Treatment outcomes of ureteral stenting for malignant extrinsic ureteral obstruction: a comparison between polymeric and metallic stents.

Purpose: To compare treatment outcomes, more specifically patency rate, of polymeric and metallic stents for malignant ureteral obstruction.

Patients and methods: Between August 2007 and September 2017, we retrospectively analyzed the data of 92 patients (126 ureters) having a diagnosis of malignant extrinsic ureteral obstruction treated with indwelling ureteral stents (polymeric and full-length metallic stents). Of these patients, 35 (54 ureters) were treated with polymeric stents and 57 (72 ureters) with a Resonance® metallic stent. The observation period was censored to 1 year. Survival rate in cases of malignant ureteral obstruction was calculated, and the relationship between the causes of ureteral obstruction, the stent type, and the patency rate was evaluated.

Results: The median observation period was 145 days, with a median survival time of 258 days. The stent patency rate was 70.9% at 1 year, regardless of stent type. Stent occlusion was observed in 20 patients (33 ureters). According to stent type, occlusion of the polymeric and metallic stents was identified in 12 (22%) and 8 (11%) cases, respectively. The clinical features associated with stent failure were assessed. In univariate analysis, the patency rate was significantly better for the metallic stent than for the polymeric stent (1-year patency rate; 78.4%, 61.1%, respectively, HR, 2.15; 95% CI, 1.07-4.33; p =0.031). However, the patency rate among patients with abdominal dissemination, lymph node metastasis, and direct compression by tumor was not significantly different.

Conclusion: Indwelling ureteral stents, particularly metallic stents, are effective for the treatment of malignant ureteral obstruction.