This issue contains one Guideline, one Review Article, 12 Original Articles and two Urological Notes.

The Committee for the Development of Guidelines for Infection Control in the Urological Field, including Urinary Tract Management of the Japanese Urological Association, together with its systematic review team and external reviewers, have prepared a set of practice guidelines. Takahashi et al. (Sapporo, Japan) created an abridged version of those guidelines as Guidelines for Infection Control in the Urological Field, including Urinary Tract Management (revised second edition). This revised edition, along with topics from the first edition, includes information on hepatitis B virus reactivation and urinary catheter management in home care, which consists of 12 topics and 53 clinical questions. It also covers new sections comprising details for not only urologists, but also healthcare professionals involved in urinary tract management.

Although narrow band imaging (NBI) has been previously shown to improve detection of lesions over white light, it is unclear that NBI reduces recurrence rates in patients undergoing transurethral resection of a bladder tumor (TURBT) compared with conventional white light TURBT. In this Review Article, Gravestock et al. (Newcastle, UK) assessed the effect of NBI-guided TURBT compared with white light on recurrence rates in non-muscle-invasive bladder cancer. According to the diagram outlining study selection based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses, three randomized controlled trials were included in this review article. In contrast to previous reviews, no statistically significant result was obtained, although a trend in favor of NBI was shown. Currently, the benefit of the use of NBI during TURBT remains unclear, and further well-designed clinical trials are warranted.

Two Original Articles on robot-assisted partial nephrectomy (RAPN) are included in this issue. Yokoyama et al. (Tokyo, Japan) carried out the nationwide retrospective study to evaluate the trends and safety of RAPN during the initial 2-year period after Japanese government approval for this type of procedure in April 2016. During this period, the number of RAPNs and the number of institutions in which the surgery was carried out steadily increased, resulting in 3722 cases receiving this surgery. This study found that the surgical outcomes of RAPN were practically equivalent between lower- and higher-volume institutions. In conclusion, RAPN was associated with an acceptable safety profile and good surgical outcomes, regardless of the institutional caseloads.

Based on the theory that renal ischemia, warm in particular, contributes to renal function loss, there has been debate on the maximum tolerable warm ischemic time. Ishiyama et al. (Tokyo, Japan) carried out the retrospective multi-institutional study to evaluate the association between warm ischemic time and postoperative renal function. This study included 1131 patients, which were classified into shorter (<30 min; n = 1038) and longer (≥30 min; n = 92) groups based on the ischemic time required. In conclusion, when matched for baseline characteristics, warm ischemic time ≥30 min, which was required in large and more complex tumors, did not result in inferior short- and mid-/long-term outcomes in RAPN.

Pembrolizumab has been shown to improve overall survival (OS) in patients with advanced or metastatic urothelial carcinoma that is resistant to platinum-based chemotherapy. The optimal number of cycles of chemotherapy, however, has not yet been determined when considering the effect on the efficacy of subsequent pembrolizumab or OS. Kato et al. (Osaka, Japan) carried out a multicenter, retrospective study to determine the impact of the objective response to and number of cycles of chemotherapy on OS. In conclusion, the authors found that the best response to and the number of cycles of platinum-based chemotherapy were not independent prognostic factors of OS, indicating that the therapeutic benefit of pembrolizumab can be expected irrespective of the best response to and number of cycles of chemotherapy.