Second International Consensus Conference on Advanced Breast Cancer (ABC2), Lisbon, 11/09/2013: The German Perspective

Review of hormone-based treatments in postmenopausal patients with advanced breast cancer focusing on aromatase inhibitors and fulvestrant

Background

Endocrine therapy constitutes a central modality in the treatment of oestrogen receptor (ER)-positive advanced breast cancer.

Purpose

To evaluate the evidence for endocrine treatment in postmenopausal patients with advanced breast cancer focusing on the aromatase inhibitors, letrozole, anastrozole, exemestane and fulvestrant.

Methods

A review was carried out using PubMed. Randomised phase II and III trials reporting on ≥100 patients were included.

Results

35 trials met the inclusion criteria. If not used in the adjuvant setting, a non-steroid aromatase inhibitor was the optimal first-line option. In general, the efficacy of the different aromatase inhibitors and fulvestrant was similar in tamoxifen-refractory patients. A randomised phase II trial of palbociclib plus letrozole versus letrozole alone showed significantly increased progression-free survival (PFS) when compared with endocrine therapy alone in the first-line setting (20.2 vs 10.2 months). Furthermore, the addition of everolimus to exemestane in the Breast Cancer Trials of OraL EveROlimus-2 (BOLERO-2) study resulted in an extension of median PFS by 4.5 months after recurrence/progression on a non-steroid aromatase inhibitor. However, overall survival was not significantly increased.

Conclusion

Conventional treatment with an aromatase inhibitor or fulvestrant may be an adequate treatment option for most patients with hormone receptor-positive advanced breast cancer. Mammalian target of rapamycin (mTOR) inhibition and cyclin-dependent kinase 4/6 (CDK4/6) inhibition might represent substantial advances for selected patients in some specific settings. However, there is an urgent need for prospective biomarker-driven trials to identify patients for whom these treatments are cost-effective.

Phase II/III weekly nab-paclitaxel plus gemcitabine or carboplatin versus gemcitabine/carboplatin as first-line treatment of patients with metastatic triple-negative breast cancer (the tnAcity study): study protocol for a randomized controlled trial

BACKGROUND

Triple-negative breast cancer is an aggressive disease with unmet clinical needs. In a phase III study of patients with metastatic triple-negative breast cancer, first-line gemcitabine/carboplatin resulted in a median progression-free survival of 4.6 months. nab-paclitaxel-based regimens (with gemcitabine or carboplatin±bevacizumab) also demonstrated efficacy and safety in first-line phase II trials of human epidermal growth factor receptor 2-negative metastatic breast cancer.

TRIAL DESIGN

In this international, multicenter, open-label, randomized phase II/III trial, the efficacy and safety of first-line nab-paclitaxel with gemcitabine or with carboplatin will be compared with gemcitabine/carboplatin (control arm) for metastatic triple-negative breast cancer.

METHODS

In the phase II portion, 240 patients with measurable metastatic triple-negative breast cancer and treatment-naive for metastatic disease will be randomized 1:1:1 (stratified by disease-free interval: ≤1 versus>1 year) to nab-paclitaxel 125 mg/m2 plus gemcitabine 1000 mg/m2, nab-paclitaxel 125 mg/m2 plus carboplatin area under the curve 2 mg×min/mL, or gemcitabine 1000 mg/m2 plus carboplatin area under the curve 2 mg×min/mL, all given on days 1 and 8 of a 21-day cycle. Investigator-assessed progression-free survival (primary endpoint), overall response rate, overall survival, and safety will be assessed. A ranking algorithm of five efficacy and safety parameters will be used to pick the "winner" of the nab-paclitaxel regimens. In the phase III portion, 550 patients will be randomized 1:1 (stratified by disease-free interval: ≤1 versus >1 year, and prior adjuvant/neoadjuvant taxane use) to the nab-paclitaxel combination arm selected from the phase II portion or to the control arm. Patients in phase II will not be part of the phase III population. The phase III primary endpoint is blinded, independently-assessed progression-free survival; secondary endpoints include blinded, independently-assessed overall response rate, overall survival, disease control rate, duration of response, and safety. Biomarker and circulating tumor-cell exploratory analyses and quality-of-life assessments will also be performed. A list of approving ethical bodies was provided in Additional file 1.

DISCUSSION

The tnAcity trial aims to identify a new standard cytotoxic chemotherapy regimen for first-line treatment of metastatic triple-negative breast cancer.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01881230 . Date of registration: 17 June 2013.

Tamoxifen induces a pluripotency signature in breast cancer cells and human tumors

Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients that are eligible for adjuvant endocrine therapy. However, ∼50% of ERα-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment. Unfortunately, prediction of de novo resistance to endocrine therapy and/or assessment of relapse likelihood remain difficult. While several mechanisms regulating the acquisition and the maintenance of endocrine resistance have been reported, there are several aspects of this phenomenon that need to be further elucidated. Altered metabolic fate of tamoxifen within patients and emergence of tamoxifen-resistant clones, driven by evolution of the disease phenotype during treatment, appear as the most compelling hypotheses so far. In addition, tamoxifen was reported to induce pluripotency in breast cancer cell lines, in vitro. In this context, we have performed a whole transcriptome analysis of an ERα-positive (T47D) and a triple-negative breast cancer cell line (MDA-MB-231), exposed to tamoxifen for a short time frame (hours), in order to identify how early pluripotency-related effects of tamoxifen may occur. Our ultimate goal was to identify whether the transcriptional actions of tamoxifen related to induction of pluripotency are mediated through specific ER-dependent or independent mechanisms. We report that even as early as 3 hours after the exposure of breast cancer cells to tamoxifen, a subset of ERα-dependent genes associated with developmental processes and pluripotency are induced and this is accompanied by specific phenotypic changes (expression of pluripotency-related proteins). Furthermore we report an association between the increased expression of pluripotency-related genes in ERα-positive breast cancer tissues samples and disease relapse after tamoxifen therapy. Finally we describe that in a small group of ERα-positive breast cancer patients, with disease relapse after surgery and tamoxifen treatment, ALDH1A1 (a marker of pluripotency in epithelial cancers which is absent in normal breast tissue) is increased in relapsing tumors, with a concurrent modification of its intra-cellular localization. Our data could be of value in the discrimination of patients susceptible to develop tamoxifen resistance and in the selection of optimized patient-tailored therapies.

Systemic treatment approaches in her2-negative advanced breast cancer-guidance on the guidelines

Despite advancements in the treatment of early-stage breast cancer, many patients still develop disease recurrence; others present with de novo metastatic disease. For most patients with advanced breast cancer, the primary treatment intent is noncurative-that is, palliative-in nature. The goals of treatment should therefore focus on maximizing symptom control and extending survival. Treatments should be evaluated on an individualized basis in terms of evidence, but also with full respect for the wishes of the patient in terms of acceptable toxicity. Given the availability of extensive reviews on the roles of endocrine therapy and her2 (human epidermal growth factor receptor 2)-targeted therapies for advanced disease, we focus here mainly on treatment guidelines for the non-endocrine management of her2-negative advanced breast cancer in a Canadian health care context.

Systemic treatment for breast cancer: chemotherapy and biotherapy agents

OBJECTIVES

To describe current systemic chemotherapy and biotherapy breast cancer treatments to better inform clinical nursing practice.

DATA SOURCES

CINAHLl, Medline, Academic Research Periodicals, PubMed Clinical Queries, CANCERLIT, and EBM Reviews-Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews (CDSR).

CONCLUSION

Systemic therapeutic options for patients with breast cancer can be complex and varied. Furthermore, the guidelines for the treatment of breast cancer are frequently changing as new chemotherapies and biotherapies are being developed.

IMPLICATIONS FOR NURSING PRACTICE

Nursing clinical practice has to remain current to accommodate new treatments and the side effect profiles. This knowledge is essential to providing evidence-based care for breast cancer patients receiving these treatments.