EXPERT REACTION: Cancer Council calls for review of 'Round-up' herbicide

Embargoed until: Publicly released:
The Cancer Council is reported to be calling for an independent review into the weedkiller, glyphosate  — the active ingredient in Roundup. In 2015 the World Health Organisation's specialised cancer agency, the International Agency for Research on Cancer (IARC), classified glyphosate as "probably carcinogenic to humans".

Organisation/s: The University of Adelaide, The University of Sydney, The University of Western Australia

Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Lin Fritschi is a Professor of Epidemiology within the School of Public Health, Curtin University, Western Australia.

The International Agency for Research in Cancer is a reputable body which undertakes reviews of published studies on agents to determine whether they are carcinogenic.  The Working Group is made up of 19 scientists with expert knowledge of the topic.  For those scientists, all potential conflicts of interest are declared and publicized and the names of the scientists are publicly available. All the procedures for each of the reviews are clearly set out on documents on the website.  The whole process concentrates on the science.

Last updated: 09 Oct 2018 9:38am
Declared conflicts of interest:
I was on the IARC Working Group which made the decision that glyphosate was a probable carcinogen.
Dr Richard Gordon, is Group Leader in Clinical Neuroscience at the UQ Centre For Clinical Research. He is a Board Certified Toxicologist (DABT) and regulatory consultant in Toxicology.

Several independent regulatory authorities worldwide have comprehensively reviewed the safety and potential carcinogenicity of glyphosate over the last three to four decades. These include the European Commission (2002), the US Environmental Protection Agency (1993 and 2013), the Canadian Pest Management Regulatory Agency (1991 and 2015) and the World Health Organisation (1994). The conclusion of these comprehensive and independent expert reviews is that based on the available evidence, proper use of glyphosate and other glyphosate-based formulations (GBFs) does not pose a carcinogenic risk to humans. If credible new evidence has emerged that clearly demonstrated a previously unrecognised risk or pathway to carcinogenicity, this could potentially justify a review of the glyphosate use and regulation in Australia. In the absence of any compelling new evidence, an Australian regulatory review of glyphosate use is not likely to result in major changes to the regulations and guidelines that are currently in place. Such a review may however help identify potential gaps in current regulations  or identify potentially unsafe or higher risk users of glyphosate thereby facilitating safer use, storage and disposal in Australia.

Last updated: 09 Oct 2018 9:36am
Declared conflicts of interest:
None declared.
Professor Ian Rae is an expert on chemicals in the environment at the School of Chemistry at the University of Melbourne. He is also an advisor to the United Nations Environment Programme on chemicals in the environment and is former President of the Royal Australian Chemical Institute.

Since the last Australian review, glyphosate has been reviewed by a number of other jurisdictions, with mixed findings. I conclude that, if glyphosate is a carcinogen, it's a pretty weak one. so its impacts are hard to distinguish from those of other factors that might lead to cancer. APVMA would be wise to conduct a review, reminding us of those overseas findings, reviewing the most recent literature, and evaluating the risks to Australian users, consumers and wildlife.

Last updated: 08 Oct 2018 3:47pm
Declared conflicts of interest:
None declared.
Emeritus Professor Bruce Armstrong is an independent consultant with expertise in cancer causes and prevention. He is also Emeritus Professor in the School of Public Health at the University of Sydney and Adjunct Professor, School of Global and Population Health at the University of Western Australia

I agree wholeheartedly with the Cancer Council’s call. An IARC 'probably carcinogenic' classification is made when there is reasonably strong, but not conclusive, evidence that something, in this case glyphosate, can cause cancer in humans. IARC is a highly respected organisation and its evaluations of carcinogenic risks to humans are very carefully prepared. Responsible governments should take them seriously

Last updated: 08 Oct 2018 12:51pm
Declared conflicts of interest:
None declared.
Dr Ian Musgrave is a Senior Lecturer in the Faculty of Medicine, School of Medicine Sciences, within the Discipline of Pharmacology at the University of Adelaide.

Glyphosate is one of the most widely used herbicides in Australia, used in weed management by agriculture, council authorities and home gardeners.

Glyphosate targets an enzyme that is found only in plants and some bacteria, and so has little toxicity in animals. For acute exposures, it is slightly less toxic than table salt.

Glyphosate's potential to cause cancer has been more controversial. In 2015 the International Agency for Research on Cancer classified glyphosate as "probably carcinogenic to humans". However, the IARC consider any possibility of producing cancer at any exposure, even at extremely unrealistic levels of glyphosate intake.

Subsequent evaluations from the European Food Safety Authority, the WHO Core Assessment Group on Pesticide Residues and the Australian Pesticides and Veterinary Medicines Authority all concluded that at usual use levels, glyphosate was not a cancer risk.

A recent jury ruling that a glyphosate formulation was responsible for a man’s non-Hodgkins leukaemia has reignited debate, with the Australian Cancer Council calling for a review of glyphosate safety (presumably they think the APVMA 2016 review was not adequate).

Two points must be made. Juries do not decide science, this is but one of a series of jury decisions where scientific evidence has been relegated to a back seat (coffee and cancer is another recent one).

The second is that after the 2015 IARC monograph, the massive independent Agricultural Health Study came out. This study followed over 50,000 people for over 10 years showed no association between cancer and glyphosate formulations, including non-Hodgkins leukaemia. Herbicide safety is periodically reviewed in all countries, and the recent re-evaluation by the AVPMA, combined with the latest epidemiological data, once again reinforces that glyphosate is of very low risk when used appropriately

Last updated: 08 Oct 2018 12:47pm
Declared conflicts of interest:
None declared.

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