Taxanes for adjuvant treatment of early breast cancer

BACKGROUND

Adjuvant chemotherapy improves survival in premenopausal and postmenopausal women with early breast cancer. Taxanes are highly active chemotherapy agents used in metastatic breast cancer. Review authors examined their role in early breast cancer. This review is an update of a Cochrane Review first published in 2007.

OBJECTIVES

To assess the effects of taxane-containing adjuvant chemotherapy regimens for treatment of women with operable early breast cancer.

SEARCH METHODS

For this review update, we searched the Specialised Register of the Cochrane Breast Cancer Group, MEDLINE, Embase, CENTRAL (2018, Issue 6), the WHO International Clinical Trials Registry Platform (ICTRP), and ClinicalTrials.gov on 16 July 2018, using key words such as 'early breast cancer' and 'taxanes'. We screened reference lists of other related literature reviews and articles, contacted trial authors, and applied no language restrictions.

SELECTION CRITERIA

Randomised trials comparing taxane-containing regimens versus non-taxane-containing regimens in women with operable breast cancer were included. Studies of women receiving neoadjuvant chemotherapy were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias and quality of the evidence using the GRADE approach. Hazard ratios (HRs) were derived for time-to-event outcomes, and meta-analysis was performed using a fixed-effect model. The primary outcome measure was overall survival (OS); disease-free survival (DFS) was a secondary outcome measure. Toxicity was represented as odds ratios (ORs), and quality of life (QoL) data were extracted when present.

MAIN RESULTS

This review included 29 studies (27 full-text publications and 2 abstracts or online theses). The updated analysis included 41,911 randomised women; the original review included 21,191 women. Taxane-containing regimens improved OS (HR 0.87, 95% confidence interval (CI) 0.83 to 0.92; high-certainty evidence; 27 studies; 39,180 women; 6501 deaths) and DFS (HR, 0.88, 95% CI 0.85 to 0.92; high-certainty evidence; 29 studies; 41,909 women; 10,271 reported events) compared to chemotherapy without a taxane. There was moderate to substantial heterogeneity across studies for OS and DFS (respectively).When a taxane-containing regimen was compared with the same regimen without a taxane, the beneficial effects of taxanes persisted for OS (HR 0.84, 95% CI 0.77 to 0.92; P < 0.001; 7 studies; 10,842 women) and for DFS (HR 0.84, 95% CI 0.78 to 0.90; P < 0.001; 7 studies; 10,842 women). When a taxane-containing regimen was compared with the same regimen with another drug or drugs that were substituted for the taxane, a beneficial effect was observed for OS and DFS with the taxane-containing regimen (OS: HR 0.80, 95% CI 0.74 to 0.86; P < 0.001; 13 studies; 16,196 women; DFS: HR 0.83, 95% CI 0.78 to 0.88; P < 0.001; 14 studies; 16,823 women). Preliminary subgroup analysis by lymph node status showed a survival benefit with taxane-containing regimens in studies of women with lymph node-positive disease only (HR 0.83, 95% CI 0.78 to 0.88; P < 0.001; 17 studies; 22,055 women) but less benefit in studies of women both with and without lymph node metastases or with no lymph node metastases. Taxane-containing regimens also improved DFS in women with lymph node-positive disease (HR 0.84, 95% CI 0.80 to 0.88; P < 0.001; 17 studies; 22,055 women), although the benefit was marginal in studies of women both with and without lymph node-positive disease (HR 0.95, 95% CI 0.88 to 1.02; 9 studies; 12,998 women) and was not apparent in studies of women with lymph node-negative disease (HR 0.99, 95% CI 0.86 to 1.14; 3 studies; 6856 women).Taxanes probably result in a small increase in risk of febrile neutropenia (odds ratio (OR) 1.55, 95% CI 0.96 to 2.49; moderate-certainty evidence; 24 studies; 33,763 women) and likely lead to a large increase in grade 3/4 neuropathy (OR 6.89, 95% CI 3.23 to 14.71; P < 0.001; moderate-certainty evidence; 22 studies; 31,033 women). Taxanes probably cause little or no difference in cardiotoxicity compared to regimens without a taxane (OR 0.87, 95% CI 0.56 to 1.33; moderate-certainty evidence; 23 studies; 32,894 women). Seven studies reported low-quality evidence for QoL; overall, taxanes may make little or no difference in QoL compared to chemotherapy without a taxane during the follow-up period; however, the duration of follow-up differed across studies. Only one study, which was conducted in Europe, provided cost-effectiveness data.

AUTHORS' CONCLUSIONS

This review of studies supports the use of taxane-containing adjuvant chemotherapy regimens, with improvement in overall survival and disease-free survival for women with operable early breast cancer. This benefit persisted when analyses strictly compared a taxane-containing regimen versus the same regimen without a taxane or the same regimen with another drug that was substituted for the taxane. Preliminary evidence suggests that taxanes are more effective for women with lymph node-positive disease than for those with lymph node-negative disease. Considerable heterogeneity across studies probably reflects the varying efficacy of the chemotherapy backbones of the comparator regimens used in these studies. This review update reports results that are remarkably consistent with those of the original review, and it is highly unlikely that this review will be updated, as new trials are assessing treatments based on more detailed breast cancer biology.

Protein expression, survival and docetaxel benefit in node-positive breast cancer treated with adjuvant chemotherapy in the FNCLCC-PACS 01 randomized trial

INTRODUCTION

The PACS01 trial has demonstrated that a docetaxel addition to adjuvant anthracycline-based chemotherapy improves disease-free survival (DFS) and overall survival of node-positive early breast cancer (EBC). We searched for prognostic and predictive markers for docetaxel's benefit.

METHODS

Tumor samples from 1,099 recruited women were analyzed for the expression of 34 selected proteins using immunohistochemistry. The prognostic and predictive values of each marker and four molecular subtypes (luminal A, luminal B, HER2-overexpressing, and triple-negative) were tested.

RESULTS

Progesterone receptor-negativity (HR = 0.66; 95% CI 0.47 to 0.92, P = 0.013), and Ki67-positivity (HR = 1.53; 95% CI 1.12 to 2.08, P = 0.007) were independent adverse prognostic factors. Out of the 34 proteins, only Ki67-positivity was associated with DFS improvement with docetaxel addition (adjusted HR = 0.51, 95% CI 0.33 to 0.79 for Ki67-positive versus HR = 1.10, 95% CI 0.75 to 1.61 for Ki67-negative tumors, P for interaction = 0.012). Molecular subtyping predicted the docetaxel benefit, but without providing additional information to Ki67 status. The luminal A subtype did not benefit from docetaxel (HR = 1.16, 95% CI 0.73 to 1.84); the reduction in the relapse risk was 53% (HR = 0.47, 95% CI 0.22 to 1.01), 34% (HR = 0.66, 95% CI 0.37 to 1.19), and 12% (HR = 0.88, 95% CI 0.49 to 1.57) in the luminal B, HER2-overexpressing, and triple-negative subtypes, respectively.

CONCLUSIONS

In patients with node-positive EBC receiving adjuvant anthracycline-based chemotherapy, the most powerful predictor of docetaxel benefit is Ki67-positivity.

Recent advances in systemic therapy: advances in adjuvant systemic chemotherapy of early breast cancer

Adjuvant treatment for early breast cancer is an evolving field. Since the advent of the initial cyclophosphamide, methotrexate and 5-fluorouracil (CMF) regimens, which reduced risk for recurrence and death, anthracyclines and subsequently taxanes were added to the cytotoxic armamentarium for use sequentially or in combination in the adjuvant setting. The efficacy and toxicity of each chemotherapy regimen must be viewed within the context of host co-morbidities and the specific biologic phenotype of the tumor. In the era of mammographic screening, small, node-negative breast cancer is the most frequent presentation of the disease. Patient selection for adjuvant chemotherapy has become a key issue. Traditional prognostic factors continue to be of value in determining the risk for relapse, but new and sophisticated genomic tools (such as Oncotype Dx^® and Mammaprint^®) are now available and may improve our ability to select patients. For those patients who do require adjuvant chemotherapy, the 'one size fits all' paradigm should never again feature in the treatment of early breast cancer, following the important insights yielded by biomarker research to identify those who will benefit the most from a particular drug. In this review we focus on some of the current controversies and potential future steps in adjuvant chemotherapy for treatment of early breast cancer.