Editorial Comment on Validation of the risk stratification newly defined in the Japanese Urological Association guidelines 2019 for non-muscle invasive bladder cancer: A multi-institutional collaborative study.

Abstract

In 2019, the Japanese clinical practice guidelines for bladder cancer were revised for the first time in 4 years (the Japanese Urological Association [JUA] guidelines 2019). In the NMIBC section, the highest-risk group is newly classified, and non-muscle invasive bladder cancer (NMIBC) is stratified into four groups: low-, intermediate-, high-, and highest-risk groups.1, 2 Miyamoto et al. performed a multicenter retrospective analysis in NMIBC patients, and demonstrated that the JUA guidelines 2019 could stratify recurrence-free survival (RFS), progression-free survival (PFS), cancer specific survival (CSS) and overall survival (OS) by dividing patients into 4 risk groups.3 This study emphasizes the usefulness of this risk stratification for decision-making in clinical practice. Furthermore, the authors raise an issue with heterogeneity in the intermediate-risk group, because some of these patients had the highest risk of recurrence. The scoring system they proposed could clearly divide RFS between favorable and unfavorable intermediate risk groups. Generally, sub-classification is introduced since it can predict the prognosis more accurately. Meanwhile, we must be careful not to make the predictive tool unnecessarily complicated because it should be applied in clinical practice. We should look at the NMIBC scoring system in the European Association of Urology guidelines.4 It was able to predict RFS and PFS more precisely than conventional risk stratifications, but now almost nobody applies it in daily clinical practice because it requires a time-consuming process. I totally agree that the intermediate-risk group includes some cases with an unusual clinical course. Although they rarely progress, they recur more frequently and experience more tumors than the high-risk cases. Extracting them from intermediate-risk group is clinically very important, because these patients may require a specific treatment strategy, including intravesical instillation, aminolevulinic acid (ALA), immune checkpoint inhibitor (ICI), etc. I hope that a “simple and practical” sub-classification system for the intermediate-risk group can be added to the next JUA guidelines. None declared.