Independent validation of the BRENDA-Score breast cancer prognosis prediction tool in Chinese patients

Background The BRENDA-Score was developed and used to predict the prognosis of patients with breast cancer (BC). This study was performed to validate the use of this tool in Chinese patients with primary invasive BC patients. Methods Patients underwent surgery for BC from January 2009 to December 2016. Discrimination was assessed by the area under the receiver operating characteristic (ROC) curve (AUC). Calibrations were assessed by comparing predicted and observed 5-year and 10-year metastasis-free survival (MFS) in the overall cohort and patient subgroups. Results A total of 2029 BC patients were enrolled. Kaplan–Meier analysis revealed significant differences in MFS risk groups (log-rank test P < 0.01). ROC analysis showed good accuracy for 5-year MFS (AUC 0.779) and fair accuracy for 10-year MFS (AUC 0.728). The BRENDA-Score accurately predicted 5-year and 10-year MFS in the entire cohort and in all other predefined subgroups, except for the 5-year MFS in the subgroup aged<40 years, which was overestimated (differences between the predicted and observed MFS were 6.7%, P < 0.05). The 5-year MFS rates of ER- positive and ER-negative patients were 90.9% and 80.6%, respectively (P < 0.05). The 10-year MFS rates of ER-positive and ER-negative patients were 78.0% and 73.7%, respectively (P = 0.25). Conclusions The BRENDA-Score accurately predicted 5-year and 10-year MFS. The results showed good validity, transportability, and potential clinical value. However, the results for 5-years MFS should be interpreted carefully in patients aged <40 years. After 10 years the value of the ER as a prognostic factor was less important. Micro abstract Accurate prediction of breast cancer (BC) is critical for clinical decision-making after early BC surgery. The validation of BRENDA-Score prediction model shows that it can be used as a reliable prediction tool for BC patients in China. ER may be helpful in early prediction of cancer, but its value as a prognostic factor will decrease after 10 years.