Endocrine therapy and related issues in hormone receptor-positive early breast cancer: a roundtable discussion by the breast cancer therapy expert group (BCTEG)

Experiences and management needs of endocrine therapy-related symptoms in patients with breast cancer: a systematic review and qualitative evidence synthesis protocol

INTRODUCTION

Patients with breast cancer and endocrine therapy-related symptoms often experience pain, self-denial, anxiety, fear of recurrence and despair, which can be extremely physically and psychologically traumatising for the patients. Failure to receive effective support and management reduces adherence to medications, leading to a higher risk of relapse and mortality. Clearly, it is paramount to identify what support these patients may need and how to meet their symptom management needs. This paper outlines a protocol to synthesise qualitative evidence on endocrine therapy symptom experiences, management expectations and preferences of patients with breast cancer.

METHODS AND ANALYSIS

The following databases were searched in November 2023 with no date restriction applied: The Cochrane Library, PubMed, Embase, Web of Science, Scopus, CINAHL and OpenGrey. Published studies on qualitative or mixed-method on symptom experiences and management needs during endocrine therapy in patients with breast cancer will be retrieved. We will also search for reference lists and perform a forward citation search. Before inclusion in this review, two reviewers will independently apply the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Qualitative Research to ensure methodological validity. Any disagreements regarding the evaluation of the articles will be resolved through discussion with or by a third reviewer. Data will be extracted using the standardised data extraction tool EndNote20 for unified management, assessment, and review of information. The common sense model of self-regulation will guide data extraction and synthesis. The final synthesised findings will be graded according to the GRADE-CERQual approach to establish confidence.

ETHICS AND DISSEMINATION

This systematic review addressed previously published studies without personally identifiable participant information. Ethical approval from the research committee was not required. The findings of this systematic review will be disseminated to various key stakeholders and published in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42023406987.

Impact of adjuvant endocrine therapy on prognosis in small hormone receptor-positive, HER2-negative early breast cancer

BACKGROUND

The efficacy of adjuvant endocrine therapy for hormone receptor-positive breast cancer has been previously established. However, significant adverse events related to endocrine therapy cannot be ignored. T1 breast cancer is expected to have a good prognosis. Therefore, adjuvant endocrine therapy for T1a breast cancer patients is controversial. Thus, in this study, we examined the effect of endocrine therapy on the prognosis of T1N0 hormone receptor-positive, HER2-negative breast cancer patients in each tumor size group, and re-considered the application of endocrine therapy.

METHODS

We retrospectively obtained clinical and pathological data from medical records of 7635 patients who underwent surgery for breast cancer at Aichi Cancer Hospital between January 2000 and December 2017. The primary end point of our analysis was disease-free survival (DFS). The secondary end points were distant disease-free survival (DDFS), overall survival (OS), and breast cancer-specific survival (BCSS). The log-rank test, cumulative survival generated curves with Kaplan-Meier methods and the hazard ratio (HR) calculated with a Cox regression model were used to assess the effects of endocrine therapy on prognosis.

RESULTS

The 5-year DFS was worse in the non-endocrine therapy (non-ET) group (78%) than the endocrine therapy (ET) group (95%) in the T1c population (p < 0.001, HR 0.25). However, there was no statistically significant difference in DFS between the ET and the non-ET groups in T1a (ET 96% vs non-ET 93%, p = 0.9314, HR 0.94) and T1b (ET 96% vs non-ET 93%, p = 0.1481HR 0.53) breast cancer. The OS, DDFS, and BCSS of the patients also showed that endocrine therapy was associated with improvement of the prognosis in the T1c group, but not in the T1a and T1b groups.

CONCLUSIONS

Adjuvant endocrine therapy may be essential for T1c breast cancer patients. In contrast, this therapy should be discussed for T1a and T1b luminal breast cancer patients under some circumstances, such as suffering from adverse events.

Advances in Therapeutic Approaches for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), defined as breast cancer lacking expression of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2), accounts for up to 20% of all breast cancer, and it occurs at a higher frequency in younger, African American, and Hispanic women. Compared to breast cancers that are hormone receptor and/or HER2 positive, TNBC has an aggressive clinical course and worse prognosis. Because TNBC is by definition unresponsive to endocrine therapy (eg, tamoxifen, aromatase inhibitors) and HER2-directed therapies (eg, trastuzumab), chemotherapy continues to play an important role. TNBC constitutes a molecularly heterogeneous group of tumors that can vary in response to treatment, and clinical management can be challenging, particularly for the practicing community oncologist, for whom breast cancer may be only one of many tumor types encountered. In January 2020, the Breast Cancer Therapy Expert Group (BCTEG) convened a roundtable discussion on the topic of advances in the treatment of TNBC. Topics discussed included histopathologic classification/definition of TNBC, neoadjuvant strategies, adjuvant chemotherapy (with special emphasis on management of patients who do not experience a pathologic complete response), and treatment of metastatic disease. Also reviewed was the wide range of emerging pathways and therapies currently under investigation to expand TNBC treatment options, including immunotherapies and poly(ADP-ribose) polymerase (PARP) inhibitors. This article summarizes the BCTEG discussion and highlights the key opinions relating to the treatment of patients with TNBC.

Case-Based Review and Clinical Guidance on the Use of Genomic Assays for Early-Stage Breast Cancer: Breast Cancer Therapy Expert Group (BCTEG)

In addition to classical clinicopathologic factors, such as hormone receptor positivity, human epidermal growth factor receptor 2 (HER2) status, and tumor size, grade, and lymph node status, a number of commercially available genomic tests may be used to help inform treatment decisions for early breast cancer patients. Although these tests improve our understanding of breast cancer and help to individualize treatment decisions, clinicians face challenges when deciding on the most appropriate test to order, and the advantages, if any, of one test over another. The Breast Cancer Therapy Expert Group (BCTEG) recently convened a roundtable meeting to discuss issues surrounding the use of genomic testing in early breast cancer, with the goal of providing practical guidance on the use of these tests by the community oncologist, for whom breast cancer may be only one of many tumor types they treat. The group recognizes that genomic testing can provide important prognostic (eg, risk for recurrence), and in some cases predictive, information (eg, benefit of chemotherapy, or extended adjuvant endocrine therapy), which can be used to help guide treatment decisions in breast cancer. The available tests differ in the types of information they provide, and in the patient populations and clinical trials that were conducted to validate them. We summarize the discussion of the BCTEG on this topic, and we also consider several patient cases and clinical scenarios in which genomic testing may, or may not, be useful to guide treatment decisions for the practicing community oncologist.

A Roundtable Discussion of the Breast Cancer Therapy Expert Group (BCTEG): Clinical Developments and Practice Guidance on Human Epidermal Growth Factor Receptor 2 (HER2)-positive Breast Cancer

Expression of human epidermal growth factor receptor 2 (HER2) in breast cancer defines a subset of patients (∼15%-20%) who are candidates for anti-HER2 therapies, most notably, trastuzumab, pertuzumab, antibody drug conjugates (eg, T-DM1), and tyrosine kinase inhibitor (TKI) drugs (eg, lapatinib and neratinib), all of which have dramatically changed the prognosis for this aggressive subtype of breast cancer. A roundtable meeting of the Breast Cancer Therapy Expert Group (BCTEG) was convened in March 2018 in an effort to discuss and clarify, from the perspective of the practicing community oncologist, recent developments in the diagnosis and treatment of HER2-positive (HER2⁺) breast cancer. Members of the group selected 4 key topics for discussion prior to the meeting, including diagnosis of HER2⁺ disease, and its treatment in the neoadjuvant, adjuvant, and metastatic settings. Approved testing methods, such as immunohistochemistry and fluorescence in situ hybridization, are used to demonstrate overexpression and/or amplification of HER2 in breast tumors, and established clinical guidelines are used to appropriately define treatment plans for patients with HER2⁺ disease. The panel acknowledges a range of treatment options now available for treatment of HER2⁺ breast cancer in the neoadjuvant, adjuvant, and advanced/metastatic settings, although it is noted that many controversies remain, including the optimal sequence of therapies, the most appropriate treatment(s) for subsets of patients with HER2⁺ disease (eg, hormone receptor-negative or -positive/HER2⁺), and uncertainties surrounding the diagnosis and definition of HER2⁺ disease. The current report summarizes the discussion of the BCTEG panel on this topic.