LAUSR

Experts’ summary: Kiss and colleagues explored the association between type of temporary preoperative upper urinary tract (UUT) drainage (ie, ureteric stenting vs percutaneous nephrostomy) because of hydronephrosis and rate of UUT recurrence in a retrospective single-centre cohort of nearly 1000 bladder cancer (BCa) patients treated with radical cystectomy (RC) and followed for median 36 mo. The authors’ hypothesis was that ureteric stenting would favour retrograde spillage of tumour cells from BCa, thus increasing the risk of UUT recurrence. Of the 226 patients presenting with hydronephrosis prior to RC, 114 received UUT drainage—53 with ureteric stenting and 61 with percutaneous nephrostomy. At median postoperative time of 17 mo, 31 patients had UUT recurrence: seven of 53 (13%) in the ureteric stenting, zero of 61 (0%) in the percutaneous nephrostomy, and 24 of 891 (3%) in the no drainage group. Of note, all recurrences in the ureteric stenting group were detected in the ipsilateral UUT. On multivariable analysis adjusting for clinical variables (including age, BCa stage, and previous intravesical instillations), ureteric stenting, but neither percutaneous nephrostomy nor hydronephrosis, and previous intravesical instillations were independent risk factors for UUT recurrence. 1. Since the group of patients receiving percutaneous nephrostomy had lower survival compared with their counterparts in the stenting group due to more advanced disease and a sicker comorbidity profile, a competing risk analysis with landmark time analysis should have been run to estimate the cumulative incidence of UUT recurrence and determine whether the risk of UUT recurrence changes over time after RC in a different manner in the two groups [3]. 2. Established risk factors for UUT recurrence, such as BCa multifocality, direct tumour involvement of the ureteric orifice, concomitant invasion of the prostatic urethra, and a history of UUT tumour, remain unreported. It might well be that patients in the stenting group had a higher risk for UUT recurrence already at the time of RC because of a higher prevalence of these factors. 3. It remains unknown whether (and how many) patients in the three groups had had retrograde UUT manipulations in their previous course of the disease, since it emerges that a fair proportion of them underwent RC after multiple treatments for recurrent non–muscle-invasive BCa. 4. It is impossible to ascertain whether the so-called UUT recurrence was generated by a retrograde tumour cell implantation or was indeed a second primary UUT tumour. Since preoperative UUT evaluation with standard imaging, as done in this study, may miss cancer, it might well be that more patients in the stenting group E U R O P E A N U R O L O G Y X X X ( 2 0 18 ) X X X – X X X