Urinary calculi and risk of cancer: a nationwide population-based study

Previous studies have shown that urinary calculi are associated with increased risks of urinary tract cancers. However, the association between urinary calculi and overall cancers is a largely undefined body of knowledge. We conducted a nationwide population-based cohort study using Taiwan's National Health Insurance Research Database from 2000 and 2009. Patients were excluded if they had antecedent cancers or urinary calculi before the enrollment. All study subjects were followed until the occurrence of cancer, dropout from the NHI program, death, or the end of 2010. Patterns of cancer incidence in patients with urinary calculi were compared with those of the general population using standardized incidence ratio (SIR). A total of 43,516 patients with urinary calculi were included. After a median follow-up of 5.3 years, 1891 patients developed cancer. The risk of overall cancers was significantly increased (SIR, 1.75; 95% confidence interval [CI], 1.68-1.83). We observed that urinary calculi was associated with higher risk of cancers of kidney (4.24; 95% CI, 3.47-5.13), bladder (3.30; 95% CI, 2.69-4.00), thyroid (2.50; 95% CI, 1.78-3.40), hematologic origin (2.41; 95% CI, 1.92-2.99), breast (1.84; 95% CI, 1.54-2.20), lung (1.82; 95% CI, 1.59-2.07), digestive tract (1.69; 95% CI, 1.57-1.82), and head and neck (1.54; 95% CI, 1.32-1.79), respectively. Our study shows that urinary calculi are associated with higher risk of systemic cancers in addition to urinary tract cancers. Further study is required to validate this association.