|PESTICIDES AND CANCER
An edited transcript of a lecture given by Professor Samuel Epstein, 1993. He is Professor of Occupational and Environmental Medicine at the School of Public Health, University of Illinois, California.
A Sheffield farmer who is campaigning against diazinon, a compound of sheep dip, because of neurobehavioural problems in both sheep and farmers, was assured by the Ministry of Health that there is no basis for linking such problems with this particular organophosphate.
This official denial of any link reflects both an ignorance of the literature, and an automatic reflex denial on problems of causation. There is, in fact, a substantive literature on neurobehavioural effects of organophosphates in general, and diazinon in particular.
Cancer treatment is at times damaging
While the cancer rate is increasing, our ability to treat and cure cancer has not materially improved for decades. Although there have been remarkable successes with some of the rare cancers, childhood cancers, some lymphomas and testicular cancer, some of these successes may be more apparent than real.
For instance, children who have been treated successfully for acute leukaemia with anti-metabolites - 6-mercaptopurine among others - have a 10 to 20-fold greater chance of getting subsequent cancers from the treatment itself. In addition, there's a wide range of other delayed toxic effects.
When you examine most cancers for which chemotherapy is used, namely cancers of epithelial organs such as breast, gut etc., once they are past the localised stage there is no evidence that chemotherapy is of any value, despite contrary assertions by the cancer establishments in New Zealand, Britain and the USA. Some data indicate that people who leave the cancer untreated do better, because treatment in many instances is so toxic that it not only damages the quality of life but also shortens life.
This contrasts with the hyperoptimistic claims periodically made, the basis for which is usually what is known as initial tumour response, a shrinkage of the tumour. A 75% shrinkage in tumour size is hailed as the latest cure. But such "cured" patients live no longer than those who were not treated at all, and in fact often die earlier.
Another factor is massive permeation of our air, food and water and workplace with synthetic carcinogens over the last few decades. The US began manufacturing synthetic organic chemicals in 1940, and by the mid-1980s about 5 billion pounds were being produced annually. Amongst the major classes of these chemicals are pesticides.
It is difficult to interest the average person in the issue of pesticides until you point out that:-
For the chronic neurobehavioural problems which we're seeing increasingly in people who have been exposed to organophosphates, we don't have a national database. So when industry asks where the epidemiological evidence is, the answer is that, with the exception of cancer, we don't have any registry on most other chronic diseases from immunological to reproductive, although one or two countries have registers for birth defects.
Furthermore, most carcinogens also induce other chronic toxic effects. The "average" carcinogen not only produces cancer, it also inhibits immune response and can be reproductively toxic. So, from the point of view of human impact, cancer is the most important expression of the new petrochemical era, the runaway technology of the twentieth century.
Evidence on the carcinogenicity of pesticides goes back for decades, with overwhelming data from animal experiments that have been repeated ad nauseam nationally and internationally. There's a consensus that a chemical that has been shown to be carcinogenic in animal tests must also be carcinogenic in humans.
A reason why we don't have epidemiological data on a wide range of industrial chemicals, including pesticides, is that the industries concerned have created impediments and blocks to the development of such data. That's another big topic on its own.
Over and above the experimental data from animal tests, we have studies from farmers all over the world showing major increases in overall cancer rates - a wide range of cancers including Non-Hodgkin's Lymphoma, soft-tissue sarcoma, leukaemias, multiple myelomas. Rates of increase in leukaemias and multiple myelomas in the US over the last few decades are in excess of 100%.
As regards the nature of exposure of the individual householder or citizen to pesticides, and evidence linking their exposure to cancer, we know there is massive drift when pesticides are applied, particularly from aerial application. In general, less than 5% applied aerially reaches the target. It's a substantial drift and it can happen not only from aerial application but also from urban mosquito control programmes and lawn spraying.
Of about 35 chemicals used as pesticides in lawn spraying in this country, as in the US, some are unequivocal carcinogens, including 2,4-D; 10 are reproductive toxins, and 14-15 are known to be immunotoxic, etc.
Additional lines of evidence come from what we call "risk assessments" of dietary contaminants. We know that foodstuffs are contaminated with a very wide range of carcinogenic pesticides. Very limited data are available in this country, but according to the last data from the Ministry of Health and MAF, celery has in the region of 17 pesticide residues, about 10 of which are carcinogenic, and an apple may have as many as 5-10 carcinogenic pesticides, so you're dealing with food which has massive and pervasive contamination.
The EPA under the Reagan/Bush administration wasn't exactly a progressive organisation. In fact, amongst the crimes of Reagan and Bush which will go down in history are their emasculation of Federal regulatory apparatus, with the appointment of chiefs and heads of Federal agencies hostile to the legislative mandates.
The Dellaney Amendment was a 1958 law, an amendment to the Federal Food, Drug and Cosmetic Act which basically says, "Thou shalt not add any level of carcinogenic pesticides to the foodstuffs". This was an important law because it recognised that we don't know any way of stating safe levels of carcinogens; and it also insulated the Federal agencies EPA and FDA from political pressures from the chemical industry etc. But in 1988, under the Bush administration, the EPA - illegally, in our view - revoked the Dellaney Law and introduced the concept of "acceptable risk". This allows one pesticide on one particular food item if the risk for that is no more than one in a hundred thousand cancers per year. This is based on attempts to extrapolate from animal data. There are problems in that these numbers are highly relaxed in terms of protecting the public. The EPA permissible level translates nationally to 30-40 extra cancer deaths per year.
However, if you take the more realistic position that we eat many food items in a meal, and every one might be contaminated by 5 to 10 to 15 different pesticides, then according to the Reagan/Bush data, the figures for aggregate risk come to about 50-60,000 extra cancer deaths a year.
Among many other lines of evidence, one that relates to dogs is quite interesting. Dog owners who have had their lawns treated with a chemical will find that their dogs will die, at a six times greater rate than others, of a variety of problems, particularly Non-Hodgkin's Lymphoma.
In many instances, the American Cancer Society has demonstrated actual hostility to prevention. For example, they refused to support toxic substances legislation, they refused to support the Dellaney Law, which forbids the actual and deliberate addition of chemical carcinogens to foodstuffs. There's a long track record of these acts of indifference.
For these reasons, I and others have come to the conclusion that the only way of persuading the American Cancer Society to develop more responsible policies is to threaten them with an economic boycott. In fact, a variety of groups all over the US, particularly women's breast cancer groups, are in the process of organising such a boycott.
Breast cancer is a subject that is creating a great deal of interest in the US, Britain and New Zealand. Rates of breast cancer have increased from the 1950s to the mid-1980s by almost 60%.
The established risk factors for breast cancer include genetic, familial factors; they also include reproductive factors: late menstruation, late menopause, no children, and a so-called high-fat diet. The National Cancer Institute and the American Cancer Society have spent $1.5 billion in the last two decades on cancer research that focuses mainly on nutritional factors; and they still claim that a high fat diet itself is an important risk factor.
Well, a series of epidemiological studies - what we call case control in cobalt studies - have clearly shown no link between breast cancer and a high fat diet itself. So these risk factors can only account for about 20% of all breast cancers, and they can in no way account for increase in incidence and increase in mortality from breast cancer over the last few decades.
The intriguing point about all the nutritional studies from the American Cancer Society and the National Cancer Institute, in this country and elsewhere, is that none of these studies has looked into the question of dietary contaminants. None at all. Yet when you look into the matter of dietary contaminants, a wide range of lines of evidence become apparent, which create a very strong presumption of causal relationship between contaminants and breast cancer.
First, the carcinogenicity of the organochlorine pesticides DDT, aldrin, dieldrin, chlor, heptachlorine etc. has been known since the late 1960s. Furthermore, the three major studies made so far of women with breast cancer have all shown excess of these organochlorines, and also PCBs, in breasts with cancer as opposed to those without cancer.
Then we have the "Israel Anomaly". In the mid-1970s the Israeli Ministry of Health forced major reduction in levels of organochlorine pesticide residue contaminants in dairy products and related foods, and what we then saw was a major decrease, by 30%, in premenopausal mortality from breast cancer. This was a unique phenomenon; especially since at that time reproductive risk factors were increasing: women were having fewer children and they were eating more fat, and yet this occurred.
Who is responsible?
Probably the greatest responsibility for the cancer epidemic we're faced with lies with you. Your lack of interest in the past, your lack of involvement, your unwillingness to develop coherent strategies, your unwillingness to challenge authority - these have created a vacuum in decision-making, that has been filled by professional groups with mindsets, with conflicts of interests, in some instances with close relationships with the chemical industries - professional groups that are uninterested in prevention. By your quiescence and your acquiescence, you have allowed these situations to develop. I think the responsibility for the cancer epidemic is reflected in the Pogo cartoon: "I see the enemy, and the enemy is us". It is high time that empowerment and democracy and decision-making on these vital issues should be at least shared by you, if you should not indeed take a more prominent role.