Abstract P2-12-06: Key factors influencing patient preferences for BRCA testing and adjuvant therapy in HER2-negative early breast cancer

Abstract Background: PARP inhibitors (PARPis) have survival benefits for women with high-risk HER2-negative early breast cancer (eBC) with germline BRCA mutations (BRCAm). Identifying patients eligible to receive PARPis can be challenging, as many individuals who are BRCAm carriers are unaware of their status, despite increasing availability of genetic testing. This study sought to identify factors that influence patient preferences for BRCA testing and adjuvant therapy. Methods: Women (≥18 years) in the United States with HER2-negative eBC were recruited between October 2023 - March 2024 via an online research panel to complete a cross-sectional survey. The survey included a Best-Worst-Scaling (BWS) exercise to identify barriers/facilitators to BRCAm testing among 16 factors. Two Discrete Choice Experiments (DCE) were included: one to evaluate preferences for BRCA testing by prompting patients to select between 2 hypothetical scenarios varying on 5 testing-related attributes (i.e., eligibility for targeted treatment, delays due to testing, information sharing with family, preventive surgery options, and out-of-pocket costs [OOPC]) and another to assess the influence of 7 treatment attributes on patients’ preferences for adjuvant therapy (i.e., invasive disease-free survival, whether the treatment is targeted, risk of nausea, risk of serious side effect [SSE], regimen, treatment duration, and monthly treatment OOPC) versus no treatment. Attributes included in the BWS and DCE exercises were informed by qualitative interviews with 20 healthcare providers and 12 patients. BWS and DCE attribute preference weights were calculated using hierarchical Bayesian modeling. Results: Women (N=360) on average were 61 years old and 77% were White; most resided in the South (37%) and Midwest (23%). Most women were first diagnosed with breast cancer after 2017 (72%), 61% were never tested for BRCAm or unsure of their status/testing history. Roughly one-third received adjuvant chemotherapy and another third received neoadjuvant chemotherapy. Relative to the other factors in the BWS, the top facilitators for BRCA testing were the possibility of test results showing eligibility for targeted therapy that may prevent or delay metastasis, having no OOPC for testing, and physician recommendation. OOPC of $250, potentially delaying treatment by 3-4 weeks and concerns that test results could lead to denial of life insurance/higher premiums were the top three barriers. The DCE evaluating preferences for BRCA testing showed that, on average, decreasing OOPC from $250 to no cost was most important, followed by learning if preventive surgery should be considered to prevent new cancer, and learning about eligibility for targeted treatment. The DCE on preferences for adjuvant therapy showed that 77% of the time, patients chose treatment over opting out, regardless of the combination of adjuvant treatment attributes shown. On average, reducing treatment OOPC from $900 to $0 influenced treatment choice most, followed by reducing risk of SSE from 77% to 24%, and having a BRCA-targeted treatment. Conclusions: Patients reported that a key benefit of BRCA testing was using the results to inform treatment decisions. Yet, OOPC may act as a barrier to testing. Patients’ decision to receive adjuvant therapy was influenced by the perceived effectiveness and tolerability of the therapy, and like BRCA testing, financial burden was a concern. Comprehensive patient-provider discussions regarding the benefits of testing including eligibility for innovative treatment may be an effective strategy for increasing BRCA testing and enhancing shared treatment decision-making. Selection of effective adjuvant treatment likely requires balanced consideration of medication tolerability and financial burden to the patient. Citation Format: Kathryn Mishkin, Kathleen Beusterien, Josh Lankin, Emily Mulvihill, Kathryn Krupsky, Alexandra Gordon, Xiaoqing Xu, Qixin Li, Jaime Mejia, Kim Hirshfield, Jagadeswara Rao Earla. Key factors influencing patient preferences for BRCA testing and adjuvant therapy in HER2-negative early breast cancer [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P2-12-06.