21-gene Recurrence Score testing and subsequent treatment decisions in patients (pts) with estrogen-receptor-positive (ER+) early-stage breast cancer (ESBC).

Abstract

30 Background: The utilization of the 21-gene Recurrence Score (Oncotype DX) in community settings is now well established for ER+, node negative (N-) pts with ESBC. The utility of the Recurrence Score result is to guide treatment decisions and spare exposure to chemotherapy (CT) in pts that have little likelihood of benefitting. To better understand physician behavior as it relates to OncotypeDX testing, we examined the characteristics of pts tested versus not tested, the Recurrence Score distribution and treatment patterns in approximately 160 pts with ESBC seen in 2010. In addition, provider utilization and treatment patterns were also assessed. Methods: Using data from 2010, the number of pts who were eligible to undergo OncotypeDX testing was compared to the number of pts who underwent testing. Pts were considered eligible for testing if they had node-negative, ER+, HER2-negative ESBC. We determined the number of pts with a Recurrence Score value in the low (RS <18), intermediate (int; RS 18-30), and high-risk (RS ≥31) groups along with the number of pts who subsequently received chemotherapy in each category. Results: Of the 233 pts identified with ESBC, 158 were eligible for OncotypeDX testing and 107 (67.7%) underwent testing. Fifty-five percent of pts were low, 37% int, and 7.7% high-risk, respectively. Nineteen percent of low, 56% of int, and 100% of high-risk pts received CT. In the 11 pts with a low Recurrence Score result that received CT, the reason cited was pt decision in 4 and young age in 3. Conclusions: Oncotype DX use in the community is well established. Recurrence Score-guided use of CT in the low- and int-risk groups was as expected based on adjuvant chemotherapy guidelines; however, there were still some physicians treating low Recurrence Score pts with CT-mostly based on younger age or larger tumors. Data from 2011 and 2012 will be included in the final presentation allowing greater insight into pt groups less represented in the single year experience.