Decision curve analysis for the risk models for second primary breast cancer (BC). The decision curves shows that within the threshold probabilities ((A) 1.0% - 3.0% for 5-year and (B) 2.8% - 7.5% for 10-year prediction of second primary BC, respectively), using the competing-risk model to predict the probability of developing second primary BC can produce more benefit than treating either all or no patient would have second BC.