Stent Failure in Ureteral Obstruction: Are You at Risk?
"A new risk stratification model helps predict ureteral stent failure, allowing for personalized treatment plans and better patient outcomes."
Malignant extrinsic ureteral obstruction (MUO) occurs when a tumor or growth outside the ureter (the tube that carries urine from the kidney to the bladder) presses on it, blocking the flow of urine. This can lead to serious complications, including kidney damage and even death. Ureteral stents are frequently used to open up the blockage, providing relief and maintaining kidney function. However, these stents can fail, requiring additional procedures and impacting a patient's quality of life. If untreated, ureteral obstruction can lead to renal failure and even death [4]. However, there is evidence that palliative urinary diversion prevents the deterioration of renal failure and may result in improved survival [5].
The challenge lies in predicting which patients are most likely to experience stent failure. Recognizing risk factors early on allows doctors to make more informed decisions about initial treatment strategies, potentially avoiding unnecessary procedures and improving patient outcomes. Current methods of managing MUO often involve ureteral internal stents, percutaneous nephrostomy (PCN) catheters, or extra-anatomic stents in order to provide symptomatic relief and maintain renal function.
A recent study published in the International Journal of Clinical Oncology has shed light on this critical issue, identifying key factors that predict ureteral stent failure in patients with MUO. This article breaks down the study's findings, explaining a new risk stratification model that can help doctors better manage this challenging condition. We will also provide a detailed explanation about the article and its data points for the audience.
Measured Burden of Stent Failure
Studies have examined stent failure-free survival and predictors of failure in malignant ureteral obstruction. One retrospective study reviewed 71 patients treated with cystoscopic retrograde ureteral stent insertion, while another analyzed 91 patients with radiologically significant hydronephrosis and 132 stented ureters. Malignant ureteral obstruction is also described as an unfavorable sign commonly seen in patients with advanced, incurable cancer.
From Catheters to Modern Diversion
Ureteric stents are described as fundamental to modern urological practice, with their development traced over the last century. Early devices were ureteric catheters exteriorized outside the body and were associated with migration, infection, and encrustation. In malignant obstruction, stenting developed as a way to bypass obstruction, relieve symptoms, and potentially prolong survival, although frequent exchanges remain a challenge because of stent failure and other complications.
What Predicts Stent Failure? Key Risk Factors Identified
The study, led by Hiroshi Matsuura and colleagues, retrospectively analyzed data from 91 patients who underwent ureteral stent placement for MUO. The researchers looked at various clinical and radiological factors to determine which ones were associated with stent failure. Stent failure was defined as the necessity for another alternative form of urinary diversion (including PCN or an external ureteral stent) for one of the following reasons: an inability to replace the ureteral stent; increasing serum creatinine levels; complication by obstructive pyelonephritis; or the presence of a recurrent stent obstruction.
- Bladder Invasion: When the cancer has spread to involve the bladder.
- Severe Hydronephrosis: Significant swelling of the kidney due to the backup of urine before stent insertion. The severity of hydronephrosis was evaluated by US according to the grading system of the Society for Fetal Urology.
Metallic Stents and Failure Predictors
A 2026 meta-analysis concluded that metallic ureteral stents had higher success rates than polymer stents in malignant ureteral obstruction, particularly with longer follow-up, but also carried an increased risk of complications. A review of advances in stents identifies male sex, age, hydronephrosis severity, serum creatinine, tumor type, local tumor invasion, and stent diameter among commonly reported risk factors for failure. A separate 2026 systematic review used comparative studies identified through PubMed, MEDLINE, Embase, Web of Science, Cochrane CENTRAL, and Scopus through May 31, 2025.
Failure Is Not Always Predictable
One study reported that no pre-stent factor was significantly associated with stent failure. The same report found no difference in outcomes between patients who required a metal stent for malignant versus benign ureteral obstruction. These findings challenge the assumption that routinely available pre-stent characteristics can reliably identify every patient at risk of failure.
Comparing Stent Strategies
A 2026 study compared metallic and polymeric stents in 148 patients involving 240 ureters with malignant ureteral obstruction; the patients underwent stent placement between December 2014 and April 2022. Another report notes that stents for malignant obstruction have had failure rates as high as 40%, while metallic long-term stents have been studied as an alternative despite high cost and patient discomfort. A separate comparison evaluated a non-metallic long-term stent in malignant and non-malignant ureteral obstruction, highlighting that device selection also needs to account for the underlying cause of obstruction.
Empowering Patients and Optimizing Care
This study provides valuable insights for managing patients with malignant extrinsic ureteral obstruction. By identifying those at high risk of stent failure, clinicians can make informed decisions about initial treatment strategies, potentially improving patient outcomes and quality of life. The findings also highlight the importance of shared decision-making, ensuring that patients are fully informed about the risks and benefits of different treatment options.
Risk Stratification Remains Central
The optimal management of malignant extrinsic ureteral obstruction remains unclear, according to the cited clinical outcomes research. That work assessed prognosis after ureteral stenting and examined predictive factors for overall survival with the aim of creating a risk-stratification model. The broader evidence therefore supports individualized decisions about renal-pelvis drainage rather than assuming that one stent strategy is appropriate for every patient.
Reducing Exchanges and Complications
Future progress will need to address the continuing clinical challenge of managing malignant ureteral obstruction with ureteral stents. The cited institutional study specifically analyzed clinical factors associated with stent failure. Its focus reflects an ongoing need to identify patients who may require closer monitoring, alternative drainage strategies, or adjustments to exchange planning.