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Health Canada’s Glyphosate Conclusion On Cancer Untenable
A review article by Williams, Kroes Munroe was used by Health Canada to buttress its conclusion that glyphosate is “unlikely to pose a human cancer risk.” But the article has now been retracted, and the credibility of the studies it reviewed are in question.
Weight of evidence not there
When PMRA re-registered glyphosate in 2017, its review for “chronic toxicity/ oncogenicity” consisted of 6 studies – five in its database, plus a CD-1 mouse study authored by Knezevich and Hogan.
Three of the six were part of the now-retracted Williams review, and their credibility is in issue. That leaves three.
In one of these three (PMRA #1161786), PMRA found “equivocal evidence of oncogenicity” – meaning the cancer finding was uncertain.
That leaves only two of the six studies in support of Health Canada’s conclusion. Thus PMRA’s cancer conclusion is untenable.
PMRA did NOT conduct an Independent Review
PMRA did not conduct its own independent review of these 6 studies. In the RVD 2017-01 decision document (p. 20), PMRA said it didn’t see all the studies and it looked at other reviews:
“As reported in PRVD2015-01, the PMRA also assessed the carcinogenic potential of glyphosate in several long-term animal studies, which included two mouse studies and four rat studies, as well as studies in the published literature. Although, not all available carcinogenicity studies on glyphosate were submitted to the PMRA, reviews, evaluation reports, and committee meeting documents from international regulatory authorities (EFSA and USEPA) for these particular studies were considered by the PMRA.”
As shown below, the PMRA reviewed evaluation reports from foreign authorities and the PMRA when looking at the 6 studies (Toxicology Monograph App.5 PMRA #2222272). Appendix III (p79-80) of the Proposed Re-evaluation Decision PRVD 2015-01 sets out the PMRA conclusions.
(Note the PMRA comments on these studies, and how the comments in the Williams, Kroes Munro article accord with the PMRA review comments.)
| Study PMRA Doc # Conclusion |
Foreign Review Consulted | PMRA Reviewer Comments
(reason for dismissal of finding in italics) |
| Atkinson mouse #1161786
EQUIVOCAL EVIDENCE OF ONCOGENICITY
|
Joint Meeting on Pesticide Residues (JMPR) (2004) | “…increase in the number of animals in the high dose group of both sexes having multiple tumour types…” – Increased incidence mineral deposits in the brain in 2 highest dose groups. – All groups: dose-related decreased adrenal weights males, increased ovary and thymus weights in females. –Males mid-dose: increased thymus, lung and liver weights. –Females top 2 doses: increased incidence unilateral ovarian tubulostromal hyperplasia, and high dose had adenoma. |
| Lankas rat #1184837REVIEW RETRACTED |
USEPA Reregistration Eligibility Decision (RED) (1993)
USEPA Glyphosate HH Risk Assessment for Proposed use on Indian Mulberry and Amended use on Pea, Dry (2006) PMRA (1991) Discussion Document Glyphosate |
– Increased incidence of interstitial cell testicular tumours. Considered “unlikely to be treatment related”. – Increased incidence of thyroid C-cell carcinomas. Independent consultants discounted the relationship. |
| Stout & Reucker rat #1235214REVIEW RETRACTED |
JMPR (2004)
RED (1993) EPA (2006) PMRA (1991) |
– Increased incidence gastric squamous mucosa in mid-dose females. Not considered treatment related because no dose-response. – Increased incidence of C-cell adenomas. Probably a reflection of hormonal imbalance. -C-cell adenomas. Occurred considerably after the appearance of pituitary tumours. -Increased incidence of pancreatic islet cells adenomas. Not considered treatment related. |
| Atkinson rat #1161796No evidence of carcinogenicity |
JMPR (2004)
European Food Safety Authority (2012) |
-Increased incidence and severity of cellular alteration in the submandibular and parotid glands starting in second lowest dose group. -Increased activity ALP in high dose males.“Study report did not contain data to show whether sublingual salivary gland was affected”. |
| Brammer rat 1212011No evidence of carcinogenicity |
JMPR (2004) | -Red-brown staining of tray paper in all dose groups. –Salivary gland histopath findings. Sublingual glands were not studied histoligically. –Increased activity levels of ALP, ALT and AST starting mid-dose. Males mid-dose decreased plasma creatinine. Males high-dose increased total bilirubin, decreased triglycerides and chloesterol levels, and decreased urinary pH. – Histopathological: increased incidence papillary necrosis in kidneys mid-dose females/ high-dose males. Increased transitional cell hyperplasia in kidneys in high-dose males. High dose: increased incidence prostatitis. |
| Knezevich & Hogan mouse n/a REVIEW RETRACTED |
EPA RED
EPA (2006) |
Increased incidence of renal tubular adenomas. EPA dismissed as “spontaneous” |
Conclusion, and PMRA Glyphosate approach – current court case
The above shows that the Williams Kroes Munro evidence on cancer was gathered and propped up by international regulatory authorities, and PMRA used it in its 2017 re-evaluation. PMRA did not independently review this evidence, and now the evidence is untenable.
PMRA was also aware of cancer risk in its “equivocal evidence” of cancer finding, but approved over it in 2017. And as we reported earlier, PMRA knows about the recently published Ramazini Global Glyphosate Study, which PROVES glyphosate actually causes cancer, but has done nothing about it.
PMRA will try to delay taking any steps on glyphosate, dismiss good studies like Ramazzini, deflect criticism, defend its approach, and deny there are any problems. Delay, dismiss, deflect, defend and deny: these are the tactics historically used by PMRA, as we well know.
Safe Food Matters sued PMRA – and is still in court – over PMRA’s 2017 re-evaluation of glyphosate. We objected that PMRA did not look at the risks associated with agricultural pre-harvest use, and did not properly apply a 10-fold safety factor for children. We lost, but won on appeal, and the Federal Court of Appeal told PMRA to follow its Guidance and re-examine our objections. PMRA dismissed them again.
And so we sued them again (with Friends of the Earth and Environmental Defence intervening), and a case schedule has been set. Laura Bowman, formerly of Ecojustice, is our counsel. Meanwhile, the US EPA has withdrawn its health risk assessment after the 9th Circuit Court of Appeals called out its unscientific cancer conclusions, and Europe has effectively banned pre-harvest use. It is a long game with PMRA, but the stakes are high – so it’s worth it.
No certainty of “no harm” – so remove glyphosate
The Minister of Health Marjorie Michel is mandated to protect Canadians from the risks of pesticides. In order for the glyphosate registration to continue, she needs evidence to show with reasonable certainty that no harm will come to Canadians from the use of glyphosate. As things currently stand, she does not have such proof when it comes to cancer- and her regulator, the PMRA, cannot provide it.
We accordingly call on the Minister of Health to remove glyphosate from use in Canada, and suggest you ask her to as well.
