Risk and Prognosis of Cancer in Patients with Obstructive Uropathy Compared with the General Danish Population

To examine whether obstructive uropathy is associated with increased risk of cancer and whether mortality differs between patients with cancer with and without obstructive uropathy.

In a nationwide population-based Danish cohort study including 37,275 adult patients with a first-time hospital-related diagnosis of obstructive uropathy in 1996 to 2022, we assessed cumulative cancer incidence (risk) and standardized incidence ratios (SIR). Furthermore, we compared the mortality of 7,485 patients diagnosed with cancer after obstructive uropathy diagnosis with that of 69,785 patients with cancer without obstructive uropathy matched by age, sex, cancer site, stage, and calendar year of cancer diagnosis.

The 3-month risk of cancer after an obstructive uropathy diagnosis was 9.6%. The 3-month SIR was 34.2 [95% confidence interval (CI), 33.1-35.4] while the 1 to <5 year SIR was 1.2 (95% CI, 1.1-1.3). The 3-month SIRs were 82.7 (95% CI, 79.3-86.2) for urological cancer, 88.8 (95% CI, 79.8-98.5) for gynecological cancer, and 13.9 (95% CI, 12.0-15.9) for colorectal cancer. After 1 year of follow-up, the excess number of urological cancers decreased to 0.1 per 100 person-years, whereas we observed no excess risk of gynecological and colorectal cancers. The 5-year all-cause mortality following cancer was 64.1% (95% CI, 62.9-65.2) in patients with an obstructive uropathy diagnosis before cancer diagnosis and 53.2% (95% CI, 52.9-53.6) in those without.

A first-time diagnosis of obstructive uropathy can be a clinical marker of underlying undiagnosed cancer and elevated mortality in relation to any cancer diagnosed after obstructive uropathy.

These findings can inform the follow-up recommendations for obstructive uropathy.