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Summary: Background: The 21-gene recurrence score assay is prognostic for women with node-negative, oestrogen-receptor-positive breast cancer treated with tamoxifen. A low recurrence score predicts little benefit of chemotherapy. For node-positive breast cancer, we investigated whether the recurrence score was prognostic in women treated with tamoxifen alone and whether it identified those who might not benefit from anthracycline-based chemotherapy, despite higher risks of recurrence. Methods: The phase 3 trial SWOG-8814 for postmenopausal women with node-positive, oestrogen-receptor-positive breast cancer showed that chemotherapy with cyclophosphamide, doxorubicin, and fluorouracil (CAF) before tamoxifen (CAF-T) added survival benefit to treatment with tamoxifen alone. Optional tumour banking yielded specimens for determination of recurrence score by RT-PCR. In this retrospective analysis, we assessed the effect of recurrence score on disease-free survival by treatment group (tamoxifen vs CAF-T) using Cox regression, adjusting for number of positive nodes. Findings: There were 367 specimens (40% of the 927 patients in the tamoxifen and CAF-T groups) with sufficient RNA for analysis (tamoxifen, n=148; CAF-T, n=219). The recurrence score was prognostic in the tamoxifen-alone group (p=0·006; hazard ratio [HR] 2·64, 95% CI 1·33–5·27, for a 50-point difference in recurrence score). There was no benefit of CAF in patients with a low recurrence score (score <18; log-rank p=0·97; HR 1·02, 0·54–1·93), but an improvement in disease-free survival for those with a high recurrence score (score ≥31; log-rank p=0·033; HR 0·59, 0·35–1·01), after adjustment for number of positive nodes. The recurrence score by treatment interaction was significant in the first 5 years (p=0·029), with no additional prediction beyond 5 years (p=0·58), although the cumulative benefit remained at 10 years. Results were similar for overall survival and breast-cancer-specific survival. Interpretation: The recurrence score is prognostic for tamoxifen-treated patients with positive nodes and predicts significant benefit of CAF in tumours with a high recurrence score. A low recurrence score identifies women who might not benefit from anthracycline-based chemotherapy, despite positive nodes. Funding: National Cancer Institute and Genomic Health. [Copyright &y& Elsevier]

Summary: The neoadjuvant setting provides a unique opportunity to study the effect of systemic treatments on breast cancer biology and to identify clinically useful prognostic and predictive biomarkers. Discrepancies and inconsistencies in the use of definitions and endpoint assessments in this setting confound the analysis and interpretation of results across clinical trials and hinder research progress. This Review represents a joint effort of the Breast International Group and the National Cancer Institute-sponsored North American Breast Cancer Group to provide clinicians and researchers with a series of standardised definitions and endpoints that could be implemented in future neoadjuvant clinical trials. Definitions of the setting of interest and of survival endpoints are recommended, together with proposals for standard assessment of the response to treatment, use of functional and molecular imaging endpoints, and characterisation and selection of the population to treat. We expect that implementation of these recommendations will improve the conduct, reporting, and effectiveness of clinical trials and fully exploit the clinical and scientific potential of the neoadjuvant setting in breast cancer. [ABSTRACT FROM AUTHOR]