Associations between interventions for urolithiasis and urinary tract cancer among patients in Taiwan: The effect of early intervention

The aim of this study was to investigate cancer risk in patients with a history of urolithiasis and to determine whether intervention for calculi attenuated the risk of subsequent urinary tract cancer (UTC). Using data from the National Health Insurance Research Database in Taiwan, we performed a nationwide cohort study enrolling participants (n = 42,732) aged > 30 years who were diagnosed with urinary tract calculi between 2000 and 2009. Age- and gender-matched insured individuals (n = 213,660) found in the health service records over the same period were recruited as the control group. The Cox proportional hazards model and competing risks regression model were used to examine the relationship between urolithiasis and UTC, as well as whether early intervention for urolithiasis decreased the subsequent cancer risk relative to late intervention. Participants with a previous diagnosis of urolithiasis (n = 695) had a 1.82-fold (95% CI: 1.66–1.99, P < 0.001) increased risk of developing UTC. Furthermore, the risk of UTC associated with urolithiasis was higher in women (adjusted HR: 2.43, 95% CI: 1.94–3.05) than in men (adjusted HR: 1.72, 95% CI: 1.55–1.90). When stratified by cancer site, the adjusted HR for bladder, renal pelvis/ureter, renal, and prostate cancers were 1.94 (95% CI: 1.62–2.33), 2.94 (95% CI: 2.24–3.87), 2.94 (95% CI: 2.29–3.77), and 1.45 (95% CI: 1.27–1.65), respectively. Patients who received interventions for urolithiasis within 3 months of detection had a decreased risk of subsequent UTC (adjusted HR: 0.53, 95% CI: 0.40–0.71, P < 0.001). The present study demonstrated that urolithiasis increased the risk of subsequent UTC, especially upper UTC. Hence, it is recommended that physicians administer the appropriate interventions as early as possible upon diagnosis of urolithiasis.