LAUSR

e12046 Background: OncotypeDX DCIS is a 12-gene assay designed to predict the 10-year risk of local recurrence and to guide treatment decisions, specifically the benefit of radiation therapy in breast ductal carcinoma in situ (DCIS). The test became available in December 2011 and is not currently recommended by guidelines. The Surveillance, Epidemiology and End Results (SEER) program captures cancer data at the population-level and has been conducting annual linkages with Genomic Health Clinical Laboratory, the only lab performing the test, to identify patients receiving the test. Methods: SEER cases diagnosed with in situ breast cancer (DCIS or papillary in situ) between 2011-2015 were included in the analysis. SEER data on patient demographics, tumor characteristics, and treatments were combined with linkage variables for OncotypeDX DCIS tests reported by Genomic Health. Logistic regression was used to identify which patient related factors were associated with having received the test and to evaluate the relationship between test generated risk categories and treatments. Results: Of the 68,826 in situ breast cancer cases, 2,155 were linked to DCIS test data. Test utilization increased from < 1% to 5.3% for patients diagnosed in 2011 vs. 2015. Patients were less likely to receive the test if they had larger and higher-grade tumors, were divorced, had Medicaid insurance, and were in the lowest socioeconomic status tertile. The majority of patients (68%) were at low risk, 17% intermediate, and 15% in the high risk group. Patients at intermediate or high risk were more likely to receive radiation (OR = 2.4, 95% CI: 1.8-3.2 and OR = 3, 95% CI: 2.3,4.1, respectively) than the low risk group. High risk patients were more likely than low risk patients to receive chemotherapy (OR = 4.3, 95% CI: 1.2, 14.4) and to undergo mastectomy than lumpectomy (OR = 1.47, 95% CI: 1.12-1.93). Conclusions: Clinical adoption of the OncotypeDX DCIS test has been slow. The association between multiple demographic factors and receiving the test indicated disparities in the US population. Clinical factors also influenced whether patients received the test. OncotypeDX DCIS results appeared to guide clinical decisions.