• Cancer is a leading cause of fire service morbidity and mortality, and a recent National Institute for Occupational Safety and Health (NIOSH) study demonstrated an excess mortality rate for cancer in firefighters compared with the general population.
• Firefighters are exposed to multiple carcinogens in the workplace through skin contamination and inhalation.
• However, we currently do not understand which individual exposures are responsible for cancer in firefighters, the mechanisms by which these exposures cause cancer, or effective means of reducing exposures.
• Since cancer has a long latency period, biomarkers are also needed that can measure the effects of carcinogen exposure well before the development of cancer, when interventions to prevent disease could be effective.
• Development of a large (>10,000 firefighter) multicenter firefighter cancer prospective cohort study will address these needs, but the framework for such a study needs to be first developed and tested among a smaller initial set of fire service partners.
1. Establish an oversight and planning board to provide study oversight, foster communication among fire organizations and help develop a long-term funding plan;
2. Create and test a cohort study data coordinating center and harmonized survey data protocols;
3. Develop and evaluate an exposure tracking system paired with quantitative exposure data to construct a firefighter carcinogen exposure matrix; and
4. Create a biomarker analysis center and evaluate the association between cumulative firefighter exposures and epigenetic effects.
As contrasted with retrospective studies, this proposed prospective study will permit investigators to longitudinally collect information on exposures and other risk factors, while also collecting repeat measures on subclinical effects (e.g. epigenetic endpoints) that may be precursors to cancer. This prospective study design provides a means for investigators to assess the effect of current firefighting practices and exposures on epigenetic endpoints in the short-term (this proposed framework study) and onset of disease in the long term (through follow-on studies). Chemicals to be evaluated include known human carcinogens such as benzene, formaldehyde, some polycyclic aromatic hydrocarbons (PAHs) and diesel engine exhaust, as well as halogenated compounds (chlorinated and brominated flame retardants, perfluorocarbons, etc.) which may also have carcinogenic effects.
Figure. Organization of firefighters' cohort study
Evaluation of early biomarkers of effect, such as epigenetic changes associated with cancer pathways and increased cancer risk, can provide information on which current exposures are associated with cancer effects in firefighters as well as the toxic mechanisms involved. This information is essential to guide interventions to reduce the most important carcinogenic exposures and develop treatment options to potentially reverse carcinogenic effects in their early stages.