Volume 6, Number 7

CANCER AND HEALTH: TV Attention to the Environmental Causes of Cancer

CANCER KILLS OVER 50,000 CANADIANS EACH YEAR. The majority of these deaths occur in people over age 70. However, cancer is not just a disease of the elderly; it is the leading cause of death for women aged 20 to 44, accounting for over 1,000 deaths in Canada each year.

Given these sobering facts, it is vital that the public be informed about what causes cancer. A Gallup poll conducted for the Canadian Cancer Society discovered that: "Cancer is seen as having an unknown cause; as being a powerful disease with a mysterious course of its own, controlled by fate and not by its victim nor the medical profession." The poll also found that most people believe that cancer is the leading cause of death even though cardiovascular disease is actually the number one killer in Canada. [Birdsell, J. M. et al (1990), Preventing Cancer in Alberta: Challenges and Opportunities, Alberta Cancer Board, Division of Epidemiology and Preventive Oncology, p. 6.]

Most disturbingly, Canadians believe that the causes of cancer are unknown. According to most scientists, cancer is usually caused by such mundane things as eating too much and smoking. Professor Christine Poulin of Dalhousie University states: "Preventing cancer largely entails adopting healthy behaviours, such as eating a low-fat diet, [and] not smoking. . . . The challenge for cancer prevention is finding out why people behave the way they do, what encourages them to adopt and maintain healthy behaviours, and what hampers them from doing do."

As the information provided on the nightly television newscasts have been shown to influence people's behaviour, this On Balance will analyze television's attention to the causes of cancer over the past five years. Does the television coverage support or contradict the widely held belief that the causes of cancer are unknown? Is the onus for preventing cancer placed on the individual, the government or industry? And do the television reports allow the public to make informed decisions which will allow them to reduce their risk of getting cancer?

Environmental Factors Depicted as Primary Cause of Cancer

CANCER IS THE TERM FOR A PROCESS OF abnormal cell division which spreads throughout the body, invading and destroying normal tissue. While scientists do not understand why this process occurs, decades of research have determined the principal causes of cancer. Dr. Robert Scheuplein, head of the Food and Drug Administration's Office of Toxicology, states: "There are essentially three causes of cancer--to the extent that they can be separated . . . tobacco or cigarettes would account for one-third of all cancers; diet would be one-third; and everything else would be the other third."

This is a simplification of the factors which have been linked to cancer, but is useful for analytical purposes. As shown in Figure A, the risks associated with diet and smoking were virtually ignored by the national television networks. Instead, CBC and CTV focused on the environmental causes of cancer. Two-thirds of CBC and over one-half of CTV attention to all causes of cancer focused on environmental factors.

Click here to view Figure A: TV's Focus on the Causes of Cancer

The environmental factors being blamed for cancer were pesticides, man made chemicals, man made radiation, asbestos, general pollution, ozone depletion as a result of CFCs and magnetic fields--all by-products of the modern industrial world (see figure B). However, in a widely-cited paper, Oxford researchers Doll and Peto found that the best estimate for pollution and industrial products as a cause of cancer deaths was less than 3 percent. [Doll, R., and Peto, R. (1981). "Quantitative estimates of avoidable risks of cancer in the United States today," The Causes of Cancer, Oxford University Press: Oxford, New York.]

Click here to view Figure B: Attention to the Environmental Causes of Cancer

The Alberta Cancer Board agreed with this analysis. In its recent book, a chapter entitled "Can Cancer Deaths Be Avoided?" stated: "There is no current evidence to suggest that environmental factors play a major role in cancer causation." [Birdsell, J.M. et al, (1990), Preventing Cancer in Alberta: Challenges and Opportunities, Alberta Cancer Board, Division of Epidemiology and Preventive Oncology, p. 48.] Yet, with the greatest portion of television coverage focusing on the environment as a cause of cancer, the public is being led to believe that these factors pose a serious health risk.

Individual responsibility ignored by networks

The television reports consistently ignored the causes of cancer which are within the control of the individual. Diet, alcohol, tobacco and sun tanning constituted only 15 percent of CBC and 25 percent of CTV total attention to the causes of cancer. Yet, it is estimated that these factors cause almost three-quarters of cancer deaths.

. . . the risks associated with diet and smoking were virtually ignored by the national television networks. Instead, CBC and CTV focused on the environmental causes of cancer. Two-thirds of CBC and over one-half of CTV attention to all causes of cancer focused on environmental factors.

In contrast, the environmental causes of cancer, which are primarily factors beyond the control of the individual, such as pollution and food contaminants, received two-thirds of CBC and over one-half of CTV coverage. In these reports, either government was blamed for inadequate regulations or industry was blamed as the principal pollutant.

Bruce N. Ames, a professor of biochemistry and molecular biology at the University of California, is concerned that there is: "a public misconception that pollution is a significant contributor to cancer and that cancer rates are soaring." He points out that: "Cancer is fundamentally a degenerative disease of old age, although external factors can increase cancer rates (cigarette smoking) or decrease them (fruits and vegetables)." [Ames, Bruce N. (1993), "The Topic of Cancer--Sierra Magazine vs. Bruce Ames," The American Spectator, June, p. 38.]

The fact that Canadians believe that the causes of cancer are beyond the control of the individual supports Dr. Ames' belief. Instead of focusing on the lifestyle decisions which can significantly reduce one's risk of getting cancer, the television networks focused on the environmental causes of cancer which pose a relatively small risk but are not within the control of the individual. This attention to the causes of cancer may have been a factor in the finding that Canadians think that cancer is "a powerful disease with a mysterious course of its own, controlled by fate and not by its victim."

METHODOLOGY

Results are based on a census sample of 61 National, 44 Journal, 6 Prime Time News, and 1 Venture stories as well as 101 CTV National News stories from January 1, 1988 to December 31, 1992. All stories appearing during that time were coded, representing a total population rather than a random sample of stories.

Three researchers were employed in coding the news stories. The researchers were selected on the basis of their differing political views. To assess the clarity of the research instrument and measure consistency, tests of inter-coder reliability were conducted throughout the procedure. A high level of intercoder reliability (0.82) was obtained.

Any disagreements in assessments by researchers were discussed, and the rating was changed until consensus was reached on all stories. Further information or details on the coding design and methods may be obtained by contacting the National Media Archive.

Networks Focus on Chemicals as a Cause of Cancer

TELEVISION ATTENTION TO THE ENVIRONMENTAL causes of cancer is shown in figure B. Man made chemicals constituted almost 25 percent of CBC and 30 percent of CTV attention to the environmental causes of cancer. These reports primarily focused on dioxins, furans and polychlorinated biphenyls (PCBs). However, the Doll and Peto study found that industrial products caused less than 1 percent of cancer deaths. [Doll, R., and Peto, R. (1981), Ibid.]

For example, when well-water was banned in the town of Newcastle, New Brunswick due to excessive levels of polyaromatic hydrocarbons (PAH), CBC and CTV both followed the story. However, the "facts" were presented in a slightly different manner.

On the April 19, 1989 CBC's The National reporter Bob Merzerol stated that the main town well had been shut down "when it tested positive for cancer-causing polyaromatic hydrocarbons." While the well contained three and a half times the acceptable level, this report gives the false impression that any trace of the chemical will cause cancer.

In contrast, on the April 23, 1989 CTV News Jonathan Gravener reported that the well had "excessive levels." Gravener also reported that these same chemicals are part of everyday life: "It's a chemical that's been linked to cancer . . . PAH is a residue of combustion. Levels can be found in barbecued meats and cigarettes." By including this additional information, the CTV report gave the viewer perspective on the relative danger of PAH.

CBC blames government and industry

This incident prompted the New Brunswick government to conduct a study in order to determine whether or not the people of that region had a higher risk of getting cancer than people elsewhere in the province. The study, based on 500 families and conducted over two years, found that the people of Newcastle were in no greater danger than people elsewhere in the country. The report found that cancer rates were higher in New Brunswick than elsewhere in Canada due to diets too high in salt, fat and alcohol and due to too much smoking.

Click here to view Figure: TV Attention to Industrial Products as a Cause of Cancer Compared to Real World Estimate of Cancer Deaths

CBC reported the findings of this study on the July 23, 1990 The National. However, instead of using the findings of the study to highlight the dangers of excessive fat, salt, alcohol and tobacco consumption, CBC simply questioned the government study.

Reporter Susan Bonner began the story with the statement: "Marg Gorbert is one of hundreds of people in Newcastle who live in fear of cancer. Within six years she lost her mother, her sister and her husband to the disease. She thinks pollution, probably in the water, causes it. She calls the latest study a `government cover-up.'"

This statement was made before the viewer was even told the results of the study. In the entire report, 11 statements were made which questioned the findings, while only 4 statements reported the results of the study. Bonner concluded the story: "Marg Gorbert says she has lost too much. It will take more than one new government study to change her mind."

While the study found that it was the lifestyle decision of the inhabitants of Newcastle which had resulted in the higher cancer rates, CBC's report placed the blame on the government and, indirectly, local industry. Bonner stated: "Newcastle is an industry town in New Brunswick's Miramichi area. There's a pulp mill here and a chemical plant. Two years ago cancer-causing chemicals were discovered in the town's water."

In fact, few studies have proven a link between industrial waste products and increased cancer rates. The B.C. Cancer Agency analyzed cancer rates for 15 regions throughout British Columbia which have had pulp mills since 1970. While the initial analysis showed higher rates of lung cancer, when the data was adjusted for a greater incidence of cigarette smoking the findings "ceased to be significantly high." [Wigod, Rebecca (1992), "Coming to grips with the cold hard hand of cancer," The Vancouver Sun, June 8, p. A1, A3.]

Cancer Process Rarely Explained

IT IS COMMONLY THOUGHT THAT THE TERM CANCER refers to a single disease. However, cancer is actually a term for a large group of diseases which follow the process of carcinogenesis. The initial stage involves either a genetic mutation and/or the killing of cells in an area. Following this the mutated cells multiply abnormally and invade normal cell tissue.

In this study, all references to the steps involved in cancer, or even references to the fact that cancer is a multi-stage process, were noted. On CBC, reference to cancer as a process occurred only three times over the five years of the study. CTV provided slightly more information than CBC, and mentioned the route to cancer five times over the course of the study.

Television Portrays Skin Cancer Epidemic

OZONE DEPLETION WAS THE MOST OFTEN CITED cause of cancer by the national television networks. Twenty-five percent of CBC and over 40 percent of CTV attention to the environmental causes of cancer focused on ozone depletion. A similar trend is shown by the television attention to the type of cancer (figure C). Forty-seven percent of CBC and 44 percent of CTV attention to the various cancer sites focused on skin cancer.

Click here to view Figure C: TV's References to Type of Cancer

However, the risks posed by excessive exposure to sunlight and ozone depletion are relatively small. While sun tanning is the cause of approximately one-quarter of cancer incidence, the vast majority of these cases are curable. Only one form of skin cancer, melanoma, is considered deadly, and as melanoma is relatively rare, skin cancer accounts for only 1 percent of cancer deaths.

However, this fact was not mentioned by either CBC or CTV. For example, on the March 30, 1992 CTV News reporter Michael O'Byrne stated: "Melanoma is the deadliest form of skin cancer, and Dr. Abarca predicts he'll treat a massive outbreak in the next few years." Following this statement ozone researcher Dr. Bedric Magas predicted a 20 to 40 percent increase in the incidence over the next ten years.

Similarly alarmist reports were given on CBC. On the July 21, 1992 Journal by Dr. Robin Marks: "There's no doubt in my mind that in order to get a sun tan, is enough sunlight to lead to the epidemic of skin cancer that we're seeing in Australia, you're seeing in Canada, they're seeing in the United States, Britain, Europe, South America, throughout the western world. Melanoma is rising at a rate that no other cancer is rising. It's becoming the cancer of the late 20th century."

On the April 4, 1991 The National, CBC reporter Eve Savory reported that there had been a "1,250 percent increase in the most lethal skin cancer, melanoma" over the past 55 years. Following this statement, environmentalist Robert Hornung stated: "Every one percent decline in the ozone layer leads to a three to four percent increase in the rate of skin cancer. And in Canada we're already near an epidemic level of skin cancers."

Link between ozone and skin cancer overstated

However, according to Mary Roach, an editor of Health magazine: ". . . there's more to the story than ozone. This is especially true of melanoma. Melanoma risk is a complicated conspiracy of genes and moles and childhood sunburns. The hole in the sky plays a role, but not the lead." [Roach, Mary (1992), "Here's the hole story about the ozone and your chance of getting skin cancer: Sun Struck," Health, May/June, p. 42.]

CFCs consistently blamed for ozone depletion

In addition to overstating the link between ozone depletion and melanoma, the reports consistently blamed CFCs for the reduction in the ozone layer without acknowledging that scientists are still debating the issue. For example, on the April 5, 1992 Journal Barbara Frum stated: "The depletion of the ozone layer is something scientists have been wrestling with for years. They know chemicals like CFCs . . . eat away at the layer once they're released into the atmosphere."

However, neither CBC nor CTV reported that ozone readings have always experienced great fluctuations. James Hogan, a writer for Omni magazine points out that: "The ominous term `ozone hole' was coined by a media machine well rehearsed in environmental politics, and anything the scientific community had to say has been drowned out. Missing from the press and TV accounts, for instance, is that an unexpectedly low value in the Antarctic winter-spring ozone level was reported by the British scientist Gordon Dobson in 1956--when CFC's were barely in use." [Hogan, James (1993), "Ozone politics: they call this science?" Omni, vol. 15, p. 34.]

Click here to view Figure: TV Attention to SKin Cancer Compared to Real World Estimate of Deaths from Skin Cancer

Television fails to blame tanning

Some scientists go so far as to say that there is no relationship between the depletion of the ozone layer and the increased incidence of skin cancer. According to Martin Weinstock of the Rhode Island Moles and Melanoma Unit: "What's been happening with melanoma rates is in no way related to ozone. . . . It's the emphasis on having a tan." John Hastings of the American Cancer Society points out that: "Skin cancer rates have been climbing ever since French designer Coco Chanel came back from a cruise sporting a tan in the 1920s and sent everyone scrambling for a place in the sun." [Roach, Mary (1992), Ibid, p.42.]

While sunlight is the primary cause of skin cancer, the television reports downplayed this cause. On CBC, statements linking ozone depletion with cancer were twice as frequent as statements which simply focused on sunlight. On CTV, ozone depletion received four times more coverage than sunlight.

Good news about melanoma not reported

While both networks focused on the increased incidence of melanoma, neither CBC nor CTV reported the good news that the odds of being alive five years after being diagnosed with melanoma had increased significantly. In the early 1970s, the five year survival rate for melanoma was 65 percent for men and 85 percent for women. By the early 1980s this probability had increased to 82 percent and 88 percent for men and women respectively. And as figure D on page 7 shows, one's risk of either developing or dying from melanoma is relatively small.

Click here to view Figure D: Lifetime Probability of Developing and Dying from Cancer in Canada

CBC Portrays Pesticides as Definite Cause of Cancer

THE CANCER RISKS ASSOCIATED WITH PESTICIDES were treated very differently by the two national networks. On CBC, pesticides constituted over 20 percent of attention to the environmental causes of cancer. In contrast, on CTV, pesticides accounted for only 7 percent of the coverage. Yet Doll and Peto estimate that pesticides in pollution causes only 2 percent of all cancer deaths. [Doll, R., and Peto, R. (1981), Ibid.]

Click here to view Figure: Television Attention to Pollution as a Cause of Cancer Compared to Real World Estimate of CAncer Deaths

Another significant difference between the networks is the manner in which these studies were reported. Of the coverage devoted to pesticides, more than 60 percent of CBC statements presented these substances as a definite cause of cancer. In contrast, on CTV less than 10 percent of the statements linked pesticides with cancer in a definitive manner. Instead, the vast majority of CTV's coverage stated that pesticides were a suspected cause of cancer.

The significance of these findings is even more apparent when one considers how substances are determined to be carcinogenic. Most product test-ing is conducted on laboratory rats. Using a process called maximum tolerated dose (MTD), researchers determine the level of a chemical that will kill the animal and then give it a little less than that every day.

According to Dr. Ames: "Animal cancer tests are being misinterpreted to mean that low doses of synthetic chemicals and industrial pollutants are relevant to human cancers...testing at the MTD frequently can cause chronic cell killing and consequent cell replacement, a risk factor for cancer that can be limited to high doses." [Ames, B.N. (1993), "Current Cancer Risk Assessment May Harm Health--Linear Extrapolation From High Doses in Animal Experiments to Low Doses in Human is Scientifically Invalid," Draft Statement for International Center for a Scientific Ecology.]

CBC debates risk of carcinogens

One of the reasons that pesticides received more attention on CBC than on CTV is because an entire edition of The Journal was dedicated to the issue. On May 2, 1989 Barbara Frum asked a panel of experts whether consumers should be concerned about the fresh produce being sold in Canada. While the other two panellists agreed that Canadians had no cause to be worried, environmentalist and Executive Director of "Friends of the Earth" Julia Langer replied: "Well, frankly, Barbara, I don't think we know enough about the kinds of chemicals that are on the food, what the effects are on ourselves and on the environment to really be able to say with confidence that the food is safe...There are carcinogenic substances in the food--and no safe level of those is conceivable--so I think it's a bit presumptuous to be taking the approach that it's all safe."

However, according to Dr. Ames: "Approximately half of all chemicals--whether natural or synthetic--that have been tested in standard animal cancer tests have turned out to be carcinogenic." Further, Ronald Hart of the National Center for Toxicological Research pointed out that the cancerous tumours found in rodents are likely unrelated to the carcinogen which is being tested. "We feed rodents `all-you-can-eat' buffets every day, yet we know that calorie intake is the single greatest contributing cause of cancer. In fact, we found that you can modify the cancer-causing impact of one of the most potent carcinogens from 90 percent down to less than 3 percent, just be cutting calorie intake 20 percent." [Brookes, Warren T. (1990), "The wasteful pursuit of zero risk," Forbes, April 30, pp. 161-170.]

In the same Journal Ms. Langer called for complete withdrawal of pesticide use. She stated: "These are chemicals which are put deliberately into the environment, which have health effects, environmental effects, effects on wildlife, and-if we can grow fruits and vegetables, and we can, without pesticides-then we should, for public health and for environmental health."

In contrast, Dr. Ames believes: "all this business of organic food is nonsense basically. We should be eating more fruits and vegetables, so the main way to do that is to make them cheaper. Anything that may make fruits and vegetables more expensive may increase cancer."

Diet and Tobacco Receive Little Attention on National Television Networks

DOLL AND PETO ESTIMATED, USING AMERICAN data, that diet and tobacco accounted for 35 and 30 percent of all cancer deaths. In a similar analysis of cancer deaths rates for Albertans between 1984 and 1988 it was discovered that diet and tobacco were: "the most important causes of cancer death in Canada." [Birdsell, J.M. et al (1990), Ibid, p. 41.]

Smoking caused almost 30 percent of cancer deaths. [Birdsell, J.M. et al (1990), Ibid, p.67] However, the national television networks paid little attention to the link between lung cancer and smoking. Over the five years of the study, tobacco was cited as the cause of cancer in only 2.4 percent of CBC and 10.3 percent of CTV reports on cancer causes.

Click here to view Figure: Television Attention to Tobacco as a Cause of Cancer Compared ro Real World Estimate of Cancer Deaths

For example, when an international study predicted that over one-million women would die from lung cancer each year, CBC did not provide a report and CTV's anchor simply announced the findings. On the April 1, 1992 CTV News Lloyd Robertson stated: "A major worldwide study predicts that over one million women will die each year from lung cancer and other tobacco-related diseases by the year 2020. The World Health Organization says young women are now taking up smoking faster than men, and it appears that women smokers face more health hazards, especially if they smoke while pregnant."

Diet ignored as cause of cancer

Dietary factors also received little television attention. Oxford researchers Doll and Peto found that the best estimate for diet as a factor in cancer deaths was 35 percent. [Doll, R., and Peto, R. (1981), Ibid.] The study undertaken using Canadian data found diet to be responsible for 33 percent of cancer deaths. [Birdsell, J.M. et al (1990), Ibid, p.67] In fact, there is almost unanimous agreement within the scientific community that high fat and high calorie intake and excessive alcohol consumption are the primary factors in dietary related cancers.

The Canadian Cancer Society reiterates these findings. According to the consumer guide Healthy Eating: Reducing Your Risk of Cancer, the major dietary risks are too much fat, too many calories leading to obesity, too much alcohol and not enough fruits, vegetables and whole grains. [Healthy Eating: Reducing Your Risk of Cancer, Canadian Cancer Society, 1992, p. 3.]

Yet, discussion on the national television networks regarding the links between a balanced diet and a significantly reduced risk of cancer comprised only 5.6 percent of CBC and 10.3 percent of CTV total attention to the causes of cancer.

Click here to view Figure: Television Attention to Diet as a Cause of Cancer Compared to Real World Estimate of Cancer Deaths

The reasons for this lack of coverage may partially be explained by Dr. Robert Scheuplein of the Food and Drug Administration. He states: "When risks are perceived to be dread, fatal, unfamiliar, uncontrollable by the individual, unfair, involuntary, and potentially catastrophic, they are typically of great public concern (or `high outrage'). [When risks are perceived as voluntary, controllable by the individual, familiar, equitable, easily reducible, decreasing and non-catastrophic, they tend to be minimized by the public (or `low outrage')." Scheuplein, Robert (1991) "Do Pesticides Cause Cancer?" Consumers' Research, December, pp. 30-33.]

Dr. Scheuplein further concludes that people consistently underestimate the hazards of low-outrage risks and overestimate the hazards of high outrage risks. He then suggests that the link between healthy eating habits and a reduced risk of getting cancer is ignored by the media because of their subjective evaluation of a "low outrage" risk.

"The widely acknowledged risks from an improper diet have scarcely caused a ripple in the media or in the public's consciousness. It is perhaps a perfect illustration of a `low-outrage' subjective risk. Eating is completely under the control of the individual--among the most familiar of all activities. It is voluntary at least in the sense of choosing the foods you want to eat, it is believed by most to be absolutely safe." [Scheuplein, Robert (1991), Ibid, pp. 30-33.]

However, given the media's fundamental role in providing accurate and balanced information which will allow the public to make informed decisions, it is surprising to find that the television reports virtually ignored these vital although perhaps mundane studies.

Networks look at dietary fat and breast cancer

While only a small fraction of CBC's and CTV's attention to the causes of cancer focused on diet, the majority of these statements debated whether or not fat was linked to breast cancer.

For example, on the October 20, 1992 The National, anchor Peter Mansbridge gave this report: "No one knows what causes breast cancer. Some researchers have suggested that it may be linked to a diet that's high in fat. But a new study says dietary fat doesn't cause breast cancer and fibre doesn't prevent it. More than 89,000 American women were studies over eight years. The results are published in this week's Journal of the American Medical Association. But they only apply to breast cancer. Other studies have found a strong link between dietary fat and cancer of the colon."

Is There a Cancer Epidemic?

ON THE FEBRUARY 28, 1989 Dr. John McCarthy, vice-president of the National Agricultural Chemicals Association, was interviewed on The Journal in a debate regarding pesticides and carcinogens. He stated: "The good news is we don't have a cancer epidemic in this country. This means that we can tolerate small amounts of chemicals that cause cancer, large amounts in laboratory animals, and now--that's the good news--and the statistics, in terms of our health, bear this out."

To this statement, Barbara Frum responded: "I think a lot of you, who know the cancer death rate, are wrinkling their nose--when you say we don't have a cancer epidemic in this world."

While the incidence of cancer has been increasing, it is primarily due to the emphasis on early detection. The more telling statistic, cancer death rates, have either improved or remained constant, with the exception of lung cancer, since the 1970s (see figure E).

Click here to view Figure E: Percent Change in Mortality Rates, Including and Excluding Lung Cancer

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Last Modified: Wednesday, October 20, 1999.