Adoption of Gene Expression Profiling for Breast Cancer in US Oncology Practice for Women Younger Than 65 Years

Abstract

Background Four practice guidelines incorporate the use of gene expression profiling (GEP) tests for early-stage, hormone-receptor positive, HER2 negative breast tumors. Few studies describe factors associated with GEP testing in US oncology practice. We assessed the relationship between clinical, demographic, and group-level socioeconomic variables and test use in women under age 65. Patients and Methods Data from five state cancer registries were linked with insurance claims data and GEP test results. We assessed rates of testing and variables associated with test use in an incident cohort of 9444 commercially-insured women under age 65, newly-diagnosed with Stage I or II hormone-receptor positive breast cancer from 2006–2012. Results Rates of testing for women with N0 disease increased from 20.4% in 2006 to 35.2% in 2011. Variables associated with higher rates of testing, beyond clinical factors such as nodal status (P < .001), included being diagnosed from 2008–2012 vs. 2006–2007 (adjusted odds ratio, 1.67; 95% CI, 1.47 to 1.90), having preexisting comorbidities (adjusted odds ratio, 1.35; 95% CI, 1.14 to 1.59), and higher out-of-pocket pharmacy costs (adjusted odds ratio, 1.66; 95% CI, 1.40 to 1.97). Women under age 50 were more likely to be tested if they had Stage I vs. Stage II disease (P < .0001). Conclusions In an insured population of women under age 65, GEP testing increased following its inclusion in guidelines and mounting evidence. Additional research is needed to better understand oncologists’ decision not to order GEP testing for their patients who are otherwise eligible.

Endocrine therapy initiation, discontinuation and adherence and breast imaging among 21-gene recurrence score assay-eligible women under age 65

“…This, in light of our findings of significantly higher initiation rates among tested vs. untested women, implies lower quality of care and non-adherence to clinical guidelines in the care of some women. Alternately, these differences in the tested vs. untested group may reflect a strong selection effect for testing, as we have previously reported that clinical markers were strongly associated with test use [10]. …”

“…Details of data linkages have been presented previously [10]. Briefly, our linked database consists of five state cancer registries containing clinical and pathological variables linked with claims data from HealthCore’s Integrated Research Database (HIRD SM ).…”

“…Clinical guidelines for these women now include results from genomic expression profiling (GEP) tests, such as the Onco type DX® Breast Recurrence Score® (RS) [5–7], to refine recurrence risk estimates and guide treatment selection. These guidelines have led to broad dissemination and integration of such tests into routine oncology care [8–10]. In the absence of genomic profiling, combined chemo-endocrine therapy is recommended for most of these patients [11].…”

Impact of genomic testing and patient-reported outcomes on receipt of adjuvant chemotherapy

“…Multiple recent studies demonstrate continued adoption of genomic testing in breast cancer treatment decision making [5–7]. As research continues on the clinical utility of genomic tests, significant challenges arise in effectively communicating this risk information to patients and integrating this information with patient preferences to inform treatment decisions.…”

Racial and Ethnic Disparities in Oncotype DX Test Receipt in a Statewide Population-Based Study

“…Fewer studies have measured disparities in uptake by patients of Hispanic ethnicity, with some findings showing decreased use 24 and others reporting no difference compared with non-Hispanic whites. 25 Other studies of access to healthcare have found that Hispanics in the United States experience decreased access to care, similar to African Americans. 26,27 To address these contradictory findings and gaps in the research, recent population-based data are needed.…”