Taxanes for adjuvant treatment of early breast cancer

Abstract

Adjuvant chemotherapy improves survival in pre- and post-menopausal women with early breast cancer. Taxanes are highly active chemotherapy agents in metastatic breast cancer. Their role in early breast cancer was examined in this review. To review the randomised evidence comparing taxane containing chemotherapy regimens with non-taxane containing chemotherapy regimens as adjuvant treatment of pre- or post-menopausal women with early breast cancer. The Cochrane Breast Cancer Group Specialised Register was searched on 9th January 2007 using the codes for 'early breast cancer' and keywords for taxanes. Details of the search strategy used to create the register are described in the Group's module in The Cochrane Library. The reference lists of other related literature reviews and articles were also searched. Randomised trials comparing taxane containing regimens with non-taxane containing regimens in women with operable breast cancer. Women receiving neoadjuvant chemotherapy were excluded. Data were collected from published trials and abstracts. Studies were assessed for eligibility and quality and the data extracted independently by two review authors. Hazard ratios (HR) 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 and quality of life data were extracted when reported. We identified 20 studies, 12 of these (7 full publications, 5 abstracts) had sufficient data published for inclusion (11 for OS and 11 for DFS) in the review. The weighted average median follow up was 60.4 months. All studies fulfilled quality criteria either adequately or well. Amongst 18,304 women with 2483 deaths, the HR for OS was 0.81 (95% CI 0.75 to 0.88, P < 0.00001) favouring taxane containing regimens. Amongst 19,943 women with 4800 events, the HR for DFS was 0.81 (95% CI 0.77 to 0.86, P < 0.00001) favouring taxane containing regimens. There was no statistical heterogeneity for either OS or DFS. This meta-analysis of studies supports the use of taxane containing adjuvant chemotherapy regimens with improvement of overall survival and disease-free survival for women with operable early breast cancer. The review did not identify a subgroup of patients where taxane containing treatment may have been more or less effective. Dosage and scheduling of the taxane drug is not clearly defined and we await results of the next generation of studies to determine the optimal use of taxanes in early breast cancer.