OBJECTIVES:
* To evaluate the association between the 21-gene Recurrence Score and risk of local-regional recurrence (LRR) in node-positive, estrogen receptor- (ER) positive (+) patients treated with cyclophosphamide and doxorubicin hydrochloride (AC) with or without paclitaxel in the NSABP-B-28 trial.
* To evaluate the potential for combining the 21-gene Recurrence Score (RS) with traditional clinico-pathologic factors in order to derive an improved algorithm for prediction of LRR risk and in order to identify subgroups of ER-positive patients with 1-3 or 4 or more positive nodes who do/do not need post mastectomy chest wall radiotherapy (XRT) or regional nodal XRT (irrespective of surgical procedure).
* To evaluate whether the 21-gene RS predicts benefit from adding paclitaxel to AC chemotherapy in reducing risk of LRR, and improving disease-free survival (DFS) and overall survival (OS) in node-positive, ER-positive patients from NSABP-B-28.
OUTLINE: RNA extracted from paraffin-embedded tissue samples are analyzed for gene expression profile by Ribogreen assay and RT-PCR. Results are then compared and analyzed with each patient clinical-pathologic factors, including tumor size, patient age, number of positive nodes (1-3, 4+), tumor grade, and surgery type (mastectomy or lumpectomy).
