Utilization of Oncotype DX in an Inner City Population: Race or Place?

Oncotype DX, a 21-gene-array analysis, can guide chemotherapy treatment decisions for women with ER+ tumors. Of 225 ER+ women participating in a patient assistance trial, 23% underwent Oncotype DX testing: 31% of whites, 21% of blacks, and 14% of Hispanics ( ) were tested. Only 3 white women were treated at municipal hospitals and none was tested. 3% of women treated in municipal hospital as compared to 30% treated at tertiary referral centers were tested ( ). Within tertiary referral centers, there was no racial difference in testing: 32% of whites, 29% of blacks, and 19% of Hispanics ( ). Multivariate analysis (model c-statistic = 0.76; ) revealed that women who underwent testing were more likely to have stage 1B ( ; 95% CI: 1.45–1.85) and to be treated after 2007 ( ; 95% CI: 1.01–1.65) and less likely to be treated at a municipal hospital ( ; 95% CI: 0.04–0.94). Women treated at municipal hospitals were less likely to undergo testing resulting in a misleading racial disparity that is driven by site of care. As Oncotype DX can reduce overuse of chemotherapy, it is imperative to expand testing to those who could benefit from yet experience underuse of this test, namely, women treated at safety net hospitals. This trial is registered with NCT00233077. 1. Introduction While women with early stage breast cancer frequently receive adjuvant chemotherapy to prevent recurrence, not all patients benefit from and require it. Oncotype DX (ODX) (Genomic Health, Inc., Redwood City, CA) is a validated genomic predictor of outcome and response to chemotherapy in estrogen-receptor- (ER-) positive and node-negative breast cancer. ODX analyzes the expression of 21 genes within a tumor to determine a recurrence score that corresponds to a specific likelihood of breast cancer recurrence within 10 years of the initial diagnosis, as well as response to adjuvant treatment. Results are reported as a numeric recurrence score (RS) divided into low, intermediate, and high risk groups. Patients with a high RS derive additional benefit from chemotherapy to hormonal therapy, while those with a low score do not. Thus, the assay has the potential to enable women to avoid unnecessary chemotherapy. The assay, costing approximately $4500, has been available since 2004, with Medicaid coverage becoming available in 2007. The American Society for Clinical Oncology and the National Comprehensive Cancer Network include the 21-gene signature assay in their guidelines for the management of lymph node-negative and ER-positive breast cancer [1, 2] The cost effectiveness of this assay in