Malignant urachal neoplasms: A population-based study and systematic review of literature

To examine patient and clinicopathological features of malignant urachal neoplasms (MUN) in a population-based cohort, to investigate survival outcomes, and to review the current evidence that exists in the literature.

The Surveillance, Epidemiology, and End Results database was used to identify microscopically confirmed MUN cases diagnosed between 1988 and 2012. Kaplan-Meier analysis was used to determine median and 5-year overall survival (OS) as well as cancer-specific survival (CSS) rates. Cox proportional hazards model was employed to identify variables independently associated with cancer-specific mortality. A systematic literature review was conducted in line with the PRISMA statement.

A total of 420 patients with MUNs were identified. The majority were white (77.6%) and male patients (59%) who presented with low-grade (62.1%), mucinous, noncystic adenocarcinomas (42.9%). From the cohort, 19%, 15.2%, 29.5%, and 30.5% of the patients presented with American Joint Committee on Cancer Stage I to IV disease, respectively. Cancer-directed surgery was performed in 86.5% of the patients. The most common procedure performed was partial cystectomy (52.4%) followed by local tumor excision (20.7%). Median OS was 57 months (95% CI: 41.6-72.4), and median CSS was 105 months (95% CI: 61.5-148.5). Five-year OS and CSS rates were 51% and 57%, respectively. Grade and stage were independently associated with cancer-specific mortality. Mortality rates did not differ between patients who underwent partial cystectomy and radical cystectomy/exenteration (P = 0.165), even after controlling for tumor stage. A total of 16 studies reporting on 585 patients were systematically reviewed, and relevant outcomes were summarized in the Supplemental material.

MUNs are usually low-grade, mucinous, noncystic adenocarcinomas diagnosed at advanced stages. Overall, the prognosis is poor, and high-grade and disease stage are independently associated with cancer-specific mortality.