A meta-analysis of clinical trials comparing taxane containing chemotherapy with non-taxane containing chemotherapy for women following surgery for early breast cancer

Breast cancer is by far the most frequent cancer experienced by women (23% of all cancers in women), with an estimated 1.15 million new cases and over 411,000 deaths reported worldwide in 2002. Early breast cancer is cancer that has not spread beyond the breast or nearby lymph nodes and is potentially curable with surgery alone. There is a risk that following surgery the breast cancer may return. Chemotherapy (anti-cancer drugs) given after surgery can reduce the risk of breast cancer returning and a combination of chemotherapy drugs (rather than one drug by itself) is typically used. Chemotherapy that includes a taxane drug may improve survival and disease-free survival for selected women with early breast cancer when administered following surgery. Paclitaxel and docetaxel are two of the chemotherapy drugs known as taxanes. Taxanes can inhibit cancer cells dividing and reproducing. Possible associated adverse effects include nausea, vomiting and increased risk of infections. In the 12 studies included in this review, a total of 21,191 women were randomised to treatment groups, 11069 to a taxane containing chemotherapy regimen and 10,122 to a non-taxane containing regimen. This review found that adjuvant chemotherapy which included a taxane drug lowered the risk of death and reduced the number of breast cancer recurrences. Further trials are needed to find the best way to use a taxane drug when it is given in combination with other non-taxane chemotherapy drugs.

Authors' conclusions: 

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.

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Background: 

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.

Objectives: 

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.

Search strategy: 

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.

Selection criteria: 

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

Data collection and analysis: 

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.

Main results: 

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.

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