Occupation and Bladder Cancer Phenotype: Identification of Workplace Patterns That Increase the Risk of Advanced Disease Beyond Overall Incidence

Abstract

Background: We examined a national data set to determine if workers employed in specific occupations develop distinct bladder cancer (BCa) phenotypes.

Objective: To compare the incidence and disease-specific mortality (DSM) of localized and advanced BCa in workers with different job titles.

Design, setting, and participants: BCa incidence, stage at diagnosis, and DSM in 1.7 million Finnish men (13 717 with BCa) and 1.7 million women (4282 with BCa) with annotated occupational descriptions. Follow-up was 37 and 43 million person-years, respectively.

Outcome measurements and statistical analysis: The gender-specific incidence and BCa DSM within each occupational category was compared with the expected number of cases based on the entire Finnish population to generate standardized incidence ratios (SIRs) and standard mortality ratios (SMRs).

Results and limitations: Occupations were found that had significant differences in the incidence of localized (SIR_loc) and advanced (SIR_adv, SMR_adv) BCa and DSM. Male chemical process workers (SIR_loc/SIR_adv: 5.19; 95% confidence interval [CI], 1.73-25.7), male military personnel (SIR_loc/SIR_adv: 6.4; 95% CI, 1.09-259.0), and male public safety workers (SIR_loc/SIR_adv: 1.77; 95% CI, 1.04-3.23) had significantly more localized than advanced tumors. In contrast, miscellaneous construction workers had more advanced than localized cancers for both genders (male SIR_loc/SIR_adv: 0.67; 95% CI, 0.53-0.86; female SIR_loc/SIR_adv: 0.12; 95% CI, 0.09-0.54). Male chemical process workers had fewer deaths from BCa than expected from advanced tumors (SMR_adv: 0.32; 95% CI, 0.07-0.94), and miscellaneous constructions workers had more deaths from advanced tumors than expected (male SMR_adv: 1.44; 95% CI, 1.10-1.85; female SMR_adv: 3.35; 95% CI, 1.23-7.30). Limitations of this study are failure to control accurately for the effects of smoking and a lack of specific treatment information.

Conclusions: Occupations exist that may differ in their risks for localized and advanced BCa and for DSM.

Patient summary: Occupations have been identified that may have different patterns of bladder cancer than expected. These findings may be explained by confounding factors such as exposure to tobacco smoke; however, it could be that workers with these job titles are exposed to specific bladder carcinogens.

Keywords: Carcinogens; Industry; Occupations; Phenotype; Urinary bladder neoplasms; Workplace.