In 1996 Donna Shalala, U.S. Secretary of Health and Human Services, declared that the war on cancer was finally showing results. "This looks like a turning point in the 25-year war on cancer, and it should be cause for celebration by every American," she said.[1] Shalala made her dramatic pronouncement to underscore the fact that the death rate for all cancers combined had declined 2.6% during the period 1991-1995. It was the first sustained decline since the government started keeping cancer statistics in the 1930s.
Cancer deaths declined for cancers of the lung and prostate in men, breast and uterus in women, and colon/rectum in both sexes. Since these are the most common cancers, they drove down the overall death rate.
We suspect that these reported trends are questionable because reputable studies indicate that many cancers remain undiagnosed unless an autopsy is performed, and autopsy rates have declined in recent years (see REHW #631).
However, for purposes of discussion, let's assume that the government is right, that age-adjusted deaths from all cancers combined really did decline 2.6% between 1991 and 1995.
Despite this bit of good news, the details of cancer in this country are still awful. Cancer struck 1,228,000 Americans for the first time in 1998, and 564,800 Americans died of cancer in 1998.[2] A man's chances of getting cancer during his lifetime are now 48% (about 1 out of 2) and a woman's chances are now 38% (about 4 out of 10). Clearly, we have a very long way to go before we can claim that the "war on cancer" has been won.
Furthermore, the good news about cancer hides some terrible injustices. For example, the largest declines in cancer death rates between 1991 and 1995 occurred among African-Americans. The death rate for all cancers combined declined 5.6% among blacks between 1991 and 1995. The decline was especially great among black men, whose cancer death rate decreased 8.1%, compared to black women, who experienced a 2.5% decline during the same period.
Despite this good news, the overall age-adjusted cancer death rate is still 40% higher among black men compared to white men, and 20% higher among black women compared to white women.[1]
Why do blacks die of cancer so much more than whites? The Director of the National Cancer Institute, Richard Klausner, phrases it delicately: "less access to care and less aggressive treatment" play a role, he says.[1] Less aggressive treatment? There is an extensive body of literature showing that many physicians give second-class medical care to black patients.[3] Perhaps this occurs because blacks tend to be poorer than whites, but perhaps it also results from a widely-shared (and perhaps subconscious) racist view that blacks deserve less than whites.
The "cancer establishment" has a ready explanation for the declining death rates from all cancers combined. They say roughly half the overall 2.6% improvement in cancer death statistics, 1991-1995, can be accounted for by improvements in "life style" -- less smoking, better diet, more exercise. They say the other half results from better diagnosis and treatment -- more people are being kept alive by chemotherapy, radiation, and surgery.
But Richard Clapp at the Boston University School of Public Health points out that heart disease is caused by these same factors -- smoking, bad diet and insufficient exercise.[4] Because of improvements in these factors, deaths from heart disease have declined 49% during the past 25 years. If heart disease and cancer are caused by the same factors, why has the cancer death rate remained so high? It cannot be simply that cancer is a disease of old age. Heart disease, too, is a disease of old age. Is something else besides "life style" factors causing cancer? It is a fair question.
We note that in a 1990 cancer prevention booklet titled EVERYTHING DOESN'T CAUSE CANCER, the National Cancer Institute (NCI) says, "Many cancers could be prevented by reducing our exposure to carcinogens."[5] The NCI identifies 30 chemicals or industrial processes that are known to cause cancer in humans. Furthermore, NCI says, "Of the several hundred other chemicals that cause cancer in animals, however, it is not known how many are also human carcinogens. Nevertheless, materials that cause cancer in one type of animal usually are found to cause cancer in others.... For these and other reasons, we should expect animal carcinogens to be capable of causing cancer in humans."
The NCI goes on to explain why weak cancer-causing chemicals cannot be reliably identified among the 70,000 chemicals now in industrial use. In a typical test of a chemical for carcinogenicity, "groups of about 50 mice or rats of each sex are exposed to the test substance at different dosages for about two years." At the end of the experiment, the animals are killed and examined for cancer.
NCI goes on: "In the human population, large numbers of people are exposed to low doses of chemicals, but the total impact may not be small at all. For example," NCI says, "a carcinogen might cause one tumor in every 10,000 people exposed to it, which may not seem great. But exposure of 230 million Americans would result in 23,000 cancers -- a public health disaster."
NCI goes on: "We obviously could not identify a carcinogen that causes one cancer in every 10,000 exposed mice by running the test on only 50 mice. To detect such a low cancer rate, we would need tens of thousands of mice. This would cost many millions of dollars per test. Testing more than a few chemicals in such a fashion would be too expensive and time-consuming," NCI says.
NCI also points out that it is difficult to identify which carcinogens cause which cancers because "A chemical that causes cancer of the liver in mice, for example, might cause cancer of the breast in rats and cancer of the bladder in humans."
Is there a safe level of exposure to a cancer-causing chemical? NCI says no: "There is no adequate evidence that there is a safe level of exposure for any carcinogen." And "Low exposure that might be safe for one person might cause cancer in another.... Unfortunately, scientists have not yet developed any way to measure a person's individual risk. Exposure to a low level of a carcinogen thus has to be considered a risk for everyone," NCI says.
Here is the big picture of cancer: Table 1 shows that during the last 45 years, the incidence of all cancers combined has risen 1.0% each year and the death rate for all cancers has increased at the rate of 0.2% each year. If we exclude lung cancer, the increase in the incidence of all other cancers is still 0.8% each year for the past 45 years, but the death rate has declined at the rate of 0.4% each year. A rising incidence and a dropping death rate, taken together, mean more people are learning to live with cancer.
--Peter Montague (National Writers Union, UAW Local 1981/AFL-CIO)
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[1] Mary Jo Hoeksema and Catherine Law, "Cancer Mortality Rates Fall: A Turning Point for the Nation," JOURNAL OF THE NATIONAL CANCER INSTITUTE Vol. 88, No. 23 (December 4, 1996), pgs. 1706-1707.
[2] Lynn A.G. Ries and others, SEER CANCER STATISTICS REVIEW, 1973-1995 (Bethesda, Maryland: National Cancer Institute, 1998).
[3] For example, see the first 19 studies cited in Kevin A. Schulman and others, "The Effect of Race and Sex on Physicians' Recommendations for Cardiac Catheterization," NEW ENGLAND JOURNAL OF MEDICINE Vol. 340, No. 8 (February 25, 1999), pgs. 618-626.
[4] Richard W. Clapp, "The Decline in U.S. Cancer Mortality from 1991 to 1995: What's Behind the Numbers?" INTERNATIONAL JOURNAL OF HEALTH SERVICES Vol. 28, No. 4 (1998), pgs. 747-755.
[5] National Cancer Institute, EVERYTHING DOESN'T CAUSE CANCER [NIH Publication No. 90-2039] (Bethesda, Maryland: National Cancer Institute, March, 1990).
Search terms: cancer; carcinogens; heart disease; morbidity statistics; mortality statistics; national cancer institute;
