Impact of diagnostic ureteral catheterization on intravesical tumour recurrence following radical nephroureterectomy for upper tract urothelial carcinoma

Purpose To investigate whether even a minimally invasive diagnostic procedure for the upper tract such as ureteral catheterization (UCath) may substantially increase the risk of intravesical recurrence (IVR) in patients with upper tract urothelial carcinoma (UTUC) treated with radical nephroureterectomy (RNU). Methods The present, retrospective study enrolled 163 patients undergoing RNU for UTUC between 2010 and 2021 at two, tertiary care hospitals. The primary endpoint was the association between UCath and IVR-free survival (IVRFS). The secondary endpoints were the association of ureterorenoscopy (URS) and URS biopsy (URSBx) with IVRFS. Directed acyclic graph (DAG)-guided multivariable models were used to adjust for potential confounders. Results Of the 163 patients, 128 (79%), 88 (54%), and 67 (41%) received UCath, URS, and URSBx, respectively. URS was performed concurrently with UCath. During the follow-up period (median: 47 months), IVR developed in 62 patients (5-year IVRFS rate: 52%). A DAG included concurrent bladder cancer, tumour size, hydronephrosis, positive cytology, and multiple UTUCs as potential confounders of the association between UCath and IVR. Both DAG-guided and stepwise multivariable models revealed a significant association between UCath and IVR (hazard ratio: 17.8; P < 0.001). UCath was also associated with shorter IVRFS in a subset of 75 patients who had not received URS ( P < 0.001). In contrast, URS and URSBx were not associated with IVR in patients who had received UCath and URS, respectively. Conclusion Any diagnostic manipulations of the upper urinary tract, even a minimally invasive procedure like UCath, could confer a risk of post-RNU IVR in UTUC patients.