There were no significant differences in RFS & PFS rates between EORTC risk groups.
We constructed a novel recurrence risk classification using four clinical factors.
There was a significant difference in RFS rate between the novel risk groups.
Risk classification is essential in any medical treatment. It is constructed based on the large data of observed events such as recurrence and death. However different race/ethnic groups may not follow the prediction since genetic and environmental factors affect the events. Bladder cancer is a frequent cancer among men. We evaluated the commonly-used European risk classification of non-muscle invasive bladder cancer. Surprisingly, this risk classification did not segregate the Japanese patients well. In this study we developed and validated a novel risk model predicting recurrence. This risk classification will be useful among Asian patiens with non-muscle invasive bladder cancer.