Abstract PS5-04-04: Design of a Prospective Registry Study to Evaluate the Decision Impact and Clinical Utility of the Lipidomic-based Blood Test BREASTEST Plus in Breast Cancer Screening

Abstract Background: BREASTEST Plus is a novel blood-based diagnostic assay used alongside imaging to support breast cancer screening decision-making. While prior validation studies have demonstrated the analytical and clinical performance of the assay, real-world evidence (RWE) on its clinical utility and long-term impact on patient outcomes remains essential. To address this, BCAL Diagnostics has initiated a prospective, observational registry study aimed at evaluating how BREASTEST Plus influences physician decision-making and patient outcomes in routine clinical practice. Methods: This multi-centre, prospective registry will enroll a minimum of 2,000 women across Australia who undergo BREASTEST Plus testing as part of their clinical assessment. Inclusion criteria are broad, reflecting routine clinical use, and will include both symptomatic and asymptomatic women aged ≥30 years. Treating clinicians will complete a structured decision-impact survey following receipt of results to assess how the assay influenced diagnostic or management decisions. Patients will be followed for up to five years, with key endpoints including one and two year sensitivity and specificity. Results: Primary endpoints are: (1) proportion of cases in which BREASTEST Plus results changed clinical management, and (2) concordance of assay results with cancer diagnoses over time. Secondary endpoints include reduction in unnecessary procedures, and patient-reported metrics. Interim analyses will be performed at 12-month intervals to inform clinical and regulatory stakeholders. Conclusion: This RWE registry is the first of its kind for a lipid-based breast cancer diagnostic and will provide critical insights into the utility, impact, and long-term value of BREASTEST Plus in everyday practice. Results will inform guidelines, reimbursement decisions, and broader adoption strategies across healthcare systems. Citation Format: S. Preston, S. Ryan, D. Speakman. Design of a Prospective Registry Study to Evaluate the Decision Impact and Clinical Utility of the Lipidomic-based Blood Test BREASTEST Plus in Breast Cancer Screening [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-04-04.