Validation of RecurIndex (RI) for patients with early-stage breast cancer enrolled in a Taiwanese multicenter study.

Abstract

3560 Background: Numerous prospective studies, predominantly in Caucasian population, have proven the clinical utility of using multigene expression tests to prevent overtreatment in early breast cancer (EBC) patients. Since racial and ethnic disparities exist in genetic and biological factors that could influence the disease, the primary purpose of this study is to access the clinical utility of RecurIndex, a recurrence risk test, that is based on a genomic profiling derived from Asian women. Methods: A total of 298 patients with EBC, luminal subtype (85.6%), HER2 subtype (7.7%) and triple-negative subtype (6.7%), were enrolled in a retrospective study across Taiwan medical centers. Kaplan Meier and Cox Proportional Hazards model were used to, respectively, identify independent prognostic factors and calculate the survival rates. The prediction model was then tested using the area under the receiver operating characteristic curve (AUC). The primary endpoint was distant recurrence-free survival (DRFS). Results: The 10-year DRFS was significantly higher in the good-prognosis group than the poor-prognosis group (92.0% [95% CI, 86.1-98.2] versus 63.0% [95% CI, 49.9-79.5]) (Table). The overall hazard ratio for distant recurrence was 1.031 (95% CI, 1.017±1.046) per RI score increment. In addition, in a subset of 179 cases (60.1%), the model yielded an 82.3% correct classification rate for predicting DR with a sensitivity of 87.0%, a specificity of 68.6% and negative predictive values of 97.3%. Conclusions: The present study provides robust evidence of the clinical utility of RI-DR to predict clinical outcomes. RecurIndex could be used to determine the utility of chemotherapy in Asian patients, especially in hormone-receptor positive and HER2 negative disease, leading to a meaningful reduction in adjuvant chemotherapy recommendations. [Table: see text]