Cancer incidence and cancer mortality in a cohort of UK semiconductor workers, 1970-2002

OBJECTIVE: To examine cancer risks in a cohort of workers employed in the manufacture of semiconductors. METHODS: The mortality (1970-2002) and cancer morbidity (1971-2001) experienced by a cohort of 1807 male and female workforce employees from a semiconductor factory in the West Midlands (UK) have been investigated. Standardized mortality ratios (SMRs) and standardized registration ratios (SRRs) were used to assess mortality and morbidity, respectively. RESULTS: Overall mortality was close to expectation in males [SMR 99, 95% (confidence interval) CI 79-122] and significantly below expectation in females (SMR 74, 95% CI 65-85). Incidence of all sites of cancer was somewhat elevated in males (SRR 130, 95% CI 95-173) but close to expectation in females (SRR 94, 95% CI 82-109). There were significant deficits of deaths from cancer of the oesophagus in males and females combined and from cancer of the breast in females. Significantly elevated SRRs were found in males for cancer of the rectum [Observed (Obs) 6, SRR 284, 95% CI 104-619], in females for cancer of the pancreas (Obs 10, SRR 226, 95% CI 108-415) and malignant melanoma (Obs 11, SRR 221, 95% CI 110-396) and in males and females combined for cancer of the rectum (Obs 19, SRR 199, 95% CI 120-310) and malignant melanoma (Obs 12, SRR 217, 95% CI 112-379). Detailed work history data were unavailable for analysis. The finding of excess morbidity was not mirrored in the corresponding mortality findings. CONCLUSIONS: The study found elevated morbidity for a number of cancer sites that may be unconnected with occupation. Elimination of all possible occupational causes will, however, require more detailed analyses of cancer risks in relation to exposure histories.