Abstract PO3-29-05: Clinical risk score to predict overall survival and breast cancer recurrence in phase 3 TAILORx trial and the Surveillance, Epidemiology, and End Results (SEER) Database populations

Abstract

Abstract Background: Overall survival (OS) is the gold standard and most relevant endpoint in oncology research and patient care. It underscores a need to develop methods to estimate the likelihood of mortality in breast cancer. Methods: We evaluated molecular and clinical measures that predicted mortality risk using multiple logistic regression and developed a clinical risk score (CS) in 8,905 patients from the phase 3 TAILORx trial. Association of CS with mortality in patients at low, intermediate, and high risks was analyzed by Kaplan-Meier and multivariable Cox proportional-hazards regression analyses. The score was validated in an independent population of 148,301 patients with node-negative, hormone-receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer in the SEER database. Likelihood ratio (LR) test and c-index were used to compare prognostic information provided by CS and a 21-gene recurrence score (RS) to OS, invasive disease-free survival (DFS), recurrence-free interval (RFI), and distant recurrence-free interval (dRFI). Results: The 10-year mortality rates in low-risk, intermediate risk, and high-risk groups were 3.9% (95% CI 3.1 to 4.8), 37.2% (95% CI 23.4 to 51.1), and 75.8% (95% CI 54.1 to 97.4), respectively (P< 0.0001). Compared with low-risk score, intermediate (adjusted HR 45.5, 95% CI 32.2 to 64.9) and high-risk scores (HR 2026, 95% CI 1194 to 3483) were associated with risk of mortality, independent of demographics, tumor grade, RS, tumor size, PR, and treatment factors. The algorithm also predicted DFS, dRFI, and RFI outcomes (P< 0.0001 each), outperforming RS by both LR test and c-index estimate. Its validity was corroborated in the SEER population (intermediate risk: HR 9.3, 95% CI 6.7 to 13.3 and high-risk: HR 125.9, 95% CI 85.2 to 189.6). Conclusions: Clinical risk score robustly predicts risk of mortality in early-stage breast cancer populations. It provides more prognostic information than RS to survival and breast cancer recurrences. Citation Format: Sherry Yang, John Yu, Ninet Sinaii. Clinical risk score to predict overall survival and breast cancer recurrence in phase 3 TAILORx trial and the Surveillance, Epidemiology, and End Results (SEER) Database populations [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-29-05.