RISK OF URINARY-TRACT CANCERS FOLLOWING KIDNEY OR URETER STONES

Background: A relationship has been suggested between kidney or ureter stones and the development of urinary tract cancers, In this study, a population-based cohort of patients hospitalized for kidney or ureter stones in Sweden was followed for up to 25 years to examine subsequen t risks for developing renal cell? renal pelvis/ureter, or bladder can cer, Methods: I)ata from the national Swedish In-patient Register and the national Swedish Cancer Registry were linked to follow 61 144 pati ents who were hospitalized for kidney or ureter stones from 1965 throu gh 1983. Standardized incidence ratios (SIRs) and 95% confidence inter vals (CIs) were computed on the basis of nationwide cancer incidence r ates, after adjustment for age, sex, and calendar year. Results: Risk of renal cell cancer was not elevated in this cohort. Significant exce sses of renal pelvis/ureter cancer (SIR = 2.5; 95% CI = 1.8-3.3) and b ladder cancer (SIR = 1.4; 95% CI 1.3-1.6) were observed, but the SIRs for women were more than twice those for men. Risks varied little by a ge or duration of follow-up. Risks of renal pelvis/ureter cancer and b ladder cancer among patients with an associated diagnosis of urinary t ract infection were more than double those among patients without such infection, although the risks were significantly elevated in both gro ups, Conclusions: Individuals hospitalized for kidney or ureter stones are at increased risk of developing renal pelvis/ureter or bladder ca ncer? even beyond 10 years of follow-up, Chronic irritation and infect ion may play a role, since kidney or ureter stones were located on the same side of the body as the tumors in most patients with renal pelvi s/ureter cancer evaluated in our study.