A review of the carcinogenic potential of glyphosate by four independent expert panels and comparison to the IARC assessment

Abstract

The International Agency for Research on Cancer (IARC) published a monograph in 2015 concluding that glyphosate is "probably carcinogenic to humans" (Group 2A) based on limited evidence in humans and sufficient evidence in experimental animals. It was also concluded that there was strong evidence of genotoxicity and oxidative stress. Four Expert Panels have been convened for the purpose of conducting a detailed critique of the evidence in light of IARC's assessment and to review all relevant information pertaining to glyphosate exposure, animal carcinogenicity, genotoxicity, and epidemiologic studies. Two of the Panels (animal bioassay and genetic toxicology) also provided a critique of the IARC position with respect to conclusions made in these areas. The incidences of neoplasms in the animal bioassays were found not to be associated with glyphosate exposure on the basis that they lacked statistical strength, were inconsistent across studies, lacked dose-response relationships, were not associated with preneoplasia, and/or were not plausible from a mechanistic perspective. The overall weight of evidence from the genetic toxicology data supports a conclusion that glyphosate (including GBFs and AMPA) does not pose a genotoxic hazard and therefore, should not be considered support for the classification of glyphosate as a genotoxic carcinogen. The assessment of the epidemiological data found that the data do not support a causal relationship between glyphosate exposure and nonHodgkin's lymphoma while the data were judged to be too sparse to assess a potential relationship between glyphosate exposure and multiple myeloma. As a result, following the review of the totality of the evidence, the Panels concluded that the data do not support IARC's conclusion that glyphosate is a "probable human carcinogen" and, consistent with previous regulatory assessments, further concluded that glyphosate is unlikely to pose a carcinogenic risk to humans. ARTICLE HISTORY

Re-registration Challenges of Glyphosate in the European Union

“…Among environmental factors, glyphosate or its formulated products have been indicated to be linked with increased incidence of and mortality by multiple diseases (including cataract related to subsequent breast carcinoma) and cancer (Swanson et al, 2014;Singh et al, 2017). In the latter category, associations were found with non-Hodgkin lymphoma or multiple myeloma incidence (Hardell and Eriksson, 1999;McDuffie et al, 2001;Hardell et al, 2002;De Roos et al, 2003Eriksson et al, 2008;Schinasi and Leon, 2014;Mesnage et al, 2015b), although other reviews claimed no causal relationship between exposure to glyphosate and lymphohematopoietic cancers (Acquavella et al, 2016;Chang and Delzell, 2016;Williams et al, 2016a). Some of these findings have been questioned by Monsanto (Acquavella et al, 1999) and a recent cohort prospective epidemiology study carried out in the US on 57310 licensed pesticide applicators and 32347 spouses in Iowa or North Carolina States found no apparent correlation between glyphosate use and solid tumor or lymphoid malignancies, including non-Hodgkin lymphoma, except for increased risk of acute myeloid leukemia in case of high exposure (Andreotti et al, 2018).…”

Critical Review of the Effects of Glyphosate Exposure to the Environment and Humans through the Food Supply Chain

“…Furthermore, the experts argued that, by analyzing the data available until before the publication of the IARC, there was no such document that would allow the Agency to change the conclusions on the carcinogenicity of the glyphosate disclosed up to that time. The conclusions of the research clearly stated that glyphosate did not pose any risk to humans [54,55].…”

“…The company stated that, from the results obtained, it was evident that, despite the worst conditions of exposure, there was no risk associated with exposure through the normal use of the product in agriculture or to manage weeds along roadsides or in domestic and industrial areas [54][55][56][57].…”

“…In this regard, the experts clarified the fundamental differences between the evaluation methods adopted by the IARC and those they would use in the course of the research [9,10,54,55]. The Lyon Agency, according to the panel of scientists, did not take into account some important studies and this also led to a completely different approach to evaluating available data.…”

The rise and future of glyphosate and glyphosate‐resistant crops

“…The health issue was reignited in 2015 when the International Agency for Research on Cancer (IARC) published a monograph concluding that glyphosate is ‘probably carcinogenic to humans’ . The US Environmental Protection Agency and others have since concluded that glyphosate is likely not a carcinogen, but the firestorm over its safety continues in both popular press and scientific publications . In addition, concerns are often raised about the safety of glyphosate formulations that contain the original tallow amine ethoxylate ‘Roundup surfactant.’ This surfactant type has known aquatic and eye toxicity issues that are commonly addressed with mandatory application restrictions and requirements for operators to wear personal protective equipment (PPE).…”