Mortality and cancer experience of Quebec aluminum reduction plant workers, part 4: cancer incidence.

Abstract

To describe the cancer experience of Quebec aluminum smelter workers. Cancer incidence was compared with that of the Quebec general population and examined in relation to benzo[a]pyrene (B[a]P) and smoking exposure indices. There was a statistically significant increased incidence of stomach (two cohorts), pancreatic (one cohort), laryngeal (one cohort), lung (three cohorts), and bladder (four cohorts) cancers. Unlike lung and bladder cancers, pancreatic and stomach cancer risks do not relate meaningfully to cumulative B[a]P exposure. Laryngeal and buccal cavity cancer standardized incidence ratios (SIRs) seem to increase with increasing B[a]P exposure. SIRs from lung cancer have greatly diminished whereas bladder cancer SIRs remain elevated in all but one cohort. The cancer incidence results are consistent with those from mortality studies, but identify other cancers that deserve scrutiny in future follow-ups.