Abstract LB119: Recurrence score for recurrence over survival outcome in the landmark TAILORx trial

Abstract

Abstract Overall survival is the most relevant endpoint in clinical research and patient care. Nonetheless, cancer recurrence has been frequently utilized as a surrogate endpoint, particularly in the context of multi-gene assays and molecular signatures. The 21-gene recurrence score (RS) was originally established against distant recurrence for prognosis in breast cancer. However, it is unclear whether RS has a weight for the recurrence over survival prognosis. We investigated RS on the choice of clinical endpoints in the Trial Assigning Individualized Options for Treatment (TAILORx), which had OS, invasive disease-free survival (DFS), and recurrence-free interval (RFI) in addition to distant recurrence-free interval as the clinical endpoints. Both midrange (11-25) and high-range (26-100) scores were associated with RFI, high-range only with DFS, but not significantly associated with OS in the multivariable Cox proportional-hazards regression models. Of 462 death events, 33.1% (153 events) were ascribed to breast cancer and 91.8% (424) were due to DFS-related events that included 24.5% other cancers, 34.2% unknown and 33.1% breast cancer. It is DFS that was wound up as the most representative surrogate endpoint for survival. The lack of survival significance was probably due to the nature of 21-gene assay weighted for recurrence rather than not having enough event numbers in the TAILORx clinical trial. The data call for establishing biomarkers directly towards OS or DFS to increase survival with more precision. Citation Format: Sherry X. Yang, John Yu, Molin Wang. Recurrence score for recurrence over survival outcome in the landmark TAILORx trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB119.