Alavanja was one of the authors of the paper published in PLoS One in 2014. He said he and other authors and senior scientists at the National Cancer Institute decided to remove herbicides from that analysis primarily because of “the issue of statistical power and the need for a comprehensive evaluation of glyphosate and all cancers.”
Blair told Reuters the data on herbicides, including glyphosate, had been removed “to make the paper a more manageable size.” He gave a similar answer to the lawyer acting for Monsanto, who repeatedly asked in the legal deposition why the data was not published. Blair testified that the paper “went through many iterations.” He said he could not recall when the glyphosate data was removed, but “we decided to remove it because…you couldn’t put it all into one paper.”
Monsanto argues that the data was not published because it showed no link between glyphosate and non-Hodgkin lymphoma.
Tarone said the absence of herbicide data in the published 2014 paper was “inexplicable,” noting that volume of data had not been an issue in any previous published papers. He said updated AHS data and analyses on herbicides “should be published as soon as possible” to allow “a more complete evaluation of the possible association between glyphosate exposure and NHL risk in humans.”
Reuters asked nine other scientists listed as authors on the two draft papers of 2013 why these drafts had never been published. Some were unavailable for comment, and others referred questions to Laura Beane Freeman, who was a co-author on the draft papers and on the 2014 PLoS published study, and is the National Cancer Institute’s current principal investigator of the AHS.
In an email to Reuters, Freeman and a spokesman for the institute said: “After reviewing early drafts of the manuscript, it became clear that it would be impossible to do a thorough evaluation of all major pesticide groupings due to the sheer volume of information that was important to include.”
They said the decision to separate the results for herbicides, including glyphosate, allowed the scientists “to present more thorough evaluations” of the remaining pesticides. An updated study on glyphosate is under way, Freeman said.
Despite IARC’s modest size and budget, its monographs—assessments of whether something is a cause of cancer—often catch the eyes and ears of policymakers and the public. Recent IARC monographs have included judgments that red meat is carcinogenic and should be classified alongside arsenic and smoking, and that coffee, which IARC previously said might cause cancer, probably is not carcinogenic.
The agency takes a different approach to many other regulators in two important ways. First, it says it assesses “hazard”—the strength of evidence about whether a substance or activity can cause cancer in any way, whether in a laboratory experiment or elsewhere. It does not assess the “risk” or likelihood of a person getting cancer from everyday exposure to something. Second, in general it only considers research that has been published in peer-reviewed scientific journals.
IARC considered around 1,000 published studies in its evaluation of glyphosate. But only a handful of those were cohort studies in humans—the kind like the Agricultural Health Study and the most relevant to real-life situations such as people working with glyphosate in agriculture.
The differing judgments on glyphosate by IARC and other regulators have stoked clashes on both sides of the Atlantic. In the U.S. members of Congress have launched investigations into American taxpayer funding of IARC. They have yet to reach any conclusions.
In Europe, the battle centers on the looming decision about whether to re-license glyphosate for use in the European Union. The European Commission has said it wants EU member states to come to a decision by the end of 2017. Politicians will need to weigh the opinions of IARC and other scientific bodies when they decide whether or not to accept a Commission proposal to extend glyphosate’s marketing license by 10 years.