Comparison of clinical outcomes between metallic and polymeric ureteral stents in malignant ureteral obstruction: A retrospective comparative study

Background: The present study compared the clinical outcomes and indications of metallic ureteral stents (MS) and polymeric ureteral stents (PS) in patients with malignant ureteral obstruction (MUO). Methods: We analyzed 148 patients (240 ureters) with MUO who underwent ureteral stent placement at our Department of Urology between December 2014 and April 2022. The cohort included 67 patients (112 ureters) who received metallic stents (MS group) and 81 patients (128 ureters) who received polymeric stents (PS group). We evaluated overall survival and the primary underlying malignancies, and compared operative times, ureteral stent patency rates, and factors associated with stent obstruction between the two groups. Results: The one-year overall survival rate of patients with MUO was 27.2%, with a median survival time of 209 days. The main primary malignancies were gynecologic and gastrointestinal cancers, most commonly cervical, gastric, colorectal, breast, and ovarian cancers, in that order. The operative time for stent insertion was significantly longer in the MS group than in the PS group for both bilateral (p=0.0004) and unilateral (p=0.0094) placements. The one-year stent patency rate was significantly higher in the MS group (62.0%) than in the PS group (48.5%) (p=0.0144). Factors associated with stent obstruction included lower ureteral obstruction (p=0.0401), direct tumor compression (p=0.0172), pyuria (p=0.0028), and elevated preoperative serum creatinine (p=0.0088) in the MS group, and peritoneal dissemination (p=0.0005) in the PS group. A comparison of stent patency between the groups according to obstruction factors showed no significant differences for lower ureteral obstruction (p=0.5140), direct tumor compression (p=0.8215), or pyuria (p=0.8401). However, among patients with peritoneal dissemination, the stent patency period was significantly longer in the MS group (p=0.0001). Conclusions: Metallic ureteral stenting, which has higher patency rates than PS, is a safe and effective treatment option for MUO, particularly in the patients with peritoneal dissemination.