Cancer: Some Notes for Activists

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Cancer: Some Notes for Activists

by David Kriebel

‘Science for the People’ Vol. 12, No. 3, May-June 1980, p. 5-7 &28

David Kriebel is a member of the St. Louis chapter of SftP, and a research associate at the Center for the Biology of Natural Systems at Washington University. His research is in occupational cancer epidemiology.  

Cancer is both a scientific and a political issue. It is a scientific issue because it is a heavily researched disease — one whose most basic characteristics are still being uncovered and one about which honest and less-than-honest differences of opinion exist among scientists. It is fundamentally a political issue because cancer is a disease with social causes, for which both the blame and the suffering are shared disproportionately by different social classes. 

This article addresses those who are confronting cancer politically: health activists, union health and safety workers, and environmentalists. Several recent developments in cancer research are relevant to the strategies pursued by anti-cancer activists. The relationship between political strategy and underlying social and biochemical conditions should be a dynamic one — strategy advancing with increased knowledge of the disease, of its causes, and of prospects for a cure. 

I will discuss four interrelated points. First, cancer, known to be an amalgam of many different diseases, must now be considered a part of the broader issue of genetic toxicology. Things that cause cancer are likely also to cause birth defects, and may cause permanent damage to human genes as well. Second, cancer’s causes are mostly environmental, but environmental causes include more than pollution, food additives, and synthetic chemicals. Third, there are natural as well as synthetic carcinogens. Fourth, preventing cancer means eliminating the carcinogens of human (mostly corporate) origin, limiting exposure to carcinogens that cannot be eliminated, and changing hazardous aspects of our lifestyles. 

The Unity of Genetic Toxicology 

Many, probably most, cancers are caused by damage to DNA, the genetic material contained in every cell1. But cancer is just one of a number of results of a mutation, as an alteration of genetic material is known. A mutation in a non-reproductive, or somatic, cell is usually lethal to that cell. Rarely, a mutation damages the cell’s normal growth and replication behavior, and a tumor can be the result. If a mutation occurs in a germ cell — a sperm, sperm-producing or egg cell — a genetic birth defect can result. If the mutation occurs in a developing fetus, particularly in the early weeks of pregnancy, a developmental birth defect can result. 

Chemicals which cause DNA damage are called mutagens. We now know that carcinogens and teratogens (substances which cause birth defects) are both mutagens. The unity of these three groups has only recently been recognized and has many important implications. All chemicals which can damage DNA must be presumed capable of causing cancer and birth defects, until proven otherwise. This view conflicts with some recent efforts by industry to remove only women from certain occupations because of risks to the fetus. Because birth defects can result from mutations in male sperm cells as well as in ovaries and the fetus, neither women nor men should be exposed to substances suspected of being teratogenic. 

In 1977, when the pesticide DBCP was found to cause infertility in male workers, the National Peach Council seriously proposed allowing only workers who wanted no more children to work with it2. This idea ignored the unity of genetic toxicology; DBCP is also a carcinogen. 

Perhaps the most frightening possibility raised by the recent research on mutagens is that of permanent effects on the entire population through genetic damage. If mutations occur in germ cells, they may be passed on to the offspring — either as obvious, often lethal birh defects, or as subtle changes in resistance to disease, physical fitness, longevity, etc., which may never be detectable, and if detected will be irreversible anyway. 

Ten years ago, a group of geneticists, biochemists and physicians had this to say about the mutagenic potential of chemicals in the environment: 

There is reason to fear that some chemicals may constitute as important a risk of human mutations as irradiation, and possibly a more serious one. Although knowledge of chemical mutagenesis in man is much less certain than that of radiation, a number of chemicals — some with widespread use — are known to induce genetic damage in some organisms. To consider only radiation hazards is to ignore what may be the submerged part of the iceberg.3 

The Ninety Percent Law 

The idea that somewhere between 75 and 90 percent of cancer is environmentally caused has been adopted by environmental health activists as their principal article of faith. Literally interpreted, this “law” is well-accepted among cancer scientists, even those employed by industry. The problem is that the meaning of “environmental cause” has been widely misconstrued. 

The studies used to estimate the environmental contribution to human cancer are simple in concept. Several scientists, notably Sir Richard Doll4, compared cancer rates in various parts of the world. His assumption was that the lowest observed rates represent genetic causes, and that all levels above that must be due to factors of the environment in which these higher rate groups live. Additionally, populations that migrate from one environment to another nearly always attain within two generations the cancer rates of the native inhabitants of their new environment5. Environment, in these studies, means everything but the anatomy and physiology of the person who develops the disease (viral causes of cancer, accounting for just a few percent of all cases, are also generally not included in the “environmental” category). This includes air and water pollution, food additives, and occupational hazards; but it also includes cigarette smoking, alcohol, sunlight, naturally occurring food-borne carcinogens, natural background radiation, and other unknown but “natural” causes.

The assumption of many activists is that pollution, synthetic chemicals, and radiation are the environmental causes, and are responsible for some 75 to 90 percent of all cancer. This is incorrect. What fraction of cancer is caused by pollution, synthetic chemicals and radiation alone? We don’t know, but it certainly is very large. A recent government study estimated that 20 percent of all cancers are probably of occupational origin.6 When we add to this all the cancers caused by air, water and land pollution; synthetic chemicals intentionally placed in the home and food; drugs; medical x-rays; and radiation from the nuclear power and nuclear weapons industries — cancers originating in human activity obviously constitute an enormous proportion of all cancers. 

Synthetic versus Natural 

Barry Commoner has for many years been reminding us that a synthetic chemical is far more likely to be harmful to us and to the environment than a naturally occurring one7. Naturally occurring chemicals have stood the test of time — they have been with us throughout our evolutionary development, and so are likely to be compatible with our physiological processes. Synthetic ones have mostly been invented or inadvertently produced only in the last few decades. They were rarely tested for compatibility with life before being mass produced. 

Not only activists, but a large part of the population, now believe that “natural” is better than synthetic. This is a good initial assumption, but is far too simple to serve as a guide for public policy. There are natural carcinogens. They cause cancer, just like the synthetic ones. Health activists often wish they would go away. They confuse things. The mold Aspergillus flavus grows on peanuts. It also produces chemicals called aflatoxins which are among the most potent chemical carcinogens known. Industry has a field day with natural carcinogens — they say things like “the risk of cancer from eating peanut butter is much greater than from eating our nitrite-treated hot dogs, so why ban the nitrite?” The science of cancer-risk estimation is so imprecise that they don’t really have a case here, but the charge certainly does confuse the issue. Environmental health activists play into the hands of their critics when they do not prepare the public for a situation more complex than “natural-good, synthetic-bad.” 

It is not at all hard to see that the existence of natural carcinogens does not justify making new ones, but on top of this, there are two important reasons for the regulation and elimination of synthetic carcinogens. As the accompanying graph (courtesy of Barry Commoner) shows, the synthetic carcinogens are being discovered far more rapidly than the natural ones. Although the data are not available, we are fairly certain that the effort spent looking for the two types has been about the same. The difference, therefore, is due to both the higher absolute number of synthetic carcinogens, and the fact that new ones are being produced all the time (some 700 new chemicals are manufactured every year 8 ). From the look of the lower curve, we do not expect to find too many more natural carcinogens. The second reason to aim the attack at the synthetics is that many of them are entirely unnecessary. As detailed elsewhere in this issue, too many synthetic chemicals are produced for their profitability, not their necessity. 

Most antinuclear activists understand that there is both natural radiation and radiation of human origin. We simply say that all radiation is bad, and even the most minute addition to our natural burden should be avoided. We note that radiation-induced leukemia has no threshold, no level of radiation so low that no leukemia risk is incurred. A similar argument must now replace the “natural-good, synthetic-bad” line on chemicals. The presence of natural carcinogens is all the more reason not to add synthetic ones to the genetic hazard. 

Blaming the Victim/Ignoring the Obvious 

The environmental carcinogens can be divided into two categories: those that we are exposed to more or less voluntarily and those that we are exposed to involuntarily. The “voluntary” exposures are sometimes called life-style factors — smoking, drinking and diet are the main ones (although a strong argument can be made for the involuntary nature of smoking and drinking, they are certainly more voluntary than water and food contaminants, air pollution, and workplace fumes). The corporate position is one which strongly stresses the voluntary risks, and minimizes the involuntary ones. In response, many environmental health activists ignore the lifestyle factors, because their political strategy targets the corporations and their pollution. Neither approach alone is correct. 

For example, tobacco smoking is a major cause of lung cancer and cancer of numerous other sites — the epidemiological and clinical studies are consistent and overwhelming9. Numerous dietary factors certainly influence cancer susceptibility, both positively and negatively10. The anti-smoking forces generally buttress their position with tables showing what percent of cancer is caused by smoking, what percent by occupation, what percent by diet, etc. The trouble with these tables is that they generally add up to 100 percent. That is, they attribute each case to a single cause. To which cause should the death of a smoking chemical worker be attributed? Usually the “smoking” category gets it. But why not attribute it to the occupation? A correct table of cancer causes would add up to more than 100 percent because of multiple causes. We currently lack the data to make such a table accurately.

Is there really a dichotomy between fighting pollution to control cancer, and changing lifestyles to control cancer? Perhaps not so much as some may think. Most activists attack the cancer-causing aspects of the production side of the capitalist economy. Air and water pollution, occupational hazards, and toxic waste dumps are all poisonous aspects of the production of goods. But as we all know, corporations only produce these goods to sell them. The consumption of these goods has cancer-causing effects too. The consumption of cigarettes, of alcohol, of overly processed food, of polluting automobiles — these are precisely the “lifestyle” issues which need changing. 

If we sincerely want to control cancer, we must address all these issues. I suggest that a broad political perspective can incorporate all the different strategies that should be pursued to control cancer. 


Cancer is just one piece of a much broader problem. Activists must understand this, and understand some of the complexities of the disease as well. The “pollution causes cancer /chemicals are bad” line is faulty and may do more harm than good. Because this has been the line, attacks like Monsanto’s “Without chemicals, life itself would be impossible” campaign can be effective. Of course there are “good” chemicals, both synthetic and natural. Of course there are “bad” natural products. Neither of these points should deflect campaigns to stop pollution, but they can if activists use an overly simplistic approach. 

Synthetic chemicals and atomic radiation of human origin represent additional mutagenic (hence carcinogenic and teratogenic) risks on top of those from natural sources. They must be controlled and, as far as possible, eliminated. Many synthetic chemicals benefit only the corporations who sell them to replace a natural substance which once did the same job — the rest of us share the costs to our health from those chemicals and their manufacture. 

People must understand that their risk of getting cancer is partly determined by other people’s decisions which they can only affect through political activity, and partly by their own actions — how they eat, whether they smoke, etc. Both of these directions can be pursued simultaneously — they need not be antagonistic. 

>> Back to Vol. 12, No. 3 <<


  1. Bruce N. Ames, “Identifying Environmental Chemicals Causing Mutations and Cancer,” Science. 204, 1979, pp. 587-593.
  2. The New York Times. September 27, 1977. 
  3. H.V. Mailing, “Chemical Mutagens as a Possible Genetic Hazard in Human Populations,” American Industrial Hygiene Association Journal. 1970, pp. 657-666.
  4. Ibid.
  5. Richard H. Doll, “Strategy for Detection of Cancer Hazards to Man,” Nature. 265, 1977, pp. 589-596.
  6. Kenneth Bridbord, et. al., “Estimates of the Fraction of Cancer in the United States Related to Occupational Factors,” Journal of the National Cancer Institute. in press.
  7. Barry Commoner, “The Promise and Perils of Petrochemicals,” New York Times Magazine. September 25, 1977.
  8. Samuel S. Epstein, “Cancer, Inflation and the Failure to Regulate,” Technology Review. December/January 1980, pp. 42-53.
  9. Smoking and Health. A Report of the Surgeon General. U.S. Department of Health, Education and Welfare, publication number PHS-79-50066, 1979.
  10. Diet. Nutrition and Cancer Program Status Report. National Cancer Institute, National Institutes of Health, 1977.