Noise about cancer

October 2015

Photo Creative Commons
The manufacturer of glyphosate-based herbicides and glyphosate-tolerant GM crops was quick to 'disagree' with the International Agency for Research on Cancer (IARC) reclassification of its prize agrichemical as a 'probable carcinogen' [1].

Besides the usual disparaging remarks about the IARC, the gist of Monsanto's disagreement was one we've heard repeatedly. Since the industries' own (unpublished) studies have successfully persuaded regulators (who didn't have anything much else to go on) that glyphosate is safe, it is therefore proven safe.

Monsanto also made a good attempt to fudge the issue. It suggested that no link had been established between glyphosate and cancer incidence in humans. This needs to be put in perspective.
The IARC used only reliable (published) studies in its assessment: this basic quality control measure cut out the 'noise' of industry bias in the science which regulators have relied on. It found sufficient evidence of carcinogenicity in animal studies and strong evidence of glyphosate's role in genotoxicity (damaged genes) and oxidative stress (damaging substances produced during stress), both of which cause cell damage linked to cancer.

If clear epidemiological data had supported this laboratory-based science, glyphosate would have been classified as a definite 'carcinogen'. However, in the words of the head of the IARC, "the epidemiological data was a little noisy". What he meant was that, while several population studies suggested a link between glyphosate and cancer, the biggest (and ongoing) study examining cancer incidence in American pesticide-applicators concluded only that "There was a suggested association with multiple myeloma incidence that should be followed up as more cases occur in the (study)".

Monsanto had already published a re-analysis of this American study which refuted its conclusion. The trick used was to include all the data collected. The authors of the study had refined their data down to cases where the collected data were complete. This enabled them to include important additional cancer risk factors in their analyses. Put another way, they used cases realistically more likely to be susceptible to cancer in the first place. Adding in data from cases less likely to get cancer simply creates the noise needed to drown out the cancer connection. Good try!

Another source of 'noise' in epidemiological studies is that, while farmers etc. who handle glyphosate professionally have been found to have the herbicide in their urine, much of the rest of the population (which was used to provide the 'non-exposed' control group) have too.

In 1993, the US Environmental Protection Agency also re-classified glyphosate. It altered the original classification from 'possible carcinogen' to 'non-carcinogen'. As a result "millions of gallons of herbicide with carcinogenic potential have been used according to regulations designed for a virtually harmless substance" (Fernando Manas quoted by the Institute of Science in Society 9.09.15), and the lives and bodies of the US public are now heavily infiltrated with glyphosate herbicide.

Glyphosate sources include GM staple crops genetically transformed to accumulate the herbicide, plus non-GM staple crops (such as wheat) treated with glyphosate in preparation for harvest, plus staple meat and dairy from GM-fed livestock.

Besides eating glyphosate, they can be exposed to the herbicide after its use in parks, roadways, and in their own gardens. Glyphosate is also in the air they breath and the water they drink. The latter sources are boosted by the American phobia of invasive plant species: in 2014, 90% of California State land managers preferentially used glyphosate, to slay the dreaded eucalyptus tree. 

Ironically, persistent and increasing use of the herbicide in agriculture has created uncontrollable monsters: native weeds which have become the ultimate "alien invasion right here in America" (Cockburn). And, since the IARC has noted that glyphosate is a probable carcinogen, the American public might well be under attack from another kind of alien invader right inside them.

Create a monster noise of your own: demand carcinogenic glyphosate-based herbicides are removed from you food-supply chain.


  • Glyphosate is Carcinogenic, Institute of Science in Society Report, 9.09.15
  • Monsanto disagrees with IARC Classification for Glyphosate, Monsanto Newsroom, 20.03.15
  • Andrew Cockburn, Weed Whackers, Harpers Magazine September 2015
  • New revelation about glyphosate-cancer link, GM Watch, 13.08.15
  • Anneclaire J. De Roos, et al., 2005, Cancer Incidence amoung glyphosate-Exposed Pesticide Applicators in the Agricultural Health Study, Environmental Health Perspectives 113:1
  • Brian D. Curwin, et al., 2007, Urinary Pesticide Concentrations Among Children, Mothers and Fathers Living in Farm and Non-Farm Households in Iowa, Annals of Occupational Hygeine 51:1
  • Tom Sorahan, 2015, Multiple Myeloma and Glyphosate Use: A Re-Analysis of US Agricultural Health Study (AHS) Data, International Journal of Environmental Research: Public Health 12

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