Excess risk of bladder cancer in spinal cord injury: evidence for an association between indwelling catheter use and bladder cancer.

OBJECTIVES

To evaluate whether the risk of bladder cancer is greater in individuals with spinal cord injury (SCI) than in the general population and whether indwelling catheter (IDC) use is a significant independent risk factor for bladder cancer.

DESIGN

Historical cohort study in which subjects with SCI were stratified according to bladder management method and followed for the development of bladder cancer.

SETTING

A large rehabilitation hospital in the Spinal Cord Injury Model Systems.

PARTICIPANTS

A total of 3670 patients with SCI who were evaluated for bladder cancer on at least 1 occasion by cystoscopy over a period of 1 to 47 years.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Bladder cancer occurring after SCI determined by diagnosis at our facility, by subject report, or by report of next of kin.

RESULTS

Twenty-one cases of bladder cancer were found in the 3670 study participants. The risk of bladder cancer for subjects with SCI using IDC is 77 per 100,000 person-years, corresponding to an age- and gender-adjusted standardized morbidity ratio (SMR) of 25.4 (95% confidence interval [CI], 14.0--41.9) when compared with the general population. After controlling for age at injury, gender, level and completeness of SCI, history of bladder calculi, and smoking, those using solely IDC had a significantly greater risk of bladder cancer (relative risk [RR] = 4.9; 95% CI, 1.3--13.8) than those using nonindwelling methods. Mortality caused by bladder cancer in individuals with SCI was significantly greater than that of the US population (SMR = 70.6; 95% CI, 36.9--123.3).

CONCLUSIONS

Bladder cancer risk and mortality are heightened in SCI compared with the general population. IDC is a significant independent risk factor for the increased risk of and mortality caused by bladder cancer in the SCI population.