To obtain a comprehensive dataset on all publications evaluating median overall survival in patients with MUO, a systematic literature search was conducted on the PubMed, Google Scholar, ProQuest and the Cochrane Library from database inception to January, 2024. The following Boolean search string was used in PubMed: (‘malignant ureteral obstruction’ OR ‘malignant ureteric obstruction’ OR ‘MUO’) AND (‘overall survival’ OR ‘survival rate’ OR ‘survival time’). The present study included original articles including case-control, cross-sectional, cohort and randomized control trials discussing the average survival rate in malignant ureteral obstruction patients. The presentation adhered to the PRISMA guidelines (Fig. 1).

The literature search was carried out in English, using specific key words associated with the median survival time in malignant ureteral obstruction patients, with the key words used ‘survival rate’ AND ‘malignant ureteral obstruction’ OR ‘malignant ureteric obstruction’ OR ‘MUO’. These key words were used in different combinations to identify articles in which they appeared in either the title or the abstract. The search was restricted to studies published between 2018 and 2024.

The titles and abstracts retrieved from the databases were reviewed separately by two independent authors. Studies were included if they met the following criteria: i) Original research articles reporting on patients with MUO; ii) adult populations (≥18 years); iii) studies reporting median overall survival and/or survival rates; iv) observational study designs, including cohort and cross-sectional studies; and v) articles published in English.

Studies were excluded if they were reviews, case reports, editorials, conference abstracts, letters, or proceedings; involved pediatric populations; did not report survival outcomes; or lacked accessible full-text data.

Data were collected using a standardized extraction table that recorded the names of the authors, year of publication, study design, study location, the number of participants, type of intervention, and the main outcomes of each study. Articles were identified through key word searches and then screened manually by reviewing the relevance of their titles and abstracts. When eligibility based on inclusion and exclusion criteria was uncertain, the full text was reviewed to confirm suitability, and the relevant information was entered into the extraction table. Survival outcomes were extracted and reported as median overall survival in months, with measures of dispersion (interquartile range or 95% confidence interval) when available. When studies reported survival outcomes using alternative formats or without dispersion measures, the data were presented as originally reported, without transformation. The findings from the included studies were then compared with those reported in other systematic reviews and related literature.

The methodological quality and risk of bias of the included observational studies were assessed using the Newcastle-Ottawa Scale (NOS). This tool evaluates studies across three domains: The selection of study groups, comparability of cohorts and assessment of outcomes. Each study was independently assessed by both authors (RA and HBW), and discrepancies were resolved through discussion. Studies scoring 7-9 points were considered high quality, 4-6 points moderate quality, and ≤3 points low quality.

The systematic search initially identified 219 articles (Fig. 1). After removing duplicates and re-evaluating the records, 113 articles remained. From these, 34 articles were considered potentially relevant. After thoroughly evaluating the complete articles, eight studies fulfilled the eligibility requirements and were incorporated into the final review (7-14). The results of the database search are displayed in Table I and Fig. 1, whereas Table I also presents a summary of the included studies.

Among the eight included articles, seven studies were retrospective studies and one study was a prospective study.

In total, the eight included studies involved 1,691 patients. All of the studies were conducted at single-center institutions. Across the eight included studies, the survival outcomes of patients with MUO were consistently poor, although substantial heterogeneity was observed. Median survival following the diagnosis of MUO or urinary diversion ranged from 3 to 16 months. Studies with larger cohorts, particularly those including patients with advanced-stage gastrointestinal and gynecologic malignancies, generally reported shorter median survival times (7,11-14), whereas selected cohorts with access to subsequent systemic therapy demonstrated relatively prolonged survival (8-10).

Survival appeared to be influenced not only by the method of urinary diversion, but also by patient- and disease-related factors. Several studies reported no statistically significant difference in median survival between ureteral stenting and percutaneous nephrostomy, suggesting that the choice of diversion technique alone does not determine prognosis (8,9,11). Instead, outcomes were closely associated with baseline performance status, nutritional markers (such as serum albumin), renal function, and the feasibility of further oncologic treatment following decompression.

The administration of systemic chemotherapy following urinary diversion emerged as a consistent factor associated with improved survival. By contrast, patients who underwent urinary diversion without subsequent anticancer therapy experienced markedly shorter survival, in some cases limited to only a few months (8). Additionally, studies evaluating advanced disease stages or patients with bilateral obstruction reported worse survival compared with those with unilateral involvement (11,13,14).

Based on the NOS, the overall methodological quality of the included studies was moderate to high (Table II). The majority of studies demonstrated an adequate selection of study populations and clear outcome assessment. Comparability between study groups was the most common source of potential bias, largely due to limited adjustment for confounding variables. No study was classified as low quality.

Felice et al (7) reported that 8.7% of patients had succumbed, while 76.5% were presumed dead. The median interval between the diagnosis of MUO and death was 141 days (IQR, 37.5-442.5). Additionally, 17.4% of patients either succumbed during their initial hospitalization or were directly transferred to the hospital at that time. Artiles Medina et al (8) emphasized that overall survival was influenced by the general health condition of the patient. In their cohort of 188 patients with cancer diagnosed with hydronephrosis, the median overall survival was 6.43 months (IQR, 1.91-14.81 months). The survival rates at 12 and 24 months following diagnosis were 14.8 and 34.1%, respectively. On average, patients were followed for 4.16 months (IQR 0.96-12.93 months). Among 48 of the 188 patients who underwent urinary diversion, the median survival after the procedure was 8.67 months (IQR, 2.99-17.28 months). Their 12- and 24-month post-diversion survival rates were 38.7 and 13.4%, respectively (8).

The most extensive investigation on urinary diversion was carried out by Heo et al (11) and included 778 participants. After undergoing diversion, the median overall survival was reported as 5 months (IQR, 2-12 months), and 91% of the patients (708 individuals) succumbed during the observation period. Patients who received no additional therapy had a notably shorter survival, with a median of only 2 months (IQR, 1-5 months). Conversely, those treated with chemotherapy following urinary diversion exhibited a marked survival benefit, reaching a median of 9 months (IQR, 4-16 months), a difference that was statistically significant (P<0.001) (11).

Following up on a group of patients with MUO, Lapitan and Buckley (22) evaluated the results of two groups: Those who had decompression and those who did not. There appears to be an initial survival advantage, with 38% of those who had decompression against 28% of those who did not survive at 6 months. Nonetheless, the 12-month survival rates of both groups were 16%. According to the available treatment choices, patients were separated into two groups; the group without treatment options had a 12-month survival rate of 0% and a median survival of 38 days (22).

A previous review of prognostic models indicated that patients with no more than one risk factor generally achieved improved outcomes, exhibiting a median survival of ~9-13 months and a 12-month survival rate ranging from 20 to 78% (23). Individuals categorized with ‘intermediate’ risk factors experienced shorter survival, with a median ranging from 5.77 to 8.2 months. By contrast, those with two or more risk factors had the poorest prognosis, with median survival reduced to 1.7-2.6 months and a 12-month survival rate between 0 and 12% (23). In a systematic review of 63 studies, Prentice et al (23) evaluated survival outcomes, quality of life, and the clinical challenges associated with MUO. Their findings revealed that only 23% of patients remained alive at 1 year following diagnosis, with an overall median survival of 6.4 months (23).

Dhani et al (9) further strengthened the evidence by categorizing patients into different risk groups and analyzing outcomes according to the treatment approach. Their findings revealed no significant difference in median survival rates between patients treated with ureteral stents (11.0 months; 95% CI, 8.45-13.56) and those who underwent percutaneous nephrostomy (15.0 months; 95% CI, 13.01-16.98) (P=0.749). A similar trend was observed in stage 3B disease, where survival was 11.0 months for stent placement (95% CI, 8.47-13.53) and 16.0 months for nephrostomy (95% CI, 13.07-18.92), with no statistically meaningful difference (P=0.589). In advanced disease (stages 4A and 4B), both procedures resulted in comparable outcomes, with a median survival of 13.0 months for nephrostomy (95% CI, 10.22-15.77) and 13.0 months for stent insertion (95% CI, 4.27-21.75). When examining survival rates, 6-month survival was 71% for patients with stents and 82% for those with nephrostomy. At 12 months, survival favored nephrostomy (70%) over stents (46%). By 18 months, however, survival rates became nearly identical; 25% in the stent group and 23% in the nephrostomy group (9).

Another study compared the performance of metallic and polymeric stents (12). The median survival duration for the 92 patients was 258 days, and only 19 patients (20.7%) made it to the year mark. Therefore, the treatment of MUO in this clinical group would benefit from the increased patency rate offered by metallic stents, which are expected to have an indwelling length of 1 year (12).

The consistently short survival observed across studies confirms that MUO represents a late manifestation of systemic disease rather than an isolated urological problem. Although reported median survival times ranged from 3 to 16 months, this variation appears to reflect differences in patient selection, underlying malignancy, and the availability of subsequent oncologic treatment rather than the effectiveness of urinary diversion alone. Notably, even studies reporting relatively longer survival involved highly selected patients with preserved performance status and access to chemotherapy, underscoring that the prognosis of patients with MUO is largely driven by the underlying cancer biology.

Notably, survival rates declined sharply within the first year following the diagnosis of MUO, with the majority of studies (22-25) reporting 12-month survival <25%. This finding suggests that MUO may serve as a clinical inflection point, marking transition to end-stage disease in many patients. From a clinical perspective, these survival data emphasize that prolongation of life following MUO is modest and often limited, reinforcing the need for realistic goal setting and early palliative discussions.

Across the included studies, no consistent survival advantage was observed between ureteral stenting and percutaneous nephrostomy (7,8,11,22). While urinary diversion can temporarily restore renal function and allow the continuation of systemic therapy, the absence of clear survival differences suggests that diversion should be viewed as a supportive rather than curative intervention. The benefit of decompression appears to be indirect, primarily enabling chemotherapy or symptom relief, rather than extending survival by itself. While ureteral stenting is frequently considered more comfortable, existing evidence does not conclusively show superior quality-of-life outcomes compared with percutaneous nephrostomy, and findings remain heterogeneous.

Of note, patients who underwent urinary diversion without subsequent anticancer treatment experienced particularly poor outcomes, with survival often limited to weeks or a few months. This observation highlights that urinary diversion in isolation may offer limited value in patients with no remaining oncologic treatment options. Therefore, the decision to decompress should not be routine, but instead carefully individualized, taking into account the likelihood that diversion will meaningfully alter the disease trajectory of the patient.

Lapitan and Buckley (22) reported that several clinical parameters were strongly linked to unfavorable outcomes in patients with MUO. These factors included reduced serum albumin levels, limited therapeutic options, recurrent cancer-related complications, such as pleural effusion, ascites, or distant metastases, electrolyte disturbances such as hyponatremia, the presence of metastatic spread, and an Eastern Cooperative Oncology Group (ECOG) performance status of ≥2(22). In line with these findings, Artiles Medina et al (8) emphasized that severe hypoalbuminemia, hyponatremia, extensive cancer-related events and poor functional performance on the ECOG scale were major determinants of survival.

In addition, Heo et al (11) reported several factors associated with a shorter survival. These included the male sex, a history of receiving chemotherapy without radiotherapy, the progression of malignant complications, a reduced baseline kidney function (estimated glomerular filtration rate, <60 ml/min/1.73 m²), low hemoglobin levels (<10 g/dl), decreased serum albumin levels (<3 g/dl), and the lack of further chemotherapy following the diagnosis of obstruction. They also observed that patients who developed MUO following chemotherapy generally had worse outcomes, indicating that the disease progressed rapidly despite previous systemic treatment (11).

Pradhan et al (24) investigated the impact of hydronephrosis laterality on survival among patients with advanced-stage cervical cancer. The results of their study revealed that those with bilateral hydronephrosis had a significantly shorter survival than those with unilateral involvement. Furthermore, hydronephrosis itself, regardless of whether it was unilateral or bilateral, was found to negatively influence patient outcomes. Age also played a crucial role: Patients aged >60 years of age at the time of diagnosis generally experienced a poorer survival, likely due to disparities in treatment access and the tendency toward under-treatment in elderly populations (24).

Gynecological, urological and gastrointestinal cancers represent the most frequent primary tumor origins leading to MUO. Among urological malignancies, prostate cancer stands out as the predominant cause. This pattern was reaffirmed by the findings in the recent study Felice et al (7), who reported that gynecological cancers accounted for 41.7% of MUO cases, followed by urological (19.1%), gastrointestinal (19.1%), lymphomas (11.3%), and other less common malignancies (8.7%).

The detailed breakdown by Artiles Medina et al (8) further illustrates the diversity of primary tumors causing MUO. Their study identified prostate cancer as the most frequent etiology (17.6%), followed by bladder (16.5%), rectal (11.7%), colon (7.4%), cervical and ovarian cancers (each 5.9%), gastric (5.3%), upper urinary tract tumors (5.3%), endometrial (4.3%), sarcoma and testicular cancers (each 3.2%), lymphoma (2.7%), malignancies of unknown origin (2.7%), pancreatic (2.1%), breast (2.1%), lung (1.6%), kidney (1.6%), and a variety of other rare cancers (1.1%) (8).

In terms of treatment outcomes, Carmona et al (10) investigated how the type of primary cancer influences the failure rates of temporary ureteral stenting. Their findings revealed that stent failure occurred in 41.4% of patients with gynecologic cancers, 38.6% with gastrointestinal cancers, 19% with genitourinary tumors, and 11% with hematological malignancies. Notably, the overall distribution of tumor origins did not exhibit a significant difference between patients with failed stents and those with successful placements (P=0.137) (10).

Taken together, the findings suggest that the management of MUO should prioritize patient-centered outcomes rather than survival alone. Factors such as performance status, nutritional reserve, renal function and patient preferences are critical in determining whether urinary diversion will provide tangible benefit. The heterogeneity in survival outcomes further supports a multidisciplinary approach, in which urologists collaborate closely with oncologists and palliative care teams to align intervention strategies with overall goals of care.

Rather than asking whether urinary diversion prolongs survival, clinicians should consider for whom and under what circumstances diversion is appropriate. In selected patients with good functional status and planned systemic therapy, diversion may serve as a bridge to further treatment. By contrast, for patients with advanced disease, poor performance status, or limited life expectancy, conservative management may better preserve quality of life.

The present systematic review has several limitations that should be acknowledged. First, the majority of the included studies were retrospective and single-center in design, which may introduce selection bias and limit the generalizability of the findings. Second, substantial heterogeneity existed across studies with respect to patient populations, underlying malignancies, diversion strategies and outcome reporting, precluding quantitative synthesis and meta-analysis. Third, survival outcomes were reported using varying formats and levels of detail, and not all studies provided measures of dispersion or adjusted analyses for potential confounders. Finally, decisions regarding urinary diversion are inherently influenced by clinical judgment and patient condition, which may further contribute to unmeasured confounding. These limitations highlight the need for prospective, multicenter studies with standardized outcome reporting to better inform clinical decision-making in malignant ureteral obstruction.

In conclusion, MUO frequently develops as a complication of advanced-stage cancers, particularly those spreading to the pelvic region. The cancers most often linked to MUO include gynecological, urological and gastrointestinal malignancies. Patients with MUO generally have limited survival prospects, with median survival times reported between 3 and 16 months. Furthermore, these patients may spend as much as 30% of their remaining lifespan in hospital care. Considering these circumstances, the role of urologists as part of a multidisciplinary team is crucial for optimizing management approaches and ensuring more patient-centered outcomes.