with primary ET, mainly in elderly women, have encouraged studies in other stages of life, and nowadays neoadjuvant endocrine treatment (NET) has become a useful approach to many ER+ breast cancers. The aim of this review is to provide an update on the current state of art regarding the present and the future role of NET.

Neoadjuvant endocrine therapy in women with operable breast cancer: A retrospective analysis of real-world use

BACKGROUND

A retrospective study of the real-world use of neoadjuvant endocrine therapy (NET) is important for standardizing its role in breast cancer care.

MATERIALS AND METHODS

In a consecutive series of women with operable breast cancer who received NET for ≥28 days, NET objectives, NET outcomes, adjuvant chemotherapy use after NET, and survivals, were examined for the correlation with clinicopathological factors.

RESULTS

NET objectives were for surgery extent reduction in 49 patients, surgery avoidance in 31, and treatment until scheduled surgery in 8. The mean duration of NET was 349.5 (range, 34-1923), 869.8 (range, 36-4859), and 55.8 (range, 39-113) days in the above cohorts (success: 79.6%, 64.5%, and 100%), respectively, with significant difference. In patients of the former two cohorts, better progression-free survival was significantly correlated with stage 0 or I, ductal carcinoma in situ or invasive ductal carcinoma, ≥71% estrogen receptor (ER) positivity, and the surgery extent reduction cohort than the other counterparts. Postoperative chemotherapy use was significantly correlated with lymph node metastasis, a high Ki67 labeling index, lymphovascular invasion, and a high Preoperative Endocrine Prognostic Index, at surgery after NET. Better recurrence-free survival after surgery was significantly correlated with high ER expression after NET and high PgR expression before and after NET.

CONCLUSIONS

NET can help to reduce the surgery extent or to avoid surgery in women with breast cancer of early-stage, ductal carcinoma, or high ER expression. NET may also contribute to appropriate decision of postoperative systemic therapy to improve survivals.

Targeted Neoadjuvant Therapies in HR+/HER2-Breast Cancers: Challenges for Improving pCR

A strong association of pCR (pathological complete response) with disease-free survival or overall survival is clinically desirable. The association of pCR with disease-free survival or overall survival in ER+/HER2-breast cancers following neoadjuvant systemic therapy (NAT) or neoadjuvant endocrine therapy (NET) is relatively low as compared to the other two subtypes of breast cancers, namely triple-negative and HER2+ amplified. On the bright side, a neoadjuvant model offers a potential opportunity to explore the efficacy of novel therapies and the associated genomic alterations, thus providing a rare personalized insight into the tumor's biology and the tumor cells' response to the drug. Several decades of research have taught us that the disease's biology is a critical factor determining the tumor cells' response to any therapy and hence the final outcome of the disease. Here we propose two scenarios wherein apoptosis can be induced in ER+/HER2- breast cancers expressing wild type TP53 and RB genes following combinations of BCL2 inhibitor, MDM2 inhibitor, and cell-cycle inhibitor. The suggested combinations are contextual and based on the current understanding of the cell signaling in the ER+/HER2- breast cancers. The two combinations of drugs are (1) BCL2 inhibitor plus a cell-cycle inhibitor, which can prime the tumor cells for apoptosis, and (2) BCL2 inhibitor plus an MDM2 inhibitor.

Optimal Treatment Duration of Neoadjuvant Endocrine Therapy for Women Aged 60 Years or Older with Estrogen Receptor-Positive, HER2-Negative Invasive Breast Cancer

BACKGROUND

Neoadjuvant endocrine therapy is not the standard of care for breast cancer, primarily because the optimal treatment duration remains unclear. This phase 2 prospective multicenter study analyzed time to progression, time to maximal response, and time to treatment failure for neoadjuvant exemestane.

METHODS

Inclusion criteria were women aged ≥60 years with Stage II or III breast cancer classified as estrogen receptor-positive/human epidermal growth factor receptor 2-negative. Response was defined as a ≥10% and minimum of 3 mm decrease in tumor size, as compared with the most recent or smallest value, and no new lesion. Progression was defined as a >10% and minimum of over 3 mm increase in tumor size, as compared with the most recent or smallest value, or a new lesion. Maximal response was defined as the final recorded response.

RESULTS

This study included 24 women, most of whom had T2 N0 tumors with high estrogen receptor expression. We initially observed a response in 23 patients (96%); however, 6 patients (25%) later experienced progression. Time to progression, time to maximal response, and time to treatment failure ranged from 7 to 22 months (estimated median, 35), 1 to 22 months (estimated median, 10), and 2 to 22 months (estimated median, 22), respectively. Treatment duration varied widely, but the estimated optimal duration of neoadjuvant exemestane therapy was 22 to 35 months in patients seeking to avoid surgery and 10 months in patients wishing to receive breast-conserving surgery.

CONCLUSIONS

Neoadjuvant exemestane therapy is long effective for older women with hormone-sensitive breast cancer.

Neoadjuvant endocrine therapy in locally advanced estrogen or progesterone receptor-positive breast cancer: determining the optimal endocrine agent and treatment duration in postmenopausal women-a literature review and proposed guidelines

Introduction

For patients with locally advanced estrogen receptor or progesterone receptor-positive breast cancer, neoadjuvant endocrine therapy (NET) facilitates down-staging of the tumor and increased rates of breast-conserving surgery. However, NET remains under-utilized, and there are very limited clinical guidelines governing which therapeutic agent to use, or the optimal duration of treatment in postmenopausal women. This literature review aims to discuss the evidence surrounding (1) biomarkers for patient selection for NET, (2) the optimal neoadjuvant endocrine agent for postmenopausal women with locally advanced breast cancer, and (3) the optimal duration of NET. In addition, we make initial recommendations towards developing a clinical guideline for the prescribing of NET.

Method

A wide-ranging search of online electronic databases was conducted using a truncated PIC search strategy to identify articles that were relevant to these aims and revealed a number of key findings.

Results

Randomized trials have consistently demonstrated that aromatase inhibitors are more effective than tamoxifen, in terms of objective response rate and rate of BCS, and should be used as first-line NET. The three available aromatase inhibitors have so far been demonstrated to be biologically equivalent, with the choice of aromatase inhibitor not having been shown to affect clinical outcomes. There is increasing evidence for extending the duration of NET beyond 3 to 4 months, to at least 6 months or until maximal clinical response is achieved. While on-treatment levels of the proliferation marker Ki67 are predictive of long-term outcome, the choice of adjuvant therapy in patients who have received NET and then surgery is best guided by the preoperative endocrine prognostic index, or PEPI, which incorporates Ki67 with other clinical parameters.

Conclusion

This study reveals that in appropriately selected patients, NET can provide equivalent clinical benefit to neoadjuvant chemotherapy in the same cohort, if suitable treatments and durations are chosen. Our findings highlight the need for better defined biomarkers both for guiding patient selection and for measuring outcomes. Development of standard guidelines for the prescribing of NET has the potential to improve both clinical outcomes and quality of life in this patient cohort.

Efficacy of neoadjuvant endocrine therapy compared with neoadjuvant chemotherapy in pre-menopausal patients with oestrogen receptor-positive and HER2-negative, lymph node-positive breast cancer

Introduction

Neoadjuvant endocrine therapy (NET) has demonstrated efficacy in post-menopausal patients with hormone-responsive breast cancer. This trial was designed to compare the efficacy of neoadjuvant chemotherapy (NCT) with NET in pre-menopausal breast cancer.

Patients and methods

In this prospective, randomised, phase III study, oestrogen receptor (ER)-positive, HER2-negative, and lymph node-positive pre-menopausal breast cancer patients were recruited from 7 hospitals in South Korea. Enrolled patients were randomly assigned (1:1) to receive 24 weeks of either NCT or NET with goserelin and tamoxifen. The primary purpose was to evaluate the non-inferiority of NET compared to NCT using clinical response, assessed by MRI. Besides, pathological complete response rate (pCR), changes in Ki-67 expression, breast conservation surgery (BCS) rate, and quality of life were included as secondary endpoints.

Results

A total of 187 patients were assigned to receive NCT (n = 95) or NET (n = 92), and 87 patients in each group completed treatments. More NCT patients had complete response or partial response than NET patients using MRI (NCT 83.7% vs. NET 52.9%, 95% CI 17.6–44.0, p < 0.001) and callipers (NCT 83.9% vs. NET 71.3%, 95% CI 0.4–24.9, p = 0.046). Three NCT patients (3.4%) and one NET patient (1.2%) showed pCR (p < 0.005). No difference existed in the conversion rate of BCS (13.8% for NCT vs. 11.5% for NET, p = 0.531) and Ki-67 change (p = 0.114) between the two groups. Nineteen NCT patients had treatment-related grade 3 or worse events compared with none in the NET group.

Conclusions

Better clinical responses were observed in pre-menopausal patients after 24 weeks of NCT compared to those observed after NET.

Trial registration

Clinicaltrials.gov, NCT01622361. Registration June 19, 2012.

Aberrant Regulation of RAD51 Promotes Resistance of Neoadjuvant Endocrine Therapy in ER-positive Breast Cancer

Breast cancer is one of the most common malignant cancers affecting females. Estrogen receptor (ER)-positive breast cancer is responsive to endocrine therapy. Although current therapies offer favorable prospects for improving survival, the development of resistance remains a severe problem. In this study, we explored the resistance mechanisms of ER-positive breast cancer to neoadjuvant endocrine therapy. Microarray data of GSE87411 contained 109 pairs of samples from Z1031 trial, including untreated samples and post-treated samples with neoadjuvant aromatase inhibitor (AI) therapy. The differentially expressed genes (DEGs) were obtained from two different comparisons: untreated samples versus post-treated samples with AIs, and post-treated samples sensitive versus resistant to AIs. Multiple bioinformatic methods were applied to evaluate biological function, protein-protein network and potential binding between target protein and aromatase inhibitor. Then, regulation of gene expression, DNA methylation and clinicopathological factors of breast cancer were further analyzed with TCGA data. From GSE87411 dataset, 30 overlapped DEGs were identified. Cell division was found to be the main function of overlapped DEGs by functional enrichment and gene ontology (GO) analysis. RAD51 recombinase (RAD51), a key protein of homologous recombination, was detected to interact with BReast CAncer genes 2 (BRCA2). Moreover, according to the docking simulation, RAD51 might potentially bind to AIs. Overexpressed RAD51 was associated with hypermethylation of BRCA2, resistance to AIs and poor overall survival of patients with ER-positive breast cancer. Furthermore, RAD51 was found to be a better indicator than MKI67 for predicting resistance in neoadjuvant setting. The results indicated that methylation of BRCA2 led to incomplete suppression on RAD51, which caused an increased expression of RAD51, subsequently AI-resistance and poor prognosis in ER-positive breast cancer. RAD51 could be a new candidate used as a predicative marker and therapeutic target in neoadjuvant endocrine treatment.

A Phase II Randomized Study of Neoadjuvant Letrozole Plus Alpelisib for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer (NEO-ORB)

PURPOSE

Addition of alpelisib to fulvestrant significantly extended progression-free survival in PIK3CA-mutant, hormone receptor-positive (HR+) advanced/metastatic breast cancer in the phase III SOLAR-1 study. The combination of alpelisib and letrozole also had promising activity in phase I studies of HR+ advanced/metastatic breast cancer. NEO-ORB aimed to determine whether addition of alpelisib to letrozole could increase response rates in the neoadjuvant setting.Patients and Methods: Postmenopausal women with HR+, human epidermal growth factor receptor 2-negative, T1c-T3 breast cancer were assigned to the PIK3CA-wild-type or PIK3CA-mutant cohort according to their tumor PIK3CA status, and randomized (1:1) to 2.5 mg/day letrozole with 300 mg/day alpelisib or placebo for 24 weeks. Primary endpoints were objective response rate (ORR) and pathologic complete response (pCR) rate for both PIK3CA cohorts.

RESULTS

In total, 257 patients were assigned to letrozole plus alpelisib (131 patients) or placebo (126 patients). Grade ≥3 adverse events (≥5% of patients) in the alpelisib arm were hyperglycemia (27%), rash (12%), and maculo-papular rash (8%). The primary objective was not met; ORR in the alpelisib versus placebo arm was 43% versus 45% and 63% versus 61% in the PIK3CA-mutant and wild-type cohorts, respectively. pCR rates were low in all groups. Decreases in Ki-67 were similar across treatment arms and cohorts. In PIK3CA-mutant tumors, alpelisib plus letrozole treatment induced a greater decrease in phosphorylated AKT versus placebo plus letrozole.

CONCLUSIONS

In contrast to initial results in advanced/metastatic disease, addition of alpelisib to 24-week neoadjuvant letrozole treatment did not improve response in patients with HR+ early breast cancer.

Neoadjuvant Therapy for Breast Cancer as a Model for Translational Research

Neoadjuvant therapy, where patients receive systemic therapy before surgical removal of the tumour, can downstage tumours allowing breast-conserving surgery, rather than mastectomy. In addition to its impact on surgery, the neoadjuvant setting offers a valuable opportunity to monitor individual tumour response. The effectiveness of standard and/or potential new therapies can be tested in the neoadjuvant pre-surgical setting. It can potentially help to identify markers differentiating patients that will potentially benefit from continuing with the same or a different adjuvant treatment enabling personalised treatment. Characterising the molecular response to treatment over time can more accurately identify the significant differences between baseline samples that would not be identified without post-treatment samples. In this review, we discuss the potential and challenges of using the neoadjuvant setting in translational breast cancer research, considering the implications for improving our understanding of response to treatment, predicting therapy benefit, modelling breast cancer dormancy, and the development of drug resistance.

Validation of the 21-gene test as a predictor of clinical response to neoadjuvant hormonal therapy for ER+, HER2-negative breast cancer: the TransNEOS study

Purpose

The Recurrence Score test is validated to predict benefit of adjuvant chemotherapy. TransNEOS, a translational study of New Primary Endocrine-therapy Origination Study (NEOS), evaluated whether Recurrence Score results can predict clinical response to neoadjuvant letrozole.

Methods

NEOS is a phase 3 clinical trial of hormonal therapy ± adjuvant chemotherapy for postmenopausal patients with ER+, HER2-negative, clinically node-negative breast cancer, after six months of neoadjuvant letrozole and breast surgery. TransNEOS patients had tumors ≥ 2 cm and archived core-biopsy samples taken before neoadjuvant letrozole and subsequently sent for Recurrence Score testing. The primary endpoint was to evaluate clinical (complete or partial) response to neoadjuvant letrozole for RS < 18 versus RS ≥ 31. Secondary endpoints included evaluation of clinical response and rate of breast-conserving surgery (BCS) by continuous Recurrence Score result, ESR1 and PGR single-gene scores, and ER gene-group score.

Results

Of 295 TransNEOS patients (median age 63 years; median tumor size 25 mm; 66% grade 1), 53.2% had RS < 18, 28.5% had RS18–30, and 18.3% had RS ≥ 31. Clinical response rates were 54% (RS < 18), 42% (RS18–30), and 22% (RS ≥ 31). A higher proportion of patients with RS < 18 had clinical responses (p < 0.001 vs. RS ≥ 31). In multivariable analyses, continuous Recurrence Score result (p < 0.001), ESR1 score (p = 0.049), PGR score (p < 0.001), and ER gene-group score (p < 0.001) were associated with clinical response. Recurrence Score group was significantly associated with rate of BCS after neoadjuvant treatment (RS < 18 vs. RS ≥ 31, p = 0.010).

Conclusion

The Recurrence Score test is validated to predict clinical response to neoadjuvant letrozole in postmenopausal patients with ER+, HER2-negative, clinically node-negative breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4964-y) contains supplementary material, which is available to authorized users.

ER+ Breast Cancers Resistant to Prolonged Neoadjuvant Letrozole Exhibit an E2F4 Transcriptional Program Sensitive to CDK4/6 Inhibitors

Purpose: This study aimed to identify biomarkers of resistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancers treated with prolonged neoadjuvant letrozole.Experimental Design: We performed targeted DNA and RNA sequencing in 68 ER+ breast cancers from patients treated with preoperative letrozole (median, 7 months).Results: Twenty-four tumors (35%) exhibited a PEPI score ≥4 and/or recurred after a median of 58 months and were considered endocrine resistant. Integration of the 47 most upregulated genes (log FC > 1, FDR < 0.03) in letrozole-resistant tumors with transcription-binding data showed significant overlap with 20 E2F4-regulated genes (P = 2.56E-15). In patients treated with the CDK4/6 inhibitor palbociclib before surgery, treatment significantly decreased expression of 24 of the 47 most upregulated genes in letrozole-resistant tumors, including 18 of the 20 E2F4 target genes. In long-term estrogen-deprived ER+ breast cancer cells, palbociclib also downregulated all 20 E2F4 target genes and P-RB levels, whereas the ER downregulator fulvestrant or paclitaxel only partially suppressed expression of this set of genes and had no effect on P-RB. Finally, an E2F4 activation signature was strongly associated with resistance to aromatase inhibitors in the ACOSOG Z1031B neoadjuvant trial and with an increased risk of relapse in adjuvant-treated ER+ tumors in METABRIC.Conclusions: In tumors resistant to prolonged neoadjuvant letrozole, we identified a gene expression signature of E2F4 target activation. CDK4/6 inhibition suppressed E2F4 target gene expression in estrogen-deprived ER+ breast cancer cells and in patients' ER+ tumors, suggesting a potential benefit of adjuvant CDK4/6 inhibitors in patients with ER+ breast cancer who fail to respond to preoperative estrogen deprivation. Clin Cancer Res; 24(11); 2517-29. ©2018 AACR.

Current Status of Neoadjuvant Endocrine Therapy in Early Stage Breast Cancer

OPINION STATEMENT

Neoadjuvant endocrine therapy (NET) with Ki67-based response monitoring is a practical, cost-effective approach to the management of clinical stage II and III estrogen receptor-positive (ER+) breast cancer. In addition to marked improvements in rates of breast conservation, the identification of extreme responders on the basis of the preoperative endocrine prognostic index (PEPI) provides a rationale to avoid chemotherapy on the basis of highly favorable prognosis in some patients. Finally, samples accrued from patients treated with neoadjuvant therapy are providing valuable insights into the molecular basis for intrinsic resistance to endocrine therapy and promise a more rational basis and precise approach to the systemic treatment of ER+ breast cancer.

Randomized phase II study of anastrozole plus tegafur-uracil as neoadjuvant therapy for ER-positive breast cancer in postmenopausal Japanese women (Neo-ACET BC)

Purpose

This phase II study evaluated the efficacy and safety of anastrozole concurrent with tegafur/uracil (UFT) as neoadjuvant therapy for ER-positive postmenopausal breast cancer.

Methods

Postmenopausal Japanese women with ER-positive, HER2-negative, T2,N0-1,M0 breast cancer seen at tertiary hospitals were eligible for this open-label, randomized, multicenter study. Patients were randomized 1:1 by minimization to orally receive either anastrozole (1 mg once daily) plus UFT (tegafur/uracil combination in 1:4 molar ratio; 270 mg/m²/day in two divided doses) or anastrozole (as above) alone for 24 weeks. Tumor response was assessed by investigator and central review as per RECIST v1.1. The primary endpoint was the proportion of patients with best overall response of CR or PR [clinical response rate (RR)] determined by central radiologic review.

Results

The study was prematurely terminated due to Grade ≥ 3 liver dysfunction reported in 3 patients receiving anastrozole/UFT. Of 57 patients randomized before termination (29 anastrozole/UFT, 28 anastrozole), all were analyzed for safety and 56 (28 each group) for tumor response. Compared with anastrozole alone, anastrozole/UFT did not achieve significantly higher RR [39.3% (90% CI 23.8–56.5%) vs 14.3% (90% CI 5.0–29.8%); p = 0.0683, Fisher’s exact test], but produced significantly greater tumor shrinkage (mean tumor reduction rate 31.0 vs. 14.2%; p = 0.0181, unpaired t-test). Grade ≥ 3 adverse events were more common with anastrozole/UFT than with anastrozole (17.2 vs. 0%).

Conclusion

Although the study was terminated owing to the altered liver function, it showed that there was a trend to greater shrinkage of tumor in the combination group for ER-positive, HER2-negative postmenopausal breast cancer.

Impact of clinical response to neoadjuvant endocrine therapy on patient outcomes: a follow-up study of JFMC34-0601 multicentre prospective neoadjuvant endocrine trial

Background

Neoadjuvant endocrine therapy (NET) has been demonstrated to improve breast-conserving rate and is a widely accepted treatment option for postmenopausal patients with hormone receptor-positive breast cancer. There are few reports on the association of NET response and long-term outcomes.

Objectives

To investigate the prognostic value of clinical response to NET.

Methods

Long-term outcomes of NET were examined in 107 patients who participated in the multicentre prospective neoadjuvant exemestane study, JFMC34-0601. Patients were treated with 25 mg/day exemestane for 16 weeks followed by an 8-week extension depending on the treatment response.

Results

Clinical response included partial response (PR) in 58 patients, stable disease in 41 patients and progressive disease (PD) in 8 patients. Clinical response was significantly associated with disease-free survival (DFS), distant disease-free survival (DDFS) and overall survival (OS) (P<0.0001 for all). Especially, patients with PD showed markedly poor outcomes with median DFS=17.8 months (HR (vs PR): 7.7 (95% CI 1.6 to 33)) and median OS=37.7 months (HR (vs PR): 26.3 (95% CI 2.4 to 655)). Preoperative endocrine prognostic index (PEPI) were associated with DFS and marginally with OS (P=0.022 and 0.066, respectively). PEPI=0 indicated an excellent prognosis with 95% 5-year DFS (95% CI 73 to 99). In the multivariate analysis including T stage, nodal status and Ki67, clinical response was an independent prognostic factor for DFS, DDFS and OS (P=0.032, 0.0007 and 0.020, respectively), whereas PEPI was marginally associated with DFS and OS (P=0.079 and 0.068, respectively).

Conclusions

Clinical response to NET showed an independent prognostic value. Patients with PD had markedly poor prognosis, indicating a need of additional therapy. PEPI=0 indicated an excellent prognosis. The integration of clinical response and PEPI would improve decision-making with regard to treatment options for endocrine-responsive breast cancer when these results are validated in a larger clinical trial.

Trial registration number

UMIN C000000345.

Trends in progression-free survival (PFS) and time to progression (TTP) over time within first-line aromatase inhibitors trials in hormone receptor-positive advanced breast cancer

BACKGROUND

Over the last 20 years, aromatase inhibitors (AI) have been tested in clinical trials as first-line therapy for hormone receptor-positive (HR-positive) advanced breast cancer (ABC), firstly as experimental arms, when they proved to be effective, and recently as control arms. This analysis aims to evaluate trends in progression-free survival (PFS) and time to progression (TTP) over time.

PATIENTS AND METHODS

A literature review was conducted using the MEDLINE database to identify randomized controlled phase II or III trials which reported PFS or TTP of at least one arm using first-line AI HR-positive ABC patients. A linear correlation was used to access the association between the year of the first patient enrolled and the observed PFS/TTP.

RESULTS

The search retrieved 19 trials, accounting for 4552 postmenopausal patients divided into 21 separate AI treatment arms. The PFS/TTP increased from 6 to 9 months in the earlier trials to 13-16 months in the current era, representing an absolute gain of approximately 7 months, without the addition of any other drug. Our analysis showed a positive correlation between the year of the first patient enrolled in these trials and median PFS/TTP reported (R ² = 0.34; p < 0.01). No correlation was found between the year of the first patient included in these trials and other potential prognostic factors such as visceral metastasis at baseline (R ² = 0.26; p = 0.20) or exposure to adjuvant therapy (R ² = 0.05; p = 0.18).

CONCLUSION

Patients treated with first-line AIs in the more recently conducted trials have longer PFS/TTP when compared to their counterparts treated with the same drugs in older studies. These findings have important implications for the estimation of sample size and follow-up periods for the planning of future trials as well as in the translation of the results into clinical practice decisions.

Neoadjuvant Endocrine Therapy: Who Benefits Most?

Neoadjuvant endocrine therapy (NET) can be effective at downstaging patients with estrogen receptor-positive tumors and identifying those tumors that are endocrine sensitive and resistant. The optimal prognostic markers for stratification are under investigation. Use of NET will allow the identification of patients with estrogen receptor-positive tumors who might benefit from additional treatment and allow better understanding of endocrine resistance.

Neoadjuvant endocrine therapy in breast cancer patients

HIGHLIGHTS

The overall response rate to neoadjuvant endocrine therapy (NET) was 54.55%.The eight patients proposed to tumour's downstage, after 9.71 months of NET, preserved their breast.In the group which achieved response, 10.28 months was the mean time to accomplish it.Even patients who had the worst outcome only began to suffer latter in the course of therapy.NET can be done beyond the conventional 3-4 months to allow additional downstage of the tumour.

BACKGROUND

The aim of this study is to evaluate if the extension of neoadjuvant endocrine therapy (NET), beyond the conventional time, allows additional downstage of the tumour, in order to perform a breast conservative surgery (BCS), and to analyze if it is a good option for long-term control in patients who refuse or are unfit for surgery.

PATIENTS AND METHODS

We retrospectively reviewed a database containing all patients treated in our institution with NET. All included patients were post-menopausal with primary local disease. The type of response obtained was assessed using modified RECIST criteria.

RESULTS

Thirty-three patients were included. Two patients had tumours with 90% expression of oestrogen receptors and all the others had 100%. The tumour size in the largest diameter was 6.51 cm before treatment and 5.18 cm after. Eighteen patients achieved a partial response after 10.28 months of therapy. Patients that were proposed to downstage the tumour performed 9.71 months of therapy until surgery and all were submitted to BCS. Progression occurred after 27.5 months.

CONCLUSION

Endocrine therapy is a feasible option for a longer time to allow additional downstage of the tumour and is a good solution in patients who refuse or are unfit for surgery.

Age-related Disparity: Breast Cancer in the Elderly

Aging poses an unique opportunity to study cancer biology and treatment in older adults. Breast cancer is often studied in young women; however, much investigation remains to be done on breast cancer in our expanding elderly population. Diagnostic and management strategies applicable to younger patients cannot be empirically used to manage older breast cancer patients. Lack of evidence-based data continues to be the major impediment toward delivery of personalized cancer care to elderly breast cancer patients. This article reviews the relevant literature on management of curable breast cancer in the elderly, the role of geriatric assessment, complex treatment decision making within the context of patient's expected life expectancy, comorbidities, physical function, socioeconomic status, barriers to health care delivery, goals of treatment, and therapy-related side effects. Continuing efforts for enrolling elderly breast cancer patients in contemporary clinical trials, and thus improving age-appropriate care, are emphasized.

Neoadjuvant Trials in ER+ Breast Cancer: A Tool for Acceleration of Drug Development and Discovery

Neoadjuvant therapy trials offer an excellent strategy for drug development and discovery in breast cancer, particularly in triple-negative and HER2-overexpressing subtypes, where pathologic complete response is a good surrogate of long-term patient benefit. For estrogen receptor-positive (ER+) breast cancers, however, use of this strategy has been challenging because of the lack of validated surrogates of long-term efficacy and the overall good prognosis of the majority of patients with this cancer subtype. We review below the clinical benefits of neoadjuvant endocrine therapy for ER+/HER2-negative breast cancer, its use and limitations for drug development, prioritization of adjuvant and metastatic trials, and biomarker discovery.Significance: Neoadjuvant endocrine therapy is an excellent platform for the development of investigational drugs, triaging of novel combinations, biomarker validation, and discovery of mechanisms of drug resistance. This review summarizes the clinical and investigational benefits of this approach, with a focus on how to best integrate predictive biomarkers into novel clinical trial designs. Cancer Discov; 7(6); 561-74. ©2017 AACR.

Short-term outcomes of neoadjuvant hormonal therapy versus neoadjuvant chemotherapy in breast cancer: systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Estrogen receptor positive (ER⁺) breast cancer (BC) is highly hormonal therapy-responsive. The choice between neoadjuvant hormonal therapy (NHT) and neoadjuvant chemotherapy (NCT) remains controversial. The aim of this meta-analysis was to evaluate benefits and safety of NHT compared with NCT for operable BC patients. Areas covered: Electronic databases were searched to identify randomized clinical trials (RCTs) comparing NHT and NCT for treatment of invasive and immunohistochemically ER⁺ BC. Major outcomes were clinical response rate, pathologic complete response (pCR), operation methods, recurrence, and adverse events. Five RCTs were included. The clinical response rates between NHT and NCT were not statistically different overall, or in ER-rich patients or postmenopausal women. Compared with NCT, NHT had a significant reduction of complete response rate and an increment in progressive disease rate. NHT increased rates of breast conserving surgery (BCS) and wide local excision (WLE) compared with NCT. All the other parameters were comparable. Patients receiving NHT had better tolerance than those undergoing NCT. Expert commentary: When treating BC, NHT was well tolerated, and contributed to more BCS and WLE cases, especially in ER-rich postmenopausal patients. While for those who are eligible for chemotherapy, NCT might be better recommended due to higher response rates.

Neoadjuvant Endocrine Therapy for Estrogen Receptor-Positive Breast Cancer: A Systematic Review and Meta-analysis

Importance

Estrogen receptor-positive (ER+) tumors of the breast are generally highly responsive to endocrine treatment. Although endocrine therapy is the mainstay of adjuvant treatment for ER+ breast cancer, the role of endocrine therapy in the neoadjuvant setting is unclear.

Objective

To evaluate the effect of neoadjuvant endocrine therapy (NET) on the response rate and the rate of breast conservation surgery (BCS) for ER+ breast cancer.

Data Sources

Based on PRISMA guidelines, a librarian-led search of PubMed and Ovid MEDLINE was performed to identify eligible trials published from inception to May 15, 2015. The search was performed in May 2015.

Study Selection

Inclusion criteria were prospective, randomized, neoadjuvant clinical trials that reported response rates with at least 1 arm incorporating NET (n = 20). Two authors independently analyzed the studies for inclusion.

Data Extraction and Synthesis

Pooled odds ratios (ORs), 95% CIs, and P values were estimated for end points using the fixed- and random-effects statistical model.

Results

The analysis included 20 studies with 3490 unique patients. Compared with combination chemotherapy, NET as monotherapy with aromatase inhibitors had a similar clinical response rate (OR, 1.08; 95% CI, 0.50-2.35; P = .85; n = 378), radiological response rate (OR, 1.38; 95% CI, 0.92-2.07; P = .12; n = 378), and BCS rate (OR, 0.65; 95% CI, 0.41-1.03; P = .07; n = 334) but with lower toxicity. Aromatase inhibitors were associated with a significantly higher clinical response rate (OR, 1.69; 95% CI, 1.36-2.10; P < .001; n = 1352), radiological response rate (OR, 1.49; 95% CI, 1.18-1.89; P < .001; n = 1418), and BCS rate (OR, 1.62; 95% CI, 1.24-2.12; P < .001; n = 918) compared with tamoxifen. Dual combination therapy with growth factor pathway inhibitors was associated with a higher radiological response rate (OR, 1.59; 95% CI, 1.04-2.43; P = .03; n = 355), but not clinical response rate (OR, 0.76; 95% CI, 0.54-1.07; P = .11; n = 537), compared with endocrine monotherapy. The incidence of pathologic complete response was low (<10%).

Conclusions and Relevance

Neoadjuvant endocrine therapy, even as monotherapy, is associated with similar response rates as neoadjuvant combination chemotherapy but with significantly lower toxicity, suggesting that NET needs to be reconsidered as a potential option in the appropriate setting. Additional research is needed to develop rational NET combinations and predictive biomarkers to personalize the optimal neoadjuvant strategy for ER+ breast cancer.

Implementing neoadjuvant endocrine strategies in ER-positive, HER2-negative breast cancer

INTRODUCTION

Although neoadjuvant chemotherapy has been widely adopted as it increases breast conservation rates, permits the in vivo testing of the activity of chemotherapeutics and offers the opportunity to conduct translational research based on longitudinal assessments of tumor tissue, neoadjuvant endocrine therapy has been met with skepticism owing to slow regression rates and a low chance for pathologic remission. Areas covered: Herein, the results of clinical trials comparing different endocrine agents as neoadjuvant treatment, endocrine therapy with chemotherapy, treatment duration, novel combinations and putative biomarkers are reviewed, with the aim to better understand the current and future role of this modality in clinical practice. Expert commentary: Available evidence clearly indicates that, in properly selected patients, short-term outcomes do not differ compared to chemotherapy. In addition, the realization that its effects at the cellular level occur shortly after its initiation and have important prognostic implications, could serve as a tool for the early identification of non-responders. Ongoing trials which integrate novel agents in addition to endocrine therapies will help guide treatment decisions and may establish neoadjuvant endocrine therapy as a standard of care for well-defined patient subgroups.

[Systemic neoadjuvant therapy of luminal breast cancer in 2016]

Neoadjuvant systemic therapies have been extensively evaluated in luminal breast cancer. Conventional cytotoxic chemotherapy increases breast conservation rate, albeit with a low level of complete pathological response of uncertain clinical significance. Endocrine therapies allow similar clinical results with much less side effects. Biological criteria of response to endocrine therapies are still being defined. The neoadjuvant setting must be used for early development of new compounds and to further document biological mechanisms of sensitivity and resistance to treatments.

Neoadjuvant endocrine therapy in breast cancer: current role and future perspectives

Luminal breast cancer, as defined by oestrogen and/or progesterone expression by immunohistochemistry, accounts for up to 75% of all breast cancers. In this population, endocrine therapy is likely to account for most of the gains obtained with the administration of adjuvant systemic treatment. The role of adjuvant chemotherapy in these patients remains debatable since it is known that only a small fraction of patients will derive meaningful benefit from this treatment whilst the majority will be exposed to significant and unnecessary chemotherapy-related toxicities, in particular the elderly and frail. Therefore, neoadjuvant endocrine therapy (NET) becomes an attractive option for selected patients with hormonal-receptor positive locally advanced breast cancer. In this review, we discuss the current role of NET and future perspectives in the field.

Neoadjuvant endocrine treatment in early breast cancer: An overlooked alternative?

During the last decade neoadjuvant endocrine therapy (NET) has moved from being reserved for elderly and frail non-chemotherapy candidates to a primary systemic modality in selected patients with hormone sensitive breast cancer. Neoadjuvant hormonal treatment in patients with hormone receptor positive, HER-2 negative early breast cancer is proven to be an effective and safe option; it is associated with a higher rate of breast conserving surgery (BCS), may reduce the need for adjuvant chemotherapy and enables a delay of surgery for medical or practical reasons. Clinical responses range from 13% to 100% with at least 3 months of NET. Methods of assessing response should include MRI of the breast, particularly in lobular tumours. In studies comparing tamoxifen with aromatase inhibitors (AI), AI proved to be superior in terms of tumour response and rates of BCS. Change in Ki67 is accepted as a validated endpoint for comparing endocrine neoadjuvant agents. Levels of Ki67 during treatment are more closely related to long-term prognosis than pretreatment Ki67. Neoadjuvant endocrine therapy provides a unique opportunity for studies of endocrine responsiveness and the development of new experimental drugs combined with systemic hormonal treatment.

Neoadjuvant endocrine therapy: Patient selection, treatment duration and surrogate endpoints

Neoadjuvant endocrine treatment has become of increasing interest for downstaging primary ER+ breast cancers as it has become clear that the pathologic complete response rate of luminal tumours to chemotherapy is much lower than that of non-luminal and differs little from that to endocrine therapy. There is much more experience in postmenopausal than premenopausal women. Aromatase inhibitors are generally the agent of choice. Responses are lower in those with the low levels of ER. While duration of endocrine treatment in clinical trials has usually been standardized at around three to four months it is clear that volume reductions continue to occur beyond that time in a large proportion of cases and routine clinical practice is often to treat to maximum response. This relatively slow emergence of downstaging relates to the absence of any increase in apoptosis with endocrine therapy and dependence of responses on the antiproliferative effects of oestrogen withdrawal: apoptosis occurs but at a slightly lower rate such that cell loss is attritional. The dependence of responses on the reduced proliferation underpins the value of Ki67 as an intermediate end-point for treatment benefit with multiple studies having found that relative effects on proliferation by different drugs in neoadjuvant trials match their relative impact on recurrence. While change in Ki67 is now accepted as a validated endpoint for comparing endocrine agents in the neoadjuvant scenario, on-treatment levels of Ki67 are related to long-term prognosis more closely than pretreatment Ki67. The Preoperative Endocrine Prognostic Index (PEPI) that combines residual Ki67 score with measures of on-treatment ER and other clinicopathologic factors has also found application in clinical trials. The potential to make longitudinal assessments of both clinical and biomarker responses has encouraged the development of novel clinical trial designs for assessing the impact of agents that aim to enhance response beyond that of endocrine agents alone. Such strategies include the early measurement of residual Ki67 levels after challenge with an endocrine agent alone and evaluation of the impact of the added agent on Ki67 or other agent-specific end-points.

Efficacy of six month neoadjuvant endocrine therapy in postmenopausal, hormone receptor-positive breast cancer patients--a phase II trial

BACKGROUND

Neoadjuvant hormonal therapy (NHT) is playing an increasing role in the clinical management of breast cancer (BC) and may improve surgical outcomes for postmenopausal, oestrogen receptor (ER)-positive BC patients. However, there is currently no consensus on the optimal duration of NHT before surgery. Here, we present the outcomes of the TEAM IIA trial, a multicentre, phase II trial investigating the efficacy of six months of neoadjuvant exemestane in postmenopausal, strong ER-positive (ER+, ⩾50%) BC patients.

METHODS

102 patients (stage T2-T4ac) were included in the study after exclusion of ineligible patients. Primary end-point was clinical response at 3 and 6 months as measured by palpation. Secondary end-point was radiological response as measured by magnetic resonance imaging (MRI), mammography and/or ultrasound. Linear mixed models (95% confidence interval (CI)) were used to compare changes in mean tumour size (in mm) between baseline, 3 and 6 months after the start of endocrine therapy. Conversion rates from mastectomy to breast conserving surgery (BCS) were evaluated.

RESULTS

Median age of all patients was 72 years (range 53-88). Overall response rate by clinical palpation was 64.5% in all patients with a final palpation measurement. Four patients had clinically progressive disease. 63 patients had both 3-month and >3-month palpation measurements. Overall response was 58.7% at 3 months and 68.3% at final palpation (>3 months). Mean tumour size by clinical palpation at T=0 was 39.1mm (95% CI 34.8-43.4mm), and decreased to 23.0mm (95% CI 18.7-27.2mm) and 16.7 mm (95% CI 12.6-20.8) at T=3 and T>3 months, respectively (p=0.001). Final radiological response rates at the end of treatment for MRI (n=37), ultrasound (n=77) and mammography (n=56) were 70.3%, 41.6% and 48.2%, respectively. Feasibility of BCS improved from 61.8% to 70.6% (McNemar p=0.012).

CONCLUSION

6 months of neoadjuvant exemestane therapy helps reduce mean tumour size further in strongly ER-positive BC patients without significant side-effects compared to 3 months. Nevertheless, some patients still experience disease progression under exemestane. Feasibility of breast conservation rates improved by almost 10%.

Predicting targeted drug combinations based on Pareto optimal patterns of coexpression network connectivity

Background

Molecularly targeted drugs promise a safer and more effective treatment modality than conventional chemotherapy for cancer patients. However, tumors are dynamic systems that readily adapt to these agents activating alternative survival pathways as they evolve resistant phenotypes. Combination therapies can overcome resistance but finding the optimal combinations efficiently presents a formidable challenge. Here we introduce a new paradigm for the design of combination therapy treatment strategies that exploits the tumor adaptive process to identify context-dependent essential genes as druggable targets.

Methods

We have developed a framework to mine high-throughput transcriptomic data, based on differential coexpression and Pareto optimization, to investigate drug-induced tumor adaptation. We use this approach to identify tumor-essential genes as druggable candidates. We apply our method to a set of ER⁺ breast tumor samples, collected before (n = 58) and after (n = 60) neoadjuvant treatment with the aromatase inhibitor letrozole, to prioritize genes as targets for combination therapy with letrozole treatment. We validate letrozole-induced tumor adaptation through coexpression and pathway analyses in an independent data set (n = 18).

Results

We find pervasive differential coexpression between the untreated and letrozole-treated tumor samples as evidence of letrozole-induced tumor adaptation. Based on patterns of coexpression, we identify ten genes as potential candidates for combination therapy with letrozole including EPCAM, a letrozole-induced essential gene and a target to which drugs have already been developed as cancer therapeutics. Through replication, we validate six letrozole-induced coexpression relationships and confirm the epithelial-to-mesenchymal transition as a process that is upregulated in the residual tumor samples following letrozole treatment.

Conclusions

To derive the greatest benefit from molecularly targeted drugs it is critical to design combination treatment strategies rationally. Incorporating knowledge of the tumor adaptation process into the design provides an opportunity to match targeted drugs to the evolving tumor phenotype and surmount resistance.

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.

Influence networks based on coexpression improve drug target discovery for the development of novel cancer therapeutics

Background

The demand for novel molecularly targeted drugs will continue to rise as we move forward toward the goal of personalizing cancer treatment to the molecular signature of individual tumors. However, the identification of targets and combinations of targets that can be safely and effectively modulated is one of the greatest challenges facing the drug discovery process. A promising approach is to use biological networks to prioritize targets based on their relative positions to one another, a property that affects their ability to maintain network integrity and propagate information-flow. Here, we introduce influence networks and demonstrate how they can be used to generate influence scores as a network-based metric to rank genes as potential drug targets.

Results

We use this approach to prioritize genes as drug target candidates in a set of ER ⁺ breast tumor samples collected during the course of neoadjuvant treatment with the aromatase inhibitor letrozole. We show that influential genes, those with high influence scores, tend to be essential and include a higher proportion of essential genes than those prioritized based on their position (i.e. hubs or bottlenecks) within the same network. Additionally, we show that influential genes represent novel biologically relevant drug targets for the treatment of ER ⁺ breast cancers. Moreover, we demonstrate that gene influence differs between untreated tumors and residual tumors that have adapted to drug treatment. In this way, influence scores capture the context-dependent functions of genes and present the opportunity to design combination treatment strategies that take advantage of the tumor adaptation process.

Conclusions

Influence networks efficiently find essential genes as promising drug targets and combinations of targets to inform the development of molecularly targeted drugs and their use.

Neoadjuvant endocrine treatment for breast cancer: from bedside to bench and back again?

In recent years, considerable attention has been paid to the role of neoadjuvant chemotherapy as a pluripotential test bed for the treatment of breast cancer. Although traditionally reserved to render inoperable disease operable, neoadjuvant chemotherapy is increasingly being used to improve the chance for breast-conserving surgery, to gain information on pathologic response rates for a more rapid assessment of new chemotherapy-biologic regimens, and also to study in vivo tumour sensitivity or resistance to the agent being used. Similarly, use of neoadjuvant endocrine treatment was also traditionally restricted to elderly or frail patients who were felt to be unsuitable for chemotherapy. It is therefore not surprising that, given the increasing realization of the pivotal role of endocrine therapy in patient care, there is enhanced interest in neoadjuvant endocrine therapy not only as a less-toxic alternative to chemotherapy, but also to assess tumour sensitivity or resistance to endocrine agents. The availability of newer endocrine manipulations and increasing evidence that the benefits of chemotherapy are frequently marginal in many hormone-positive patients is making endocrine therapy increasingly important in the clinical setting. The hope is that, one day, instead of preoperative endocrine therapy being restricted to the infirm and the elderly, it will be used in the time between biopsy diagnosis and surgery to predict which patients will or will not benefit from chemotherapy in the adjuvant setting.

Use of the neo-adjuvant exemestane in post-menopausal estrogen receptor-positive breast cancer: a randomized phase II trial (PTEX46) to investigate the optimal duration of preoperative endocrine therapy

PURPOSE

The optimal treatment duration time and the causal relationship between neoadjuvant endocrine therapy and clinical response are not clear. Therefore, we conducted the present study to investigate the potential benefits of neoadjuvant exemestane therapy with the goal of identifying the optimal treatment duration.

METHODS

This study was conducted at three hospitals, as a multicenter, randomized phase II trial(UMIN000005668) of pre-operative exemestane treatment in post-menopausal women with untreated primary breast cancer. Fifty-one post-menopausal women with ER-positive and/or PgR-positive invasive breast cancer were randomly assigned to exemestane for 4 months or 6 months. Clinical response, pathological response, and decisions regarding breast-conserving surgery were the main outcome measures.

RESULTS

Of the 52 patients that enrolled, 51 patients underwent surgery. Of those, 26 and 25 patients had been treated with exemestane for 4 and 6 months, respectively. Treatments were performed at 3 hospitals in Japan between April 2008 and August 2010. The response rates as assessed by clinical examination were 42.3% and 48.0% for 4 and 6 months of treatment, respectively. Pathological responses (minimal response or better) were observed in 19.2% and 32.0% of patients, and breast-conserving surgery was performed on 50.0% and 48.0% of patients from the 4 and 6 month treatment groups, respectively.

CONCLUSION

The results of this study demonstrate that responses were equal to 4 or 6 months of exemestane treatment. Therefore, we propose that the rates of breast-conserving surgery could be maximized by 4 months of treatment. Furthermore, in addition to using exemestane as a preoperative treatment in post-menopausal women with ER-positive breast cancer, we envision administering the drug over the long term under careful clinical supervision.

Neoadjuvant treatment of breast cancer

Neoadjuvant treatment of breast cancer has become established as the safe and often effective therapeutic approach of choice for larger primary and for locally advanced breast cancer. The neoadjuvant approach offers the advantages of downstaging the disease, potentially reducing the extent of surgery and in an era of individualization of therapy, testing the efficacy of therapy administered to patients. The preoperative setting is also an effective way to study the activity of novel agents or therapeutic combinations in vivo against human breast cancer. For new therapies, preoperative trials avoid the issue of adaptive resistance and pretreatments that can be problematic in the advanced disease setting. For evidence of a drug targeting the cancer in vivo, comparisons of endocrine therapy, chemotherapy agents and/or targeted agents can provide data on activity and efficacy with a much shorter time frame and many fewer patients than for adjuvant trials; effects seen in neoadjuvant trials may even reflect what is found in the adjuvant setting. Patient benefits from the neoadjuvant approach may be greatest for those who experience complete pathologically documented response (and the consequent survival benefits) and women for whom breast conservation, rather than mastectomy, becomes possible.

Letrozole in the neoadjuvant setting: the P024 trial

Neoadjuvant chemotherapy trials have consistently reported lower response rates in hormone receptor-positive (HR+) breast cancer when compared with HR- cases. Preoperative endocrine therapy has therefore become a logical alternative and has gained considerable momentum from the finding that aromatase inhibitors (AIs) are more effective than tamoxifen for HR+ breast cancer in both the neoadjuvant and adjuvant settings. The most convincing neoadjuvant trial to demonstrate the superiority of an AI versus tamoxifen was the P024 study, a large multinational double-blind trial in postmenopausal women with HR+ breast cancer ineligible for breast-conserving surgery. The overall response rate (ORR) was 55% for letrozole and 36% for tamoxifen (P<0.001). Significantly more letrozole-treated patients underwent breast-conserving surgery (45 vs. 35%, respectively; P=0.022). In addition, ORR was significantly higher with letrozole than tamoxifen in the human epidermal growth factor receptor HER1/HER2+ subgroup (P=0.0004). The clinical efficacy of letrozole in HER2+ breast cancer was confirmed by fluorescent in situ hybridization analysis and was found to be comparable to that of HER2- cases (ORR 71% in both subsets). Biomarker studies confirmed the superiority of letrozole in centrally assessed estrogen receptor-positive (ER+) tumors and found a strong relationship with the degree of ER positivity for both agents. Interestingly, letrozole was effective even in marginally ER+ tumors and, unlike tamoxifen, consistently reduced the expression from estrogen-regulated genes (progesterone receptor and trefoil factor 1). Furthermore, when analyzed by Ki67 immunohistochemistry, letrozole was significantly more effective than tamoxifen in reducing tumor proliferation (P=0.0009). Thus, neoadjuvant letrozole is safe and superior to tamoxifen in the treatment of postmenopausal women with HR+ locally advanced breast cancer.