Impact of Oncotype DX recurrence score in the management of breast cancer cases

Background Oncologists have used clinicopathologic features to guide treatment decisions for their breast cancer patients; however, more recently, results of multigene assays are also being considered. A popular assay, Oncotype DX (Genomic Health), stratifies node-negative breast cancer patients into groups that are at low, intermediate, or high risk for distant recurrence and guides decisions about adjuvant chemotherapy utilization. Objective We studied the impact of Oncotype DX recurrence score (ODxRS) compared with that of clinicopathologic features on adjuvant chemotherapy utilization in node-negative breast cancer patients and in node-positive breast cancer patients, and we evaluated whether clinicopathologic features impact the decision for adjuvant chemotherapy utilization in a subset of node-negative breast cancer patients with an intermediate-risk ODxRS. Methods A retrospective study from a single academic institution was performed on 425 patients with invasive breast carcinoma. Results Adjuvant chemotherapy utilization most significantly correlated with a high-risk ODxRS (P <.0001) and, to a lesser degree, patient's age and tumor size. No statistically significant association was found between ODxRS and adjuvant chemotherapy utilization in a subset of patients. In the 156 node-negative breast cancer patients with intermediate-risk ODxRS, high tumor grade most significantly correlated with adjuvant chemotherapy utilization (P <.0001). Conclusion ODxRS, if available, heavily impacts adjuvant chemotherapy utilization and more so than any clinicopathologic factor in node-negative breast cancer patients. Node-negative breast cancer patients in the intermediate-risk group whose tumors were high grade were more likely to receive adjuvant chemotherapy.