Editorial Comment to "Improving compliance with guidelines may lead to favorable clinical outcomes for patients with non-muscle-invasive bladder cancer: A retrospective multicenter study".

In the present study, Sato et al.1 focused on the important topic of whether guideline-recommended therapy affects the oncological outcome of non-muscle-invasive bladder cancer (NMIBC) using 1204 patients collected from 10 institutions. They found that, surprisingly, 74% of their high-risk patients did not receive maintenance BCG therapy. Moreover, propensity score-matched analysis of T1 NMIBC patients who received a second TUR as well as maintenance BCG therapy revealed that they had a favorable recurrence-free survival (RFS). One of the concerns about the study is that the definition of maintenance BCG therapy was ambiguous. The authors defined maintenance BCG therapy as patients who received additional BCG instillation following induction BCG. Although the strict schedule of maintenance BCG instillation has not yet been established in Japan, Hinotsu et al.2 reported that 18-month BCG maintenance therapy contributed to significant prolongation of RFS compared to BCG induction therapy in patients with recurrent or multiple NMIBC. The Japanese Urological Association guidelines state that the regime of BCG maintenance should be based on the SWOG 85073 trial for at least 12 months. Thus, further studies are warranted to clarify the importance of guideline adherence using the BCG maintenance schedule reported by SWOG 8507 or Hinotsu et al. Some part of initial T1 disease, so-called very high-risk tumor, needs to be treated with radical cystectomy (RC) when additional risk factors, such as concomitant non-UC subtype, presence of lymphovascular invasion, and concurrent carcinoma in situ in either bladder or prostatic urethra, are included. However, the compliance of RC in very high-risk NMIBC patients is low. We previously reported4 the importance of performing RC during the time course of NMIBC stage in accordance with the guidelines' recommendation. In this report, when NMIBC patients who followed the guidelines from initial transurethral resection of bladder tumors to RC were defined as a guideline-adherent group, guideline non-adherence was independently associated with cancer-specific death. The importance of guideline-adherent therapy in T1 disease, including RC for very high-risk tumor, needs to be clarified in a future study. Eiji Kikuchi: Conceptualization; Writing—review and editing. Nozomi Hayakawa: Writing—original draft and editing. Eiji Kikuchi received honoraria for lectures from MSD K.K. and Astellas Pharma Inc.