Abstract P6-09-10: Provider characteristics and receipt of oncotype Dx testing in women diagnosed with early stage breast cancer using SEER-Medicare data
Authors: Dinan MA , Wilson LE , Greiner M , Pollack CE 
Published: February 2018

Background: Oncotype DX (ODX) genomic testing to evaluate recurrence risk and benefit of adjuvant chemotherapy in patients with ER-positive, node-negative breast cancers was approved for Medicare reimbursement in 2006. We previously examined patient-level factors associated with utilization of ODX testing from 2005-2009 in the SEER-Medicare population; ODX testing occurred most frequently in patients with ER+, node negative disease, with 80% of all tests occurring in patients aged 66-75. In our current study, we examined potential provider factors associated with patient-level ODX testing from 2008 to 2012.

Methods: Using a retrospective cohort design, we identified all individuals who had a SEER diagnosis of breast cancer from 2008-2011 and were enrolled in fee-for-service Medicare parts A and B for one year before and one year after diagnosis. We limited our analysis to individuals who had surgical resection of their breast tumor within 4 months of diagnosis and had a breast tumor which was ER+, invasive, and non-metastatic to capture the eligible patient population. Using Medicare claims data linked with the AMA physician dataset (which includes AMA members and non-members), we identified physician characteristics of the primary breast surgeon and medical oncologist including specialty, gender, years in practice, case volume, utilization of chemotherapy, and whether they serve rural populations. For patients with an ODX test, we used the identification on the claim to link to the performing provider. We examined the associations between provider characteristics and patient receipt of ODX testing using unadjusted and adjusted logistic regression models. Adjusted models included patient demographic and clinical characteristics.

Results: We identified 24,463 eligible breast cancer patients who received their care from 3172 primary surgeons and 2475 medical oncologists. Of 4124 ODX tests ordered for patients in the study, 70% were ordered by the assigned medical oncologist and 16% were ordered by the breast surgeon. In multivariable regression models, multiple physician characteristics were associated with receipt of ODX testing including having an assigned medical oncologist (OR 2.77, 95% CI 2.00-3.82), having a surgeon with a specialty of surgical oncology (OR 1.20, 95% CI 1.09-1.31), having a female medical oncologist (OR 1.10 95% CI 1.02-1.20). Having a medical oncologist with ≥5 years in practice was associated with lower odds of testing (OR 0.83 95% CI 0.76-0.92). Breast surgery performed at an academic hospital was associated with higher odds of ODX testing (OR 1.11 95% CI 1.02-1.20).

Conclusion: The majority of ODX testing for indicated breast cancer patients is ordered by medical oncologists, though surgeons and physicians of other specialties also order the tests in practice. Physician characteristics including gender and time in practice appear to affect a patient's likelihood of receiving ODX testing, creating opportunities for targeting interventions to help women with breast cancer receive optimal care.

Citation Format: Dinan MA, Wilson LE, Greiner M, Pollack CE. Provider characteristics and receipt of oncotype Dx testing in women diagnosed with early stage breast cancer using SEER-Medicare data [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-09-10.