Substratification of patients with highest‐risk non‐muscle invasive bladder cancer helps to identify the candidates for immediate radical cystectomy: A two‐center study

Objectives Performing immediate radical cystectomy in all patients with the highest‐risk non‐muscle invasive bladder cancer results in overtreatment. We confirm whether the substratification of highest‐risk patients can more effectively select suitable patients for radical cystectomy. Methods Patients with primary T1 high grade bladder cancer from two centers were included and roughly stratified into high‐risk or highest‐risk. The highest‐risk patients were further substratified according to the number of risk factors. Endpoints were tumor recurrence and progression. The predictive accuracy was assessed with internal validation that consists of time‐dependent receiver operating characteristic curve and calibration curves. Results A total of 262 patients were included. Although highest‐risk patient had a poor prognosis, after further substratification, we found that those with only one factor showed the same prognosis with high‐risk patients (recurrence: hazard ratio 1.79, P = 0.105; progression: hazard ratio 1.38, P = 0.532), while those with ≥2 factors had worst prognosis than high‐risk patients. The 3‐year area under the curve showed that the predictive accuracy of substratification in terms of recurrence and progression were superior to that of non‐substratification (0.685 vs 0.622 and 0.666 vs 0.599, respectively). Additionally, calibration curves showed perfect agreement between the predicted and the actual recurrence and progression. Conclusions Substratification of highest‐risk enables us to further optimize the surgical decisions‐making. Highest‐risk patients with one factor show the similar outcomes as high‐risk patients and deserve to try bladder‐sparing treatment, whereas those with ≥2 risk factors were strongly recommended to undergo radical cystectomy.