Occupational aetiologies of laryngeal cancer: is there a difference in comparison to (hypo) pharyngeal cancer?

Introduction: The two major recognized risk factors for laryngeal cancer are tobacco and alcohol consumption. However, according to WHO and IARC, occupational factors are probably underestimated. Confirmed/highly probable occupational carcinogens related to laryngeal cancer include asbestos and strong organic acid mists. Probable carcinogens are cement, polycyclic aromatic hydrocarbons (PAH) and wood dust. Suspected carcinogens are organic solvents, formaldehyde, coal/silica dust, leather dust and cotton dust. An important problem of epidemiological studies appears to be the lack of differentiation between laryngeal and hypopharyngeal (squamous cell) carcinomas. Material and Methods: For the purposes of this study, a database of 164 well-documented cases of laryngeal and hypopharyngeal cancers was created by collecting data from 4 centres in Belgium, Italy and France. In order to identify confirmed, probable and suspected carcinogenic risks, jobs and exposures over the whole career of the patients were exhaustively identified and mapped. Confounding factors were taken in account. Results: In general, occupational exposure to known or suspected carcinogens is significantly higher in laryngeal than in hypopharyngeal carcinomas. As regards the exposed subjects, the global occupational exposure profiles differ significantly (10 categories). Asbestos and acid mist exposures are significantly more important in laryngeal carcinoma. Coal/silica dust exposure is significantly more important in pharyngeal carcinoma..