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.