Breast oncology precision medicine: Genomic testing and treatment at the population level.

Abstract

288 Background: The 21-gene assay used to estimate breast cancer recurrence and tailor chemotherapy (chemo) receipt has demonstrated predictive validity and clinical utility. Yet it is unclear how involved patients are in the decision to perform the test, or how oncologists use results to recommend systemic chemo. We examined the patient experience with assay testing, physician recommendations, and chemo receipt based on test results. Methods: The iCanCare study surveyed a weighted random sample of newly diagnosed patients with early-stage breast cancer who were treated in 2013-14, identified through the population-based SEER registries of Los Angeles and Georgia about 3 months after surgical treatment, and merged with SEER data (N=2632, RR=70%). Registries partnered with Genomic Health, Inc. to link assay results to patients. We examined validated results against patient self report; patient satisfaction with testing and chemo decisions (1= not at all satisfied; 5= very satisfied); physician chemo recommendations, and; chemo receipt based on test scores (0-10= low risk; 30-100= high risk for recurrence). Results: Of the 1,908 women with invasive disease, 1,307 (68.5%) women had lower-risk features (Stage 1a/b, 2a, ER-positive, HER-2 negative) and 695 (53.2%) of them had tests performed. Of those tested, 60% recalled scores accurately. Most women were satisfied with their communication with doctors about testing (93%) and the chemo decision (90%). Testing varied slightly across risk groups: Grade 1 or 2 disease (54%), Grade 3 disease (61%), and any node-positive disease (62%). Most (91%) women with high-risk scores (>30) reported their oncologist recommended chemo. Fewer (65%) women with low-risk scores (<10) reported recommendations against chemo. Chemo receipt rates varied by risk scores: 2% for low-risk scores and 66% for high-risk scores. Conclusions: Most women were satisfied with testing and chemo decisions, yet many patients do not accurately recall test scores. Testing is higher in uncertain clinical groups. Physician recommendations and chemo receipt are tightly linked to test scores, suggesting that precision medicine has tailored treatment effectively to women with breast cancer. Funding: P01CA163233