No Evidence of Dioxin Cancer Threshold

The study mentioned below helps build our argument that there is NO SAFE DOSE of dioxin. Often, polluting interests will argue that the amount of pollution they are releasing is "safe" because they project that people will receive a dose that is below the level at which the chemical in question can cause harm (usually defined as a cancer death in a healthy, adult, white male exposed to only one chemical at a time). The study below refutes an industry claim that there is a safe "threshold" dose - below which dioxin won't cause cancer. As with radiation, dioxin appears to be dangerous at ANY level, no matter how small.

10/28/03 Cancer Res. Wkly. 40

2003 WL 59748736

Cancer Weekly

(c) Copyright 2003 Cancer Weekly via

Tuesday, October 28, 2003

Cancer Risk; Re-analysis of data finds no evidence of dioxin cancer threshold

2003 OCT 28 - ( & -- Re-analysis of data finds no evidence of dioxin cancer threshold. According to a study from the United States, "The U.S. Environmental Protection Agency (EPA) has developed an estimate of the human cancer risk from dioxin, using the standard low-dose linear extrapolation approach."

"This estimate has been controversial because of concern that it may overestimate the cancer risk. An alternative approach has been published and was presented to the U.S. EPA Science Advisory Board's Dioxin Review Panel in November 2000," wrote D. Mackie and colleagues, Princeton University, Princeton Environmental Institute.

"That approach suggests that dioxin is a threshold carcinogen and that the threshold is an order of magnitude above the exposure levels of the general population," the researchers wrote.

The researchers concluded: "We have reexamined the threshold analysis and found that the data have been incorrectly weighted by cohort size. In our reanalysis, without the incorrect weighting, the threshold effect disappears."

Mackie and colleagues published their study in Environmental Health Perspectives (No evidence of dioxin cancer threshold. Environ Health Perspect, 2003;111(9):1145-1147; click here for abstract).

For more information, contact V. Thomas, Princeton University, Princeton Environmental Institute, Guyot Hall, Princeton, NJ 08544, USA.

Publisher contact information for the journal Environmental Health Perspectives is: U.S. Department of Health and Human Sciences, Public Health Science, National Institutes of Health, National Institute of Environmental Health Sciences, PO Box 12233, Research Triangle Park, NC 27709-2233, USA.

The information in this article comes under the major subject area of Oncology.

This article was prepared by Cancer Weekly editors from staff and other reports.

Click here for the full study.

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Last modified: 16 November 2003