Presentation and survival for urachal cancer: Findings from a nationwide multicenter cohort study in Norway

Abstract

Background and objective: This study aims to map the prevalence and treatment of urachal cancer (UrC) in Norway, establish survival rates, identify prognostic factors, and evaluate whether any of the three commonly used staging systems for UrC provide superior prognostic value.

Methods: In this retrospective cohort study, data from the National Cancer Register was collected to identify patients diagnosed with UrC between1997 and2022. Eligible cases (n = 43) underwent retrospective review of their individual hospital records. All patients were staged using the Sheldon, Mayo, and Limonnik-revised TNM systems. This was performed locally and then checked by the coordinating center.Key findings and limitations:The median age at surgery was 59.5 years (IQR 49-73), with 57% of patients being male. The median follow-up time for survivors was 98 months (IQR 81-153). Macroscopic hematuria was the most common presentation (67%, n = 28). Recurrence-free survival (RFS) rates at 1, 3, and 5 years were 71%, 57%, and 53%, respectively. Cancer specific survival (CSS) was 95%, 62%, 55%, and overall survival (OS) rates were 93%, 61%, 46% at the same time points. Smaller tumor size was an independent predictor of improved CSS (HR 1.3, CI: 1.01-1.6, p = 0.045). Of the three staging systems, only the Mayo system showed statistically significant differences between stages for OS, while none of the systems, including Mayo, showed significant differences for CSS. Study limitations include a small sample size and a prolonged study period of 25 years, which may affect the generalizability of the findings and introduce bias due to changes in clinical practice over time, such as advancements in surgical techniques, and oncological therapies.

Conclusions and clinical implications: Urachal cancer is frequently diagnosed at an advanced stage. Our findings suggest that the Mayo system more effectively distinguishes between localized, locally advanced, and advanced disease compared to the Sheldon and Limonnik-revised TNM systems.

Keywords: Urachal cancer; bladder cancer; survival; urachus.

Figure 1.

Kaplan–Meier estimates with 95% confidence intervals for (a) 5-year recurrence-free survival, (b) 5-year cancer-specific survival, and (c) 5-year overall survival following treatment for urachal cancer in Norway. The number of patients at risk is shown in the table beneath each respective panel.

Figure 2.

Overall survival and cancer-specific survival estimates up to 5 years after treatment based on the following staging systems: (a and b) Mayo, (c and d) Sheldon, and (e and f) Limonnik’s TNM. The tables below each curve display the number of patients at risk at specific time points. OS: overall survival; CSS: cancer-specific survival; L: localized disease; LA: locally advanced disease; A: advanced disease.