Chemicals and Cancer
By Nachman Brautbar, M.D
Chemical exposure and cancer date back several thousand years. The famous occupational physician, Ramazzini, was one of the first to describe examples of occupationally-induced cancers.
In the last 20 years, benzene has been shown to be a carcinogenic agent causing leukemias, lymphomas, and other hematological cancers. Other chemicals, such as chlorinated hydrocarbons, asbestos, and hexavalent chromium, have been shown to be carcinogenic.
The observation that despite reduction in cigarette consumption, despite reduction in fatty food consumption and despite improved screening procedures, cancers of the lung, breast, and blood system is on the rise and is by and large attributed to a combination of environmental chemical factors imposed on the genetic makeup of the individual.
I. Causation - Definition
Causation, meaning cause and effect, is one of the most important and complex duties a forensic-medicolegal examiner has to establish. As physicians practicing medicine, we have been trained to think etiology of a disease which does not necessarily mean causation. The training in medical school, internship residency and fellowship always addressed etiology synonymously with causation, but we were not taught the practical meaning of the word causation.
The medical scientific community has been struggling with this issue of causation since the early days of Paracelsus. The first criteria for causation were established by Henle and Koch when Henle and his students, including Koch, studied cholera in the 1880's. These criteria have changed through the years undergoing natural evolution. With new discoveries, Henle and Koch's criteria were no longer valid for viruses and cancers. In the 1960's Sir Bradford-Hill, who studied the cancerous effects of cigarettes, nickel and others, presented his aspects to establish medical causation. These criteria have been endorsed to some extent by the scientific community and utilized in occupational medicine and medical toxicology.(1) For more details visit www.environmentaldiseases.com.
About the Author
"Dr. Nachman Brautbar is a board-certified internist and nephrologist, with a specialization in toxicology.For more details go to http://www.environmentaldiseases.com.
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