Why We Can’t Prevent Cancer

In 1999, cancer surpassed heart disease as the number one killer of people younger than 85 in the U.S.[1] Now a detailed report on the causes of cancer tells us why: cancer has been steadily increasing in the U.S. for 50 years as people have been exposed to more and more cancer-causing agents, including chemicals and radiation.

Richard Clapp, Genevieve Howe, and Molly Jacobs Lefevre have just published “Environmental and Occupational Causes of Cancer; A Review of Recent Scientific Literature” and it is a real eye-opener.

But before we dive into this report looking for nuggets, let’s set the background.

About half of all cancer cases are fatal, and death by cancer is often prolonged, painful, and very expensive. Those who manage to survive cancer live out their lives molded by the after-effects of harsh treatments popularly known as “slash and burn” — surgery, chemotherapy, radiation, or some combination of the three.

As more people are kept alive each year with their breasts or testicles removed, the “cancer establishment” chalks up another “victory” — and no doubt the victims are glad to be alive — but we should acknowledge that there’s something very wrong with calling this “victory.” Slash and burn seems more like a dreadful defeat.

The truth is, an epic struggle has been going on for 50 years between the “slash and burn=victory” camp, versus those who think the only real victory is prevention of disease. The struggle occurs across a fault line defined by money. To be blunt about it, there’s no money in prevention, and once you’ve got cancer you’ll pay anything to try to stay alive. Cancer treatment is therefore a booming business, and cancer prevention is nowhere. That is the basic dynamic of the debate. Cancer surgeons can achieve the status of rock stars among their peers. Those who advocate prevention will most likely find themselves without funding, ridiculed and despised by the chemical industry, the pesticide industry, the asbestos industry, the oil industry and all their minions — lawyers, bankers, engineers, reporters, professors, and politicians — who make a fat living off those who pump out cancer-causing products and dump out cancer-causing by-products, aka toxic waste.

The debate began 50 years ago when a powerful voice for prevention spoke out from inside the National Cancer Institute (NCI). In 1948. Wilhelm Hueper, a senior NCI scientist, wrote,

“Environmental carcinogenesis is the newest and one of the most ominous of the end-products of our industrial environment. Though its full scope and extent are still unknown, because it is so new and because the facts are so extremely difficult to obtain, enough is known to make it obvious that extrinsic [outside-the-body] carcinogens present a very immediate and pressing problem in public and individual health.”

In 1964, Hueper and his NCI colleague, W. C. Conway, described patterns in cancer incidence as “an epidemic in slow motion”:

“Through a continued, unrestrained, needless, avoidable and, in part reckless increasing contamination of the human environment with chemical and physical carcinogens and with chemicals supporting and potentiating their action, the stage is being set indeed for a future occurrence of an acute, catastrophic epidemic, which once present cannot effectively be checked for several decades with the means available nor can its course appreciably be altered once it has been set in motion,” they wrote.[pg. 28]

Hueper of course was right. This is why 50% of all men and 40% of all women in the U.S. now hear the chilling words, “You’ve got cancer” at some point in their lives. That’s right, 1 out of every 2 men now get cancer in the U.S., and more than 1 out of every 3 women.

Clapp, Howe and Lefevre tell us that between 1950 and 2001 the incidence rate for all types of cancer increased 85%, using age-adjusted data, which means cancer isn’t increasing because people are living longer. People are getting more cancer because they’re exposed to more cancer-causing agents.

Contrary to well-funded rumors, the culprit isn’t just tobacco or the hundreds of toxic chemicals intentionally added to tobacco products. Tobacco products remain the single most significant preventable cause of cancer, but they have not been linked to the majority of cancers nor to many of the cancers that have increased most rapidly in recent decades including melanoma, lymphomas, testicular, brain, and bone marrow cancers.[pg. 1]

No, it’s more complicated than just tobacco with its toxic additives. Most plastics, detergents, solvents, and pesticides and the toxic-waste by-products of their manufacture came into being after World War II. From the late 1950s to the late 1990s, we disposed of more than 750 million tons of toxic chemical wastes.[pg. 27] Over 40 years, this represents more than two tons of toxic chemical wastes discharged into the environment for each man, woman and child in the U.S. No wonder some of it has come back to bite us.

Since the U.S. EPA began its Toxics Release Inventory (TRI) program in 1987, total releases have been reported as declining (though EPA does not check the accuracy of industry’s self-reporting). Despite the reported decline, in 2002, the most recent year reported, 24,379 facilities in the U.S. reported releasing 4.79 billion pounds of over 650 different chemicals. (And TRI data do not include other enormous discharges: toxic vehicle emissions, the majority of releases of pesticides, volatile organic compounds, and fertilizers, or releases from numerous other non-industrial sources.) In 2001, more than 1.2 billion pounds of pesticides were intentionally discharged into the environment in the United States and over 5.0 billion pounds in the whole world.[pg. 27]

While all this chemical dumping has been going on, incidence rates for some cancer sites have increased particularly rapidly over the past half century. From 1950-2001, melanoma of the skin increased by 690%, female lung & bronchial cancer increased by 685%, prostate cancer by 286%, myeloma by 273%, thyroid cancer by 258%, non-Hodgkin’s lymphoma by 249%, liver and intrahepatic duct cancer by 234%, male lung & bronchial cancer by 204%, kidney and renal pelvis cancers by 182%, testicular cancer by 143%, brain and other nervous system cancers by 136%, bladder cancer by 97%, female breast cancer by 90%, and cancer in all sites by 86%.[pg. 25]

In the most recent 10-year period for which we have data (1992-2001), liver cancer increased by 39%, thyroid cancer increased by 36%, melanoma increased by 26%, soft tissue sarcomas (including heart) by 15%, kidney and renal pelvis cancers by 12%, and testicular cancer increased by 4%.[pg. 25]

OK, so dumping chemicals into the environment has been a major industrial pastime for 50 years, and cancers are increasing. But why do we think these things are connected? What real evidence do we have that environmental and occupational exposures contribute to cancer?

That’s what the new Clapp-Howe-Lefevre report is about. It is a review of recent scientific literature — with emphasis on human studies, not studies of laboratory animals. Indeed, the bulk of the new Clapp-Howe-Lefevre report is a cancer-by-cancer compendium of what recent human studies tell us about environmental and occupational exposures that contribute to cancers of the bladder, bone, brain, breast, cervix, colon, lymph nodes (Hodgkin’s disease and non- Hodgkin’s lymphoma), kidney, larynx, liver and bile ducts, lungs, nasal passages, ovaries, pancreas, prostate, rectum, soft tissues (soft tissue sarcoma), skin, stomach, testicles, and thyroid, plus leukemia, mesothelioma, and multiple myeloma. (It is worth pointing out — and Clapp-Howe-Lefevre do point it out — that this compendium owes a great debt to a data spreadsheet on cancer and its environmental causes prepared by Sarah Janssen, Gina Solomon and Ted Schettler, for which thanks are due the Collaborative on Health and Environment.)

Many of the bad actor chemicals are well-known to us all: metals and metallic dusts (arsenic, lead, mercury, cadmium, hexavalent chromium, nickel); solvents (benzene, carbon tet, TCE, PCE, xylene, toluene, among others); aromatic amines; petrochemicals and combustion byproducts (polycyclic aromatic hydrocarbons, or PAHs); diesel exhaust; ionizing radiation (x-rays, for example); non-ionizing radiation (magnetic fields, radio waves); metalworking fluids and mineral oils; pesticides; N-nitroso compounds; hormone-disrupting chemicals (found in many pesticides, fuels, plastics, detergents, and prescription drugs); chlorination byproducts in drinking water; natural fibers (asbestos, silica, wood dust); man-made fibers (fiber glass, rock wool, ceramic fibers); reactive chemicals (such as sulfuric acids, vinyl chloride monomer, and many others); petroleum products; PCBs; dioxins; mustard gas; aromatic amines; environmental tobacco smoke; and outdoor air pollution.

But there is additional evidence linking chemicals with cancer:

* Elevated cancer rates follow patterns — the disease is more common in cities, in farming states, near hazardous waste sites, downwind of certain industrial activities, and around certain drinking-water wells. Patterns of elevated cancer incidence and mortality have been linked to areas of pesticide use, toxic work exposures, hazardous waste incinerators, and other sources of pollution.[pg. 26]

* The U.S. EPA’s long-delayed and heavily industry-influenced “Draft Dioxin Reassessment” released in 2000 admitted that the weight of the evidence from human studies suggests that, “the generally increased risk of overall cancer is more likely than not due to exposure to TCDD [dioxin] and its congeners [chemical relatives].” The report goes on to conclude, “The consistency of this finding in the four major cohort studies and the Seveso victims is corroborated by animal studies that show TCDD to be a multisite, multisex, and multispecies carcinogen with a mechanistic basis.”[pg. 26]

* Farmers in industrialized nations die more often than the rest of us from multiple myeloma, melanoma, prostate cancer, Hodgkin’s lymphoma, leukemia, and cancers of the lip and stomach. They have higher rates of non-Hodgkin’s lymphoma and brain cancer. Migrant farmers experience elevated rates of multiple myeloma as well as cancers of the stomach, prostate, and testicles.[pg. 26]

* The growing burden of cancer on children provides some of the most convincing evidence of the role of environmental and occupational exposures in causing cancers. Children do not smoke, drink alcohol, or hold stressful jobs. Their lifestyles have not changed appreciably in recent years. In proportion to their body weight, however, “children drink 2.5 times more water, eat 3 to 4 times more food, and breathe 2 times more air” than adults.” In addition, their developing bodies may well be affected by parental exposures prior to conception, exposures while growing in the uterus, and the contents of breast milk.

Clapp-Howe-Lefevre put it this way:

“We have learned how to save more lives, thankfully, but more children are still diagnosed with cancer every year. The incidence of cancer in all sites combined among children ages 0-19 increased by 22% from 13.8/100,000 in 1973 to 16.8 in 2000 and most of this increase occurred in the 1970s and 1980s. Epidemiologic studies have consistently linked higher risks of childhood leukemia and childhood brain and central nervous system cancers with parental and childhood exposure to particular toxic chemicals including solvents, pesticides, petrochemicals, and certain industrial by-products (namely dioxins and polycyclic aromatic hydrocarbons [PAHs]).”[pg. 26]

All in all, the Clapp-Howe-Lefevre report makes a compelling case that many industrial chemicals contribute to many kinds of cancers. But where this report really shines is in its clear call for prevention. In all, there are relatively few products or substances associated with cancer.[pgs. 10-11, 37-40] Everything doesn’t cause cancer, and many of the things that do could be shunned and phased out. In principle, a great deal of prevention is possible.

Thirty years into the prevention-vs-treatment debate — in 1981 — two famous British scientists — Sir Richard Doll and Sir Richard Peto — published an extremely influential study in which they estimated that “only” 2 to 4% of all cancers are caused by environmental or workplace exposures. With 1.2 million new cases of cancer each year in the U.S., half of them fatal, 2% to 4% = 12,000 to 24,000 deaths each year, most of them preventable. Doll and Peto said tobacco caused 30% of all cancers and food caused another 35%. We now know that cancer results from the interaction of our genes with exposure to several cancer-causing agents. All the necessary exposures must occur to cause a cancer — if any one of them is missing, the cancer will not occur. This is why prevention is important — it really can work.

Because cancer requires multiple exposures to cancer-causing agents, it is wrong and misleading to say that “Exposure to product A causes X percent of all cancers.” It simple doesn’t work like that. Perhaps Doll and Peto in 1981 did not know how such things worked, and they boldly proceeded to estimate what percent of all cancers were attributable to particular exposures. It was wrong, but their report served as powerful ammunition for the prevention-is-pointless crowd. If “only” 2 to 4% of all cancers were caused by environmental exposures, then there was little incentive to prevent human exposure to environmental agents, the argument went. What a welcome message this was for the cancer-creation industries (petrochemicals, metals, pesticides, asbestos, radiation, and others) and for the cancer treatment industry! Damn the torpedoes — full speed ahead!

The prevention-is-pointless crowd latched onto the Doll and Peto study and spread it everywhere. By the end of 2004, the original 1981 Doll-and-Peto paper had been cited in 441 subsequent scientific papers.[pg. 4] But even more importantly, the federal National Cancer Institute and the American Cancer Society (which, together, you could call the “cancer establishment”) adopted the Doll-Peto perspective, that cancer is a lifestyle disease — the victims themselves are responsible — and that prevention of environmental and occupational exposures is not worth the effort. Remember this was the beginning of the Reagan counterrevolution and the Doll-Peto paper fit right into the new ideology — government is bad, big corporations are good, we’re all individually responsible for whatever bad things happen to us, and greed is good because it makes the world go ’round. In any case, the NCI and the ACS largely adopted the Doll-Peto perspective, and they poured the bucks into new cancer treatments, pretty much ignoring prevention. Meanwhile, cancer incidence rates climbed relentlessly — making the cancer-treatment industry healthier and wealthier, which allowed it to further erode support for prevention.

Now we are starting to shake off the stupor induced by the misleading Doll-Peto arithmetic, which pretended to prove that environment and occupational exposures are of no consequence.

Listen to this marvelously clear-eyed conclusion from the Clapp-Howe-Lefevre report:

“Comprehensive cancer prevention programs need to reduce exposures from all avoidable sources. Cancer prevention programs focused on tobacco use, diet, and other individual behaviors disregard the lessons of science.”[pg. 1]

And this:

“Preventing carcinogenic exposures wherever possible should be the goal and comprehensive cancer prevention programs should aim to reduce exposures from all avoidable sources, including environmental and occupational sources.”[pg. 6]

And this:

“Further research is needed, but we will never be able to study and draw conclusions about the potential interactions of exposure to every possible combination of the nearly 100,000 synthetic chemicals in use today. Despite the small increased risk of developing cancer following a single exposure to an environmental carcinogen, the number of cancer cases that might be caused by environmental carcinogens is likely quite large due to the ubiquity [presence everywhere] of carcinogens. Thus, the need to limit exposures to environmental and occupational carcinogens is urgent.”[pg. 29]

And this:

“The sum of the evidence regarding environmental and occupational contributions to cancer justifies urgent acceleration of policy efforts to prevent carcinogenic exposures. By implementing precautionary policies, Europeans are creating a model that can be applied in the U.S. to protect public health and the environment. To ignore the scientific evidence is to knowingly permit tens of thousands of unnecessary illnesses and deaths each year.”[pg. 1]

What a blast of fresh air!

The latest strategy from the cancer-creation industries is to claim that we can’t take action to prevent environmental and occupational exposures because we don’t have enough information. We’re simply too ignorant to make a move. More study is needed. Clapp-Howe-Lefevre allow the eloquent writer Sandra Steingraber to answer this argument. They say, “A main concern for Sandra Steingraber, author of Living Downstream: An Ecologist Looks at Cancer and the Environment, is not whether the greatest dangers are presented by dump sites, workplace exposures, drinking water, food, or air emissions:

“I am more concerned [writes Steingraber] that the uncertainty over details is being used to call into doubt the fact that profound connections do exist between human health and the environment. I am more concerned that uncertainty is too often parlayed into an excuse to do nothing until more research can be conducted.”[pg. 29]

Clapp, Howe and Lefevre go on: “At the same time, uncertainty and controversy are permanent players in scientific research. However, they must not deter us from enacting regulations and policies based on what we know and pursuing the wisdom of the precautionary principle. This is not new thinking, as demonstrated by Sir Austin Bradford Hill’s 1965 address to the Royal Society of Medicine:

“All scientific work is incomplete [wrote Sir Austin Bradford Hill] — whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have, or to postpone action that it appears to demand at a given time.”[pg. 29]

Clapp, Howe and Lefevre then offer some guidelines for preventive action:

(1) The least toxic alternatives should always be used.

(2) Partial, but reliable, evidence of harm should compel us to act on the side of caution to prevent needless sickness and death.

(3) The right of people to know what they are being exposed to must be protected.

Clapp, Howe and Lefevre observe that “the United States has much to learn” from the proposed European chemicals policy, known as REACH:

(1) requiring that industry be responsible for generating information on chemicals, for evaluating risks, and for assuring safety; another way of saying this is, “No data, no market.”

(2) extending responsibility for testing and management to the entire manufacturing chain — everyone who uses a chemical has a duty to familiarize themselves with the consequences;

(3) using safer substitutes for chemicals of high concern; and,

(4) encouraging innovation in safer substitutes.[pg. 29]

In the words of ecologist Sandra Steingraber: “It is time to start pursuing alternative paths. From the right to know and the duty to inquire flows the obligation to act.”[pg. 29]

But while we’re working in clear-eyed mode here, let’s take our exploration a bit further and look this problem squarely in the face.

The U.S. economy and culture are premised on endless growth. If I loan you $100 in the expectation that you will pay me back $103 next year, that extra 3% must come from somewhere. That “somewhere” has physical dimensions — something must be dug up or grown to produce the additional 3%. That something must also be moved, processed, moved again, packaged, promoted and sold, moved again, used, moved again, and eventually discarded. Even if it is recycled many times, ultimately it will be discarded into a natural ecosystem somewhere (at which point nature begins moving it once again). The inescapable second law of thermodynamics tells us that each of these steps will inevitably be accompanied by waste, disorder and other disruptive unintended consequences. Even if you create the extra 3% per year by providing a “service” instead of a “product,” you still require food, water, shelter, energy, clothing, tools, transportation, commercial space, medical care, municipal support services (like police, fire, emergency services, and sewage treatment), leisure activities, communications and information, schooling, and on and on.

An economy that is growing at 3% per year is doubling in size every 23 years — requiring, every 23 years, a doubling in the number of cities, food sources, mines, factories, power plants, vehicles, highways, parking lots, schools, sewage treatment plants, hospitals, prisons, discards, trash and dumps. For a very long time this kind of rapid growth seemed tolerable. But now things are different — the earth is full of people and their artifacts. We can no longer throw things “away” without affecting someone somewhere.

Something else is new as well. The modern, globalized financial environment (in which money flows easily across international borders), creates tremendous competitive pressure to attract investment by increasing return to investors. That in turn creates pressure to pass costs along to the general public. Economists call it “externalizing” costs. If I dump my chemicals and make you sick, I gain if I can get you to pay your own medical bills, and I gain again if I can get taxpayers to clean up my mess. Firms have a natural incentive to externalize their costs to the extent possible, but the present “globalized” financial environment has increased that incentive greatly, to improve return to investors.

In sum, let us review the pressures that prevent prevention.

(1) In general, it is difficult to make prevention pay, but remediation can pay handsomely; this is certainly true for the cancer industry. In general, financial-political-legal incentives are set up to reward those who create problems and those who supply remedies.

(2) Economic growth entails the continual creation of ever-more and ever-larger messes. Even if we managed to “green” commerce in every way we can think of today, damage to nature would still be roughly proportional to the size of the human economy because the second law of thermodynamics cannot be evaded. And we now know that damage to nature gives rise to human disease in myriad ways. Now that the earth is full, a growing economy creates palpably-growing health problems, including immune system degradation giving rise to cancers.

(3) The modern economy creates irresistible pressure to increase stock prices, which in turn creates relentless pressure to externalize costs by hook or by crook.

So let’s not kid ourselves. Yes, cancer must be prevented because for the most part it can’t be cured — it can only be slashed and burned away at enormous cost, personal, social and monetary.

But saying cancer must be prevented is one thing. Expecting that it can be prevented within the framework of the modern economy is another. We can never stop working to prevent cancer — and precautionary policies will always make sense no matter what kind of economy we have — but until we shift to an economy that doesn’t require growth, we’ll find ourselves right where we are now — on an accelerating rat wheel. As a result, we can expect to be living with more and more cancer at greater and greater cost to ourselves and to our children, accompanied by ever-increasing pain. It is not a pretty picture. But at least we can now see it clearly.


[1] Richard Clapp, Genevieve Howe, and Molly Jacobs Lefevre, Environmental and Occupational Causes of Cancer; A Review of Recent Scientific Literature (Lowell, Mass.: University of Massachusetts at Lowell, The Lowell Center for Sustainable Production, September, 2005. Unless otherwise noted, throughout this issue of Rachel’s, footnote numbers inside square brackets refer to pages in this report.

PETER MONTAGUE is editor of the indispensable Rachel’s Health and Democracy, where this essay originally appeared. He can be reached at: peter@rachel.org



Peter Montague is a fellow with the Science & Environmental Health Network, living in New Jersey.