Cross-sectional analysis of indwelling ureteral stents in patients with malignant ureteral obstruction

Purpose: Malignant ureteral obstruction (MUO) leads to renal failure, pain, and reduced quality of life. Ureteral stent insertion is common but has high occlusion rates. The PLaCT classification, published in 2021, predicts MUO risk. This study evaluated the luminal patency of nonmetallic and metallic stents in MUO patients using the PLaCT classification to establish appropriate treatment protocols. Materials and methods: We enrolled 461 stents from 357 patients with MUO between March 2020 and March 2024. Replaced ureteral stents were cut 5 cm from the vesical side and analyzed for luminal obstruction, graded from 1 (0%–20%) to 4 (71%–100%). We evaluated the correlation between PLaCT risk and stent obstruction. Stents were replaced within 6 months or sooner if clinical obstruction occurred. Performance status scores of 3+ or severe stenosis were excluded. Results: We used 235 metal stents (RUSCH Tumor) and 226 nonmetallic stents (Inlay Optima). In the good group, there was no significant occlusion difference between metallic and nonmetallic stents ( P = 0.066). In the intermediate group, nonmetallic stents had higher occlusion rates ( P < 0.001). Most clinical occlusions in nonmetallic stents were grade 1 or 2, accounting for 27 of 30 cases. In the poor group, 30 occlusion cases occurred in 47 ureters with metallic stents and 41 cases in 58 ureters with nonmetallic stents, with no significant difference ( P = 0.324). Metallic stents: 28 cases and nonmetallic stents: 30 cases showed grade 3 or higher luminal obstruction. Conclusions: For MUO, confirming the PLaCT classification is essential. Nonmetallic stents are recommended for the good group, metal stents for the intermediate group, and nephrostomy for the poor group. Appropriate treatment choices based on PLaCT classification can prevent unnecessary surgeries and reduce patient suffering.