Tumours of the central nervous system are relatively rare and include tumours in the brain, cranial nerves, or cranial meninges.
Environmental
High-dose ionizing radiation is a well-recognized risk factor for brain tumours; however, the general population is not generally exposed to high doses, and the association with low doses is controversial. Although there have been some studies reporting elevated brain tumour risk with occupational exposure to benzene or work in the petrochemical industry, other studies have not confirmed these results.
Elevated risks for brain tumours among agricultural workers, and workers in the nuclear and rubber industries have been reported; but the specific causative agents have not been established for these associations. N-nitroso compounds, potent nervous system carcinogens in animals, are hypothesized to be causative agents in brain tumours. Human exposure to these compounds is through tobacco smoke (in particular, sidestream smoke), cosmetics, cured meats, and other N-nitroso containing foods. Studies of pediatric and adult tumours so far have provided limited support for the role of these compounds in human CNS tumours.
Three of the four case-control or cohort studies of meningioma show an elevated risk in subjects with prior head trauma. The relative risks are about 2-fold. Nerve sheath tumours appear to be more common in subjects reporting acoustic trauma.
Prevention
At this time, not enough is understood of the factors influencing risk of brain tumours to make recommendations for prevention.
References:
Preston-Martin S, Mack WJ,. Neoplasms of the nervous system. In Schottenfeld D, Fraumeni JF Jr. (Eds) Cancer Epidemiology and Prevention.2nd Ed., Oxford University Press, Oxford, Pp1231-1281. 1996.
