Validation of the online PREDICT tool in a cohort of early breast cancer in Brazil

PREDICT is a tool designed to estimate the benefits of adjuvant therapy and the overall survival of women with early breast cancer. The model uses clinical, histological, and immunohistochemical variables. This study aimed to evaluate the model's performance in a Brazilian population. We assessed the discrimination and calibration of the PREDICT model to estimate overall survival (OS) in five and ten years of follow-up in a cohort of 873 women with early breast cancer diagnosed from January 2001 to December 2016. A total of 743 patients had estrogen receptor (ER)-positive and 130 had ER-negative tumors. The area under the receiver operating characteristic (ROC) curve (AUC) for discrimination was 0.72 (95%CI: 0.66–0.78) at five years and 0.67 (95%CI: 0.61–0.72) at ten years for women with ER-positive tumors. The AUC was 0.72 (95%CI: 0.62–0.81) at five years and 0.67 (95%CI: 0.54–0.77) at ten years for women with ER-negative tumors. The predicted survival in ER-positive tumors was 91.0% (95%CI: 90.2–91.6%) at five years and 79.3% (95%CI: 77.7–81.0%) at ten years, and the observed survival 90.7% (95%CI: 88.6–92.9%) and 77.2% (95%CI: 73.4–81.4%), respectively. The predicted survival in ER-negative tumors was 84.5% (95%CI: 82.5–86.6%) at five years and 75.0% (95%CI: 71.6–78.5%) at ten years, and the observed survival 76.3% (95%CI: 69.1–84.3%) and 67.9% (95%CI: 58.6–78.6%), respectively. In conclusion, PREDICT was accurate to estimate OS in women with ER-positive tumors and overestimated the OS in women with ER-negative tumors.