Prospective Multicenter Study of the Impact of the 21-Gene Recurrence Score Assay on Medical Oncologist and Patient Adjuvant Breast Cancer Treatment Selection

PURPOSE: The 21-gene Recurrence Score (RS) assay has been validated to quantify the risk of distant recurrence in tamoxifen-treated patients with lymph node-negative, estrogen receptor-positive breast cancer and predict magnitude of chemotherapy benefit. This multicenter study was designed to prospectively examine whether RS affects physician and patient adjuvant treatment selection and satisfaction. PATIENTS AND METHODS: Before and after obtaining the 21-gene RS assay, medical oncologists stated their adjuvant treatment recommendation and confidence in it. Patients also indicated their treatment choice pre- and post-RS assay. Patients completed measures for decisional conflict, anxiety, and quality of life. RESULTS: Seventeen medical oncologists at one community and three academic practices consecutively enrolled 89 assessable patients. The medical oncologist treatment recommendation changed for 28 patients (31.%). Twenty-four patients (27%) changed their treatment decision. The largest change after the RS results was conversion from the medical oncologist's pretest recommendation for chemotherapy plus hormonal therapy (CHT) to post-test recommendation for hormone therapy (HT) in 20 cases (22.5%). Nine patients (10.1%) changed their treatment decision from CHT to HT. RS results increased medical oncologist confidence in their treatment recommendation in 68 cases (76%). Patient anxiety and decisional conflict were significantly lower after RS results. CONCLUSION: The results of this study indicate that the RS assay impacts medical oncologist adjuvant treatment recommendations, patient treatment choice, and patient anxiety.