Practice Patterns and Outcomes for Hormone Receptor Positive and Node Negative Breast Cancer Patients with Intermediate Risk Oncotype Dx Scores: Analysis of the National Cancer Database.

553 Background: The advent of the Oncotype DX (ODX) test has widely affected chemotherapeutic treatment decisions in patients with early stage hormone receptor positive breast cancer. Patients with low risk (0-17) and high risk (31+) scores are often advised to forego or receive chemotherapy, respectively. There has been less clarity in patients with intermediate risk scores (18-30). The TAILORx trial was designed to determine whether patients with ODX scores of 11-25 benefit from chemotherapy. We utilized the same range and examined practice patterns and outcomes for patients from the National Cancer Database (NCDB). Methods: Women with hormone receptor positive and node negative breast cancer who received endocrine therapy and had ODX scores of 11-25 were identified in the NCDB from 2004-2013. A total of 14,752 patients were identified. We examined the impact of patient and treatment variables on receipt of chemotherapy using Cox regression and multivariate analysis. In a subset of patients (n = 4,757) that had a median of 4 years follow-up, we examined the impact of chemotherapy on overall survival (OS). Results: Factors that significantly correlated with receipt of chemotherapy included treatment at a community cancer program, younger age, race, private insurance, year of diagnosis, pathological grade, lymphovascular invasion, patients undergoing mastectomy, and patients undergoing radiation therapy (RT) (all p < 0.05). There was a decrease in patients receiving chemotherapy from 2009 to 2013 (31.0% to 18.4%, p < 0.001). Age, Charlson-Deyo co-morbidity index, tumor size, and RT were correlated with improved OS (all p < 0.05). In the subset of patients with a median follow up of 46.4 months, chemotherapy was not associated with a difference in OS (p = 0.89). Conclusions: Various socioeconomic and clinicopathologic factors were associated with the administration of adjuvant chemotherapy to patients with early stage hormone receptor positive breast cancer who had ODX scores between 11-25. For the subset of patients with a median follow-up of 4 years, receipt of chemotherapy was not associated with improved OS.