Renal Decompression for Malignant Ureteric Obstruction: A Tertiary Hospital Cohort Analysis

Metal Ureteral Stent for Benign and Malignant Ureteral Obstruction

Analysis of Ureteral Stent Compression Force and its Role in Malignant Obstruction

Emergence of malignant ureteral obstruction (MUO) has been reported as a sign of poor prognosis; however, the distribution of survival time in patients with MUO is considerably wide, and no risk classification score has been constructed. To evaluate whether a novel risk classification score for overall survival that we previously developed, is effective in a large cohort. Investigator-initiated, prospective, multicenter diagnostic/prognostic study was conducted. Patients with MUO were divided into three risk groups based on the score calculated using four prognostic factors (PLaCT: Primary site, Laterality, serum Creatinine level, and Treatment for primary site) at the first visit, and prospective follow-up was performed. Overall survival and ureteral stent failure-free survival of each risk group were compared. In total, 300 patients with 21 different primary sites were enrolled. The numbers of patients in good, intermediate, and poor risk groups were 105, 106, and 89, respectively. Median survival times of patients in good, intermediate, and poor risk groups were 406, 221, and 77 days, respectively (P < 0.0001). In 217 patients with ureteral stenting, median ureteral stent failure-free survival times of good, intermediate, and poor risk groups were 385, 183, and 57 days, respectively (P < 0.0001). Limitations include the limited ethnicity and the extended duration of study enrollment. The novel PLaCT risk classification score could divide MUO patients into three risk groups with distinct survival times and ureteral stent patencies. This score will aid in establishing prognosis and treatment strategy for all physicians engaged in cancer treatment.

Uraemia as a result of malignant ureteric obstruction is a recognised event in those with advanced malignancy, usually of pelvic origin, which, if left untreated, is quickly a terminal event. Palliative decompression of the obstructed urinary system, either by percutaneous nephrostomy (PCN), ureteric stent or a combination of both is a recognised method of improving renal function, with presumed low morbidity. The aims of the study were to assess whether PCN placement in malignant ureteric obstruction provided any additional survival benefit or patient morbidity. The case notes of 32 patients with a mean age of 68.1 years (16 male, 16 female) who underwent PCN drainage for malignant ureteric obstruction were retrospectively analysed. Data on the site of primary malignancy, mode of presentation, improvement in renal function, median survival, conversion to internal ureteric stents and intervention-related complications were collected for analysis. The median survival following PCN insertion was 87 days and was unrelated to the patient's age and renal function. Those patients with primary underlying gynaecological malignancies appeared to survive almost 4 times as long as those with underlying primary bladder cancer. Renal function took a mean of 16.8 days to reach a nadir. Almost 79% of patients were able to be discharged from hospital--each patient, however, being re-admitted back to hospital on average 1.6 times prior to their death through PCN or internal ureteric stent related events. Retrospective "useful quality of life" was seen in less than half of the patient cohort. In the presence of malignant ureteric obstruction, palliative percutaneous urinary diversion may be performed and is effective in improving renal function. However, long-term survival is limited and should, therefore, be performed only when the views and wishes of the patient and carers are taken into account and if there is a definitive treatment plan available for the patient as quality of life can be suboptimal.

The Management of Malignant Ureteral Obstruction Treated with Ureteral Stents

Malignant ureteral obstruction is an unfortunate finding that can be caused by a wide-ranging number of malignancies with a prognosis of limited survival. Given its presentation and progression, it can be refractory to treatment by traditional single polymeric ureteral stents. With a higher failure rate than causes of benign ureteral obstruction, a number of other options are available for initial management, as well as in cases of first-line therapy failure, including tandem stents, metallic stents, percutaneous nephrostomies and extra-anatomic stents. We reviewed the literature and carried out a PubMed search including the following keywords and phrases: "malignant ureteral obstruction," "tandem ureteral stents," "metallic ureteral stents," "resonance stent," "metal mesh ureteral stents" and "extra-anatomic stents." The vast majority of studies were small and retrospective, with a large number of studies related to metallic stents. Given the heterogenous patient population and diversity of practice, it is difficult to truly assess the efficacy of each method. As there are no guidelines or major head-to-head prospective trials involving these techniques, it makes practicing up to the specific provider. However, this article attempts to provide a framework with which the urologist who is presented with malignant ureteral obstruction can plan in order to provide the individualized care on a case-by-case basis. What is clear is that prospective, randomized clinical trials are necessary to help bring evidence-based medicine and guidelines for patients with malignant ureteral obstruction.

New Combined Approach in Metallic Ureteral Stenting to Avoid Urothelial Hyperplasia: Study in Swine Model

Introduction: Management of malignant ureteral obstruction (MUO) with ureteral stents remains a clinical challenge, often involving frequent stent exchanges attributable to stent failure or other urological complications. We report our institutional experience with ureteral stents for management of MUO, including analysis of clinical factors associated with stent failure. Methods: We performed a retrospective review of patients treated with indwelling ureteral stents for MUO in nonurothelial malignancies at our tertiary-care institution between 2008 and 2019. Univariate Cox proportional hazards analysis was performed to identify clinical variables associated with stent failure and stent-related complications. Stent failure was defined as need for unplanned stent exchange, placement of percutaneous nephrostomy (PCN), or tandem stents. Results: In our cohort of 78 patients, the median (range) number of stent exchanges was 2 (0-17) during a total stent dwell time of 4.3 (0.1-40.3) months. Thirty-four patients (43.6%) developed a culture-proven urinary tract infection (UTI) during stent dwell time. Thirty-five patients (44.8%) had stent failure. Twenty-two patients (28.2%) underwent unplanned stent exchanges, 23 (29.5%) required PCN after initial stent placement, and 6 (7.7%) required tandem stents. Ten (28.6%) patients with stent failure were treated with upsized stents, which led to resolution in seven patients. Stent failure occurred with 20/44 (45.4%) Percuflex™, 15/27 (55.6%) polyurethane, and 2/3 (66.7%) metal stents. In patients with ≥2 exchanges (N = 45), median time between exchanges was 4.1 (2.0-14.8) months. Bilateral stenting and history of radiation predicted UTI development. Median overall patient survival after initial stent placement was 19.9 months (95% CI 16.5-37.9 months). Conclusions: Ureteral stent failure poses a significant medical burden to patients with MUO. Better methods to minimize stent-related issues and improve patient quality of life are needed. Using a shared decision-making approach, clinicians and patients should consider PCN or tandem stents early in the management of MUO.

BackgroundMalignant ureteral obstruction caused by extrinsic compression of a primary malignant tumour or by metastatic disease is an indicator of poor prognosis with a median life expectancy of about one year. We examined clinical outcomes following Resonance Metallic Ureteral Stent (Cook Medical, Bloomington, IN) placement in patients with malignant ureteral obstruction.MethodsThis was a prospective study of patients with malignant ureteral obstruction who underwent Resonance Metallic Ureteral Stent placement from April 2016 to March 2021. We registered 21 patients (27 collecting systems) with malignant ureteral obstruction and observed them prospectively. The patients first underwent polymer ureteral stent placement followed by replacement with a metallic ureteral stent one month later. Primary outcome was the metallic ureteral stent patency period based on both serum creatinine and the level of hydronephrosis; secondary outcomes were factors affecting patency period and stent-related complications such as symptoms of obstruction (flank pain), bladder irritation, haematuria, and urinary tract infection (presence or absence of fever).ResultsThe study comprised 21 patients (six men, 15 women) with a mean age of 72 years. The median stent patency period in days was not available (NA) (95% CI 210–NA) due to the inability to extract this value from the Kaplan–Meier curve because the event rate did not reach 50%, and the one-year patency rate was 59.2% (95% CI 23.2–82.9). A normal serum creatinine (0.65 to 1.07 mg/dL for men and 0.46 to 0.79 mg/dL for women) one week after polymer ureteral stent placement was a significant factor affecting the long-term metallic ureteral stent patency period. There were no major complications.ConclusionThe Resonance Metallic Ureteral Stent was effective and safe for patients with malignant ureteral obstruction. A normal serum creatinine level one week after placement of a polymer ureteral stent may predict a longer patency period of metallic ureteral stents in patients with malignant ureteral obstruction.

Early Application of Permanent Metallic Mesh Stent in Substitution for Temporary Polymeric Ureteral Stent Reduces Unnecessary Ureteral Procedures in Patients With Malignant Ureteral Obstruction

Malignant ureteral obstruction (MUO) is a common late manifestation of metastatic bladder cancer. We investigated the effectiveness of percutaneous nephrostomy (PN) in our patients with MUO associated with bladder cancer as judged by the serum creatinine concentration in the presence of unilateral or bilateral obstruction and in relation to the treatment results. The records of 23 consecutive patients with a mean age of 55 years (21 men, 2 women) who underwent PN were retrospectively reviewed. Eleven had unilateral obstruction. We assessed normalization of creatinine concentration, survival, and quality of life after PN in patients with either unilateral or bilateral obstruction. The mean serum creatinine concentration before PN was 6 mg/dL (range 2.1-24.6 mg/dL). Percutaneous nephrostomy provided improvement to normal renal function in 19 patients (83%). The mean survival of patients after PN was 4.9 months (range 1-14 months). No independent factor playing a significant prognostic role was determined. The overall complication rate was 30% (7/23), namely kinking or dislodgment of nephrostomy tubes. After PN, all patients were able to undergo treatment for bladder cancer. Percutaneous nephrostomy, with a low morbidity rate, is a safe urinary diversion technique in bladder cancer-induced MUO. It relieves at least the devastating effects of uremia and allows appropriate treatment for the malignancy.

Malignant ureteral obstruction (MUO) has traditionally been a difficult problem to manage. Indwelling ureteral stents have a failure rate up to 50%, necessitating the placement of percutaneous nephrostomy (PCN) drainage, which has associated complications and impacts on quality of life. Recently, metallic ureteral stents have emerged as a treatment for extrinsic ureteral obstruction. We present our initial experience using Resonance (Cook Urologic, Spencer, IN) full-length metallic stents for MUO. 20 patients (27 renal units) with advanced cancers and MUO were treated with metallic stents. Patients were followed prospectively to evaluate for recurrent obstruction. Perioperative morbidity and overall mortality were recorded. The mean patient age was 49.9 years (SD 18.9). The primary malignancies causing MUO were gastrointestinal (8), gynecologic (6), genitourinary (2), or other (4). All but two renal units had been previously treated with traditional stents. Eight out of 20 (40%) patients required further intervention for their MUO. Mean time to failure for the metallic stents was 7.4 months (222 days). Two patients required conversion to percutaneous drainage. Five patients required change to traditional stents (3) or removal of metallic stents. At the last follow-up, sixteen patients had died. Fourteen of the sixteen patients died with functioning metallic stents in place, although one patient who initially had bilateral metallic stent placements had a left stent removed due to migration. Of the remaining four living patients, two have functioning metallic stents at a mean follow-up of 42 months. MUO remains a difficult clinical problem in a group of patients with a high mortality. While metallic stents ultimately have a failure rate similar to that of traditional stents, the mean time to failure is longer. Therefore, metallic stents may benefit patients with MUO, because the longer dwell time may eliminate the need for more frequent stent changes or further interventions.

To determine the potential predictors of antegrade ureteral stenting (AUS) failure in patients with malignant and benign ureteral obstruction. We retrospectively evaluated 116 AUS procedures performed in 80 patients for ureteral obstruction due to malignant and benign causes. Variables such as etiology for obstruction, ureter shape, previous treatment regimen, history of ileal loop diversion, and presence of percutaneous nephrostomy were recorded. Univariate and multivariate logistic regression methods were used between these variables and stent failure. Antegrade ureteral stenting was performed as single stage in 24 procedures (n: 24/116, 21%) and performed as a two-step approach after percutaneous nephrostomy in 92 procedures (n: 92/116, 79%). Ureteral stent was successfully deployed in 112 AUS procedures (n: 112/116, 96.5%). In 35 of these successful procedures, the patients were referred to our department due to prior failed retrograde ureteral stenting (RUS). Subsequent stent failure occurred in 40 procedures after a median interval of 39days. Pre-stenting percutaneous nephrostomy (PN) was a statistically significant risk factor for stent failure (p: 0.041), and age showed an inverse relationship with stent failure (p: 0.008). Complications in early (within the first 30days after procedure) and late stage occurred in a total of 17 procedures. Early complications included urinary tract infection (n: 11), stent migration (n: 3), and malposition (n: 1). Late complications (after 30days) were urinary tract infection (n: 1) and stent migration (n: 1). This study suggests that AUS can be performed effectively in both benign and malignant ureteral obstructions including cases with prior failed RUS. Two-step AUS after percutaneous nephrostomy was found to be a significant risk factor for subsequent stent failure in our study cohort.

Background: Urologists are often referred to manage the extrinsic malignant ureteral obstruction (MUO) caused by nonurological malignancies. Usually palliative urinary diversion (ureteral stent or nephrostomy) will be performed; however, in the cases of no symptom or poor prognosis, observation (OBS) without any intervention will be selected. There are few reports about outcome of the OBS policy for MUO. Objective: To evaluate the outcome of palliative urinary diversion or OBS for MUO. Design: We retrospectively reviewed the selection of treatment and the prognosis. Setting/Subjects: A total of 151 cases were introduced to our department as MUO between April 2011 and December 2016. Measurements: The patients were divided to immediate palliative urinary diversion (immediate-DIV) or OBS. The latter patients were subdivided to OBS followed by deferred palliative urinary diversion (deferred-DIV), and observation only (OBS-only). Results: There was no significant difference between immediate-DIV and OBS about overall survival (OS) from the consultation. In OBS group, deferred-DIV did not prolong prognosis from the consultation more than OBS-only. In the same way, there was no significant difference between immediate-DIV and deferred-DIV in OS from the intervention. Unfavorable prognostic factors for OS were lack of anticancer treatment after consultation, symptoms of MUO, and gastrointestinal cancer. When we classified the patients by these factors, the group with three factors showed significantly poorer prognosis than the others. Conclusion: Immediate-DIV or OBS did not influence the prognosis in the whole patients. Three prognostic factors that will be judged by urologists easily might be useful for the indication and timing of palliative urinary diversion.

BackgroundUrologists frequently encounter malignant ureteral obstruction (MUO) caused by advanced urological or non-urological malignant disease, but the treatment policy is unclear. The present study examined the risk factors for predicting ureteral stent failure in patients with MUO after ureteral stent insertion and the change in the renal function after retrograde ureteral stent insertion in cases of bilateral hydronephrosis.MethodsA total of 39 patients who required ureteral stent placement for MUO at Yokohama City University Medical Center (Yokohama, Japan) between February 2007 and May 2016 were included in this study. The age, gender, type of cancer, hydronephrosis side, pre-stenting estimated glomerular filtration rate (eGFR), and eGFR increase were assessed as predictive factors for stent failure. Among these 39 patients, 25 showed bilateral hydronephrosis. Thirteen of these patients had bilateral ureteral stents placed, and the remaining 12 had a unilateral ureteral stent placed. The renal function and overall survival (OS) were analyzed between these two groups.ResultsAmong all 39 patients, 9 (23.1%) had stent failure. A univariate analysis revealed that causative disease (gastrointestinal cancer vs. others; p = 0.045) and laterality of hydronephrosis (bilateral vs. unilateral; p = 0.05) were associated with stent failure. A multivariate analysis revealed that only age (hazard ratio, 0.938; 95% confidence interval, 0.883–0.996; p = 0.038) was associated with stent failure. A Kaplan-Meier analysis and log-rank test indicated that having a unilateral ureteral stent placed was not correlated with a lower OS rate than having bilateral ureteral stents placed (p = 0.563). Among patients with bilateral hydronephrosis, the increase in the eGFR of those who had bilateral ureteral stents placed was not significantly different from that of those who had a unilateral ureteral stent placed (p = 0.152).ConclusionsWe revealed that age > 60 years was helpful for predicting stent failure. MUO due to gastrointestinal cancer and bilateral hydronephrosis may be predictive of stent failure. These factors may help urologists decide the optimal time to perform early percutaneous nephrostomy. These findings suggest that patients with bilateral hydronephrosis do not necessarily need to have a ureteral stent placed into both sides of the hydronephrosis.