Carcinoma of the Pharynx and Tonsils in an Occupational Cohort of Asphalt Workers

Background: We investigated a possible association between pharyngeal/tonsillar carcinoma and mixed carcinogen exposures in an asphalt roll company that used asbestos until 1979. Methods: We evaluated all workers involved in the entire production history of the company, divided into two subcohorts based on exposure status (workers exposed to the 'old' factory, 1964–79, and workers exposed only to the 'new' factory, 1980–97). We ascertained the vital status of the study population in February 2001. Results: Deaths from pharyngeal/tonsillar carcinoma (n=5) among the subset of workers in the earlier subcohort who were occupationally exposed to the production line sector corresponded to a standardized mortality ratio (SMR) of 21.1 (95%CI, 8.8–50.7); no further case was recorded in the new factory. Conclusion: The elevated SMR for this relatively rare cancer among workers exposed to the production line of the initial factory may not have been merely play of chance.