Australian Cancer Council calls for review of ‘Round-up’ — Expert Reaction

The Australian Cancer Council is reported to be calling for an independent review into the weedkiller, glyphosate  — the active ingredient in Roundup.

This was widely reported by the Australian media, following the ABC’s Four Corners documentary on The Monsanto Papers, which aired on Monday night, that centred around Monsanto’s possible cover-up of the evidence for a link between glyphosate and cancer.

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”. Back in August, Environment Minister Eugenie Sage has said she will be asking the Environmental Protection Agency (EPA) to consider adding Roundup to a list of hazardous substances up for reassessment after a court case in the US awarded US$289m ($440m) to a groundskeeper who said his lymphoma was caused by a lifetime’s use of the weedkiller.

Our colleagues at the Australian Science Media Centre asked experts to comment. Feel free to use these comments in your reporting.

Prof Lin Fritschi, Professor of Epidemiology within the School of Public Health, Curtin University, Western Australia, comments:

“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.”

Conflict of interest statement: I was on the IARC Working Group which made the decision that glyphosate was a probable carcinogen.

Dr Ian Musgrave, Senior Lecturer in the Faculty of Medicine, School of Medicine Sciences, University of Adelaide, comments:

“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.”

Ian has not declared any conflicts of interest. Ian also wrote a piece on The Conversation about The Monsanto Papers.

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. He comments:

“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.”

Bruce has not declared any conflicts of interest.

Dr Richard Gordon, Group Leader in Clinical Neuroscience, 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.”

Richard has not declared any conflicts of interest.

Professor Ian Rae, environmental chemist, School of Chemistry, University of Melbourne.

“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.”

Ian has not declared any conflicts of interest.