Tumor Stent for Chronic Ureteral Obstruction: Which Are Predictors of Stent Failure?

Purpose: To identify predictors of UROSOFT® tumor stent failure. According to the manufacturer, this reinforced ureteral stent has a maximal dwell time of 6 months. Nonetheless, stent failure may reduce this maximal dwell time. Methods: All patients undergoing first-time UROSOFT tumor stent insertion in our institution between 2010 and 2018 were considered for this retrospective analysis. Primary endpoint was stent failure and defined as premature stent exchange or percutaneous nephrostomy insertion. The local ethics committee approved the study protocol (study ID: BASEC 2020-00175). Results: In total, 182 patients were available for analysis. Median age was 68 years. Causes for tumor stent placement were extrinsic ureteral obstruction in 144 patients (79%) and intrinsic obstruction in 38 patients (21%). Tumor stent failure-free survival estimates at 1, 2, 3, 4, and 5 months were 89%, 83%, 76%, 65%, and 52%, respectively. Patients with stent failure had significantly higher grade of hydronephrosis, higher urinary culture bacterial growth, higher serum white blood cell count, higher C-reactive protein, and lower estimated glomerular filtration rate at the time of reintervention, compared with patients who underwent regular stent exchange. Of all baseline and perioperative parameters, we found bilateral insertion, intrinsic ureteral obstruction, and urinary tract infection (UTI) at time of tumor stent insertion to be significant and independent predictors of stent failure (all p < 0.05). Conclusion: Despite a theoretical maximal dwell time of 6 months, ∼50% of all cases are subject to premature stent failure. Predictors of stent failure are bilateral insertion, intrinsic ureteral obstruction, and UTI at the time of tumor stent insertion. Preoperative antibiotic therapy may impact on stent failure rate.