Brain cancer in a residential area bordering on an oil refinery

Both in response to community concerns about brain cancer related to an oil refinery and in order to more fully understand the etiology of primary site brain cancer (glioma), a highly focused cancer cluster investigation was conducted. The components included: (1) a literature review of occupational exposures in the petroleum refining and petrochemical industries, (2) comparisons between observed and expected cases, (3) comparisons between mean age at diagnosis and median survival time and (4) interviews concerning exposures of cases. Evidence from the literature review revealed little, if any, effect of petroleum refinery or petrochemical exposure on the risk for brain cancer. There was no statistically significant increase in the number of brain cancer cases in the community (observed = 12, expected = 9.46, standardized mortality ratio = 1.27). There was no statistically significant decrease in mean age at diagnosis or median survival time among those most exposed. Reports of exposure from the case interviews were highest for eating processed meats (98.5%), dental X-rays (96.6%), dog ownership (91.2%) and swimming (80.3%). There were no major occupational exposures identified. It seems unlikely that petrochemicals are involved in any significant way in the etiology of most brain cancers (gliomas). A follow-up case-control study should focus primarily on those risk factors mentioned frequently by the cases.