By André Leu
The recent verdict awarding Dewayne Johnson $289 million, because a jury determined that glyphosate, the active ingredient in Roundup, caused his non-Hodgkin lymphoma cancer, will open the floodgates for thousands of more people suing the manufacturer, Monsanto/Bayer.
The World Health Organization’s International Agency for Research on Cancer (IARC) gave glyphosate the second-highest classification for cancer: 2A, a probable human carcinogen, in 2015. This means that cancer has been found in test animals, with limited evidence in humans. The evidence in humans was a strong association with non-Hodgkin lymphoma.
Despite this, the manufacturer continues to state that its studies and the reviews by regulators show that glyphosate does not cause cancer. The manufacturer and regulators, like the U.S. EPA, will not produce these safety studies, to be reviewed by independent scientists and other stakeholders, as they are considered commercial in confidence.
The first issue here is if they have the evidence that glyphosate does not cause cancer, why don’t they publicly release it, rather than hiding it?
The other major issue of concern is that the current best practice testing guidelines for pesticides miss the majority of cancers.
The testing guidelines for the Organisation for Economic Co-operation and Development (OECD) are regarded as best practice for testing animals for diseases caused by chemicals such as pesticides and are similar to most good practice testing guidelines.
Guideline 451 of the OECD is used for the experimental design of testing chemicals, such as pesticides, for cancers. It requires that: “Each dose group and concurrent control group should therefore contain at least 50 animals of each sex.” This is a group of 100 animals, with an equal amount of males and females. The guidelines also state: “At least three dose levels and a concurrent control should be used.”
This means that there must be one group of 100 animals, usually rats, that are the control and are not dosed with the chemical. There will be three other groups of 100 rats in each group given a dosage of the chemical from highest, middle, to lowest. The number of cancers in each of the dosed groups is compared with the number of cancers in the control group of rats. If the number of cancers is the same between the treated group and the control, then it is considered that the cancers were not caused by the chemical, but by some other means, as the control has not been exposed to the chemical. This is then used to say that a chemical or pesticide does not cause cancer.
There are serious flaws in this method. One of the dosed groups of animals with just one extra cancer than the control results in 1 animal in 100 with cancer. This is the lowest theoretical rate of detection, and it means that cancer would only be detected if the pesticide caused more than 1,000 people per 100,000 people to get cancer. It would miss lower rates of cancer, which are the actual rates of cancers.
The rates of diseases are categorized by the number of people with the disease per 100,000 people. According to the Centers for Disease Control and Prevention (CDC), in the United States, the rates of common cancers such as lung cancer are 57.5 people per 100,000; colon and rectum cancer 38 per 100,000; non-Hodgkin lymphoma 18.4 per 100,000; leukemias 13.2 per 100,000; pancreatic cancer 12.8 per 100,000; and liver and intrahepatic bile duct cancers 8.3 per 100,000.
For sex-dependent cancers such as breast, ovarian, endometrial, prostate and testicular cancers, the lowest theoretical level of detection is 1 animal in 50 because there are 50 animals of each sex. This means that these cancers would only be detected if they cause more than 2,000 cases of cancer per 100,000 people.
Consequently, despite no evidence of cancer being found in the dosed groups, the study would miss a chemical that could be causing the current epidemic of cancers of sexual tissues. According to the CDC, in 2015 the rate of breast cancer was 124.8 women per 100,000; prostate cancer was 99.1 men per 100,000; ovarian cancer was 11 per 100,000; cancer of the cervix 7.6 per 100,000; and testicular cancer 5.6 per 100,000.
There is no statistically valid way to determine that a dosed group of 100 animals, that shows no sign of cancer, can determine that the chemical in question cannot cause cancer at rates below 1,000 people per 100,000. All of the current cancers found in our communities will be missed.
The only way this could be done statistically would be to have greater amounts of test animals.
The fact is that studies using OECD or similar guidelines, that do not find cancer, cannot accurately say that a chemical does not cause cancer, as they would miss all known cancers.
The Glyphosate Debate
The WHO decision and the Dewayne Johnson verdict agreed that glyphosate is linked to non-Hodgkin lymphoma. The manufacturer states that it does cause this or any other cancer.
The published studies on glyphosate (and other pesticides), even if they used OECD or similar guidelines, use numbers of animals that are too small to detect any of the current cancers and therefore there is no basis to say that it does not cause cancer. It is statistically impossible to use a testing methodology that can only detect cancers to a minimum level of 1,000 cancers per 100,000 people to detect common cancers like lung cancer that occurs at rates of 57.5 people per 100,000 down to liver cancer at rates of 8.3 people 100,000.
Non-Hodgkin lymphoma affects 18.4 people per 100,000 in the United States. To positively determine if glyphosate does not cause this cancer an experiment would need a control group of 100,000 rats along with three dose groups of 100,000 rats each — 400,000 rats total. If this experiment showed no sign of non-Hodgkin lymphoma, then it would be statistically probable that it did not contribute to the 18.4 people per 100,000 with the disease. However as far as I know, no such experiment has ever been done.
The fact is that the current testing protocols can only tell us if a pesticide causes cancer. It cannot tell us if a pesticide is safe. Finding no evidence of cancer in a study is not the same as saying that the chemical in question does not cause cancer.
In my opinion it is a gross misrepresentation to say that any of the current published toxicology studies can be used to say that any of the thousands of pesticide products used in the world do not cause cancer and are safe, including glyphosate.