A quality improvement initiative on the utility of the Oncotype DX breast cancer assay in a community hospital.

Abstract

e13072 Background: Since the advent of Oncotype DX (ODX) breast recurrence score (RS) assay, the use of adjuvant chemotherapy (CT) in the treatment of breast cancer has significantly reduced. This test not only estimates the benefit of CT, but also determines the risk of distant recurrence in patients with early-stage breast cancer with hormone-receptor (ER/PR) positive, human epidermal growth factor receptor (HER) 2-negative, and axillary lymph node negative or positive (1-3 positive nodes) disease. All patients are categorized based on their scores ranging from 0-100 as follows: low (RS≤10), intermediate (RS11-25) and high risk (RS≥26). Further studies proved that adjuvant CT is beneficial in pre-menopausal women with RS 0-25, however offered no benefit to post-menopausal women in the same category. The aim of our study was to assess the implementation of these guidelines in a community hospital in an underserved area. Methods: At Mercy Catholic Medical Center, we performed a retrospective analysis on 303 female patients with newly diagnosed breast cancer, identified between January 2017 – October 2022. We included patients with ER/PR+, HER2-, lymph node negative or positive, who had undergone surgery and were to receive endocrine therapy with or without adjuvant CT. Patients who were lost to follow-up or did not undergo the genetic testing were excluded from the study. We then analyzed the treatment strategies based on RS categories. All patients who did not receive CT was either because it was not indicated (old age, post-menopausal) or patients refused. Results: 81 patients underwent ODX testing among whom, 60.5%, 35.8%, and 3.7% patients were Black, White and Hispanic/Asian, respectively. 1.2%, 9.8%, 18.51%, 34.56%, 35.08% were aged ≤40, 41-50, 51-60, 61-70 and ≥71 years, respectively. Based on the RS, we identified 29.62% in low risk, 56.79% in intermediate risk, and 13.5% in high-risk categories. 100% patients in the high-risk category were prescribed CT and only 7.4% patients with RS 0-25 received CT. 12 patients were found to be lymph node positive, among whom, 3 had RS≥26 and 2 were pre-menopausal, all of whom were prescribed CT. Out of these, 7 were post-menopausal with RS 0-25 and only 1 received CT. Conclusions: Our hospital data suggests that implementation of ODX and adherence to its guidelines has significantly helped avoid CT and its related side effects in the low and intermediate risk categories. Implementation of this cost-effective test has consistently increased in the last two decades and is now an imperative tool in clinical decision-making specially in community hospitals serving underprivileged populations. [Table: see text]