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By Dick Clapp 

Researchers devote a lot of effort to determining what causes cancer, and their findings can help us treat and prevent the disease. Industries that use and manufacture suspected carcinogens have something to fear, though, if research shows their products or processes to be contributing to cancer in workers or nearby communities.  As a result, there has been a three-decade debate about the magnitude of the cancer burden contributed by these sources.

This issue is getting renewed attention because the International Agency for Research on Cancer (IARC) recently released a report on “Attributable causes of cancer in France in year 2000.”  This was a collaborative effort with the French Academy of Sciences, several other cancer-related agencies, and a distinguished international group of reviewers.  It was begun in 2005 with the intention of updating the frequently-cited estimate of the attributable causes of cancer done by Doll and Peto in 1981, specifically as these estimates applied to France.  The report reviews a large literature, goes through a long series of calculations and sensitivity analyses, and comes up with a set of conclusions remarkably similar to those of Doll and Peto’s estimates 26 years earlier.  They attribute even smaller percentages of cancer due to occupation and “pollution” than did Doll and Peto.

The most surprising aspect of the new IARC report comes in the discussion section, though, where the authors suggest the possibility that low-dose environmental and occupational exposures might actually have decreased cancer incidence in France. In doing so, they invoke the notion of “hormesis.”  Say what?

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By Ruthann Rudel and Dick Clapp

Two recent papers by Ruthann Rudel and Julia Brody published in the journal Cancer compiled a list of 216 chemicals shown to cause mammary gland tumors in animal studies and presented a comprehensive state-of-the-science review of environmental factors in breast cancer.  When such important studies are published, it’s typical for the chemical industry or its surrogates to attack them. In this case, Elizabeth Whelan, president of the industry-backed American Council on Science and Health, fired off a response that questioned whether findings from animal cancer studies are relevant to human cancer risk.  Like many who discount current animal cancer studies, though, Whelan didn’t call for something better; instead, she suggested that better peer review  would have kept these papers out of the scientific literature.

Of course, these two papers had already been through a rigorous peer-review process involving scientists knowledgeable about cancer.  Presumably these scientists were aware of something that most scientists understand: We must rely on animal cancer studies because they are the only thing standing between us and a lot more exposure to chemicals that might cause cancer in humans.

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By Dick Clapp 

Rachel Carson has been in the news quite a lot recently, first as the object of a diatribe by a U.S. Senator, and also in a series of news stories commemorating what would have been her 100th birthday last week.  Tim Lambert at Deltoid has addressed the false allegations about Carson and DDT, so I will focus on Dan Gardner’s rant (Ottawa Citizen, May 25, 2007) denouncing Rachel Carson and the Prevent Cancer Now coalition spokespeople, Liz Armstrong and Angela Rickman, which was startlingly wrong-headed and riddled with errors. 

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By Dick Clapp 

Opponents in the debate over conflict of interest in cancer research are duking it out, and the current forum for their fight is the American Journal of Industrial Medicine. The article that touched off this particular scuffle was “Secret Ties to Industry and Conflicting Interests in Cancer Research,” by Hardell L, et al. (Am J Ind Med 2007;50:227-233), which details a number of examples of researchers working for industries and not disclosing their ties.  The most widely publicized revelations (see this Guardian story) were about Sir Richard Doll, one of the icons of 20th century epidemiology, and his consulting arrangement with Monsanto, Turner and Newall (a British asbestos manufacturer), the Chemical Manufacturers Association, ICI (a British producer of vinyl chloride), Dow Chemicals and others.  Other sections of the Hardell, et al. paper discuss testimony and articles by Dimitrios Trichopoulos, Hans-Olov Adami, Dennis Paustenbach and Jack Mandel regarding dioxin, Joseph McLaughlin and John Boice regarding cell phones and other examples of apparently undisclosed conflicts of interest.

The original article is well worth a read, but the letters in response – published in AJIM’s March 2007 issue—are just as revealing in their own way.

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by Dick Clapp 

The latest issue of Occupational and Environmental Medicine contains a commentary from Ken Mundt, a consultant with ENVIRON International Corporation, on “Cancer incidence among semiconductor and electronic storage device workers,” an IBM-funded study by Bender et al appearing in the same issue. Mundt says that “the study offers some reassurance that at this stage of follow-up no noteworthy increases in cancer risk are seen among employees in the semiconductor production and storage device sectors” (though he notes that additional follow-up should be considered). I believe he is being too quick here to minimize the cancer risk in the semiconductor industry.

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By Dick Clapp

On December 1, NPR’s Living on Earth aired a segment on conflicts of interest in medical research. Host Bruce Gellerman interviewed Dr. Lennart Hardell, lead author of a recent article on conflicts of interest in cancer research published in the American Journal of Industrial Medicine, Catherine DeAngelis, editor-in-chief of the Journal of the American Medical Association, and me. On LOE’s website, there’s also a conversation between Gellerman and Dr. Dimitrios Trichopoulos, one of the researchers whom Hardell and his co-authors criticized in their article.

It’s instructive to examine Hardell’s allegations about Trichopoulos and Trichopoulos’s response, because both are fairly typical of the widespread dilemma of conflicts of interest in medical research.

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by Dick Clapp

Atul Gawande is well-known around Boston because of his skills as a surgeon, but also for his books and articles in the New Yorker, and his interviews with local media.  He was a recipient of one of this year’s MacArthur grants, in recognition of his work. I got one of his books, “Complications,” as a gift and read it and liked it a lot.  He’s an incredibly talented writer, and he has ahumane surgeon’s view of medical practice.  My father was a surgeon too, so his book resonated with me.

I have another response to Atul Gawande, though, based on an article he wrote for the New Yorker in 1999 called “The Cancer-Cluster Myth.”  (PDF here)

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