Abstract P1-13-06: The influence of the oncotype DX breast recurrence score on persistence to endocrine therapy in patients with low-risk ER/PR+ invasive breast cancer

Abstract Intro: The Oncotype DX breast recurrence score provides newly diagnosed patients with low-risk ER/PR+ invasive breast cancer with an estimation of their 10-year risk of distant recurrence if compliant with five years of endocrine therapy. Despite the well-established benefits of endocrine therapy, to include a decrease in local and distant disease recurrence, many patients will discontinue endocrine therapy prior to five years, defined as non-persistence. We hypothesized that the individual perception of risk of recurrence conveyed by the Oncotype DX breast recurrence score directly influences persistence with endocrine therapy and patients with higher Oncotype DX breast recurrence scores may have higher rates of persistence when compared to a similar cohort with lower recurrence scores. Further, we hypothesized that disease recurrence in women with low-risk (defined as less than 26) ER/PR+ breast cancer is due primarily to non-persistence with endocrine therapy. Methods: Our study included 198 patients with low-risk ER/PR+ breast cancer treated at a comprehensive cancer center between April 2011 and April 2014 with sufficient-follow-up data of at least 5 years. Persistence was determined by chart review and defined as a minimum duration of 55 months on endocrine therapy. Multivariable ANOVA and Fisher Chi Square Exact test were used to compare the recurrence score, 10-year risk of distant recurrence, and rates of recurrence between persistent vs non-persistent patients. Results: The average recurrence score of our cohort was 14.74 with an average 10-year risk of distant recurrence of 9.8 percent with five years of endocrine therapy. The average recurrence score was 15.24 in the persistent group vs. 13.18 for the non-persistent group (p=0.029). The average 10-year risk of distance recurrence was 10.1% in persistent patients vs 9% in non-persistent patients (p=0.019). The recurrence rate (both local and distant) was 4% in persistent patients vs 16% in non-persistent patients at 5- year follow (P=<0.01). Discussion: Non-persistence to endocrine therapy represents a major unmet need in breast cancer care. The Oncotype DX breast recurrence score significantly influences persistence to endocrine therapy as our retrospective review demonstrated that patients with low-risk ER/PR+ locally invasive breast cancer with higher Oncotype DX scores are more likely to complete the recommended 5-years of endocrine therapy. Further, despite having a lower average Oncotype DX score overall, the non-persistent group had a higher rate of recurrence when compared to the persistent group. This finding further substantiates the overall effectiveness of endocrine therapy in reducing the risk of future recurrence in patients with low-risk ER/PR+ breast cancer. Mindful framing of Oncotype DX test results by providers represents a potential avenue to increase persistence through the modulation of individual risk perception and may ultimately lead to decreased rates of disease recurrence in patients with low-risk ER/PR+ invasive breast cancer. Citation Format: Jonathan Pirruccello, Elaine Kuhn, Mary Chamberlin. The influence of the oncotype DX breast recurrence score on persistence to endocrine therapy in patients with low-risk ER/PR+ invasive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-13-06.