NEWS

Cancer Surpasses Heart Disease as Leading Cause of Death for All But the Very Elderly

Renee Twombly

In 1971, when President Richard Nixon declared war on cancer, heart disease was the number-one killer of Americans. Now, a new American Cancer Society report reveals that since 1999, cancer has surpassed heart disease as the primary cause of death in people in this country younger than age 85.

The report, published in the January/February issue of CA: A Cancer Journal for Clinicians, shows that, although rates of death due to cancer and heart disease are both falling, those for heart disease are falling faster in people younger than age 85, who make up 98% of the population and whose deaths account for 72% of all deaths annually. In 2002, the latest year for which mortality figures are available, cancer was responsible for 478,082 deaths and heart disease for 446,727 deaths in that age category. (See Stat Bite, p. 330.)

This news, however, is not as gloomy to the field of oncology as it sounds; if age were set aside, heart disease would still outrank cancer as the number-one killer of Americans. In 2002, 696,947 people in the United States died of heart disease, compared with 557,271 deaths from cancer. This is because heart disease is particularly lethal to those aged 85 and older. In this elderly group, heart disease accounted for three times as many deaths (more than 250,000) as did cancer (nearly 80,000 deaths) in 2002.

Still, the complexities of the report were lost in many of the headlines that appeared nationwide, such as USA Today's "Cancer Now the Top Killer of Americans" and "Cancer Passes Heart Disease as Top Killer" from the New York Times. Some worry that the implied message to the public is that the 34-year-old war on cancer is being lost.

The report's authors compiled the most recent data on cancer incidence and survival from the National Cancer Institute and data on mortality from the National Center for Health Statistics. The report is prepared annually, but this was the first year that the report's authors looked at death rates by age. "Someone asked us what would happen to death from cancer if we looked at [rates among people younger than] age 85, so we decided to do that," said Elizabeth Ward, Ph.D., director of surveillance research for the American Cancer Society and one of the authors of the report.



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Elizabeth Ward

 
The researchers found that, although death rates from all cancers combined have been steadily falling over the past decade (1.5% per year since 1993 among men and 0.8% per year since 1992 among women), the rate of death from heart disease has been declining for much longer, since at least the mid- 1970s. So in 1999, cancer deaths surpassed heart disease mortality in those younger than age 85.

Even in the over-85 category, heart disease mortality has declined relative to cancer, noted Lynn Ries, a health statistician at the National Cancer Institute. "We have gone from six heart deaths per each cancer death in 1970 to three heart deaths per cancer death."

Improvements in mortality rates for both diseases appear to have benefited from reduced smoking rates in the United States, the authors say. The report found that, in women, lung cancer mortality has leveled off after increasing for a number of decades, and mortality rates have fallen in breast and colorectal cancers. In men, the mortality rate has also continued to decrease for the three most common cancer types—lung, colorectal, and prostate.

Ward offered a possible explanation for the change in rates of both diseases: "Improvements in treating risk factors for heart disease have been impressive, and while we have made strides in early detection of cancer, it hasn't been as dramatic," she said. In addition, advances in treatment for cardiovascular disease have also improved in the last four decades.

Also new in this year's report was a special section on infections that can cause cancers. Worldwide, about 17% of cancers are caused by microbes, such as hepatitis B and C viruses, which cause liver cancer, or human papillomavirus, which causes cervical cancer. But as a result of prevention efforts in the United States, only 7% of U.S. cancers are caused by infections, said Ward.

Even still, 70% of cancers in the United States are potentially preventable with attention to known risk factors for the disease, such as smoking, poor nutrition, obesity, and lack of physical activity, said Ahmedin Jemal, Ph.D., program director for cancer occurrence at the American Cancer Society and the main author of the CA report. "The good news is that we have a lot of knowledge that we can use to help prevent cancer development—if only it would be applied," he said.

The fact that cancer is now the leading cause of death for most Americans presents a bit of a public relations issue, some say. The report's "message is a complicated one, but the reality is that you are less likely to die before age 85 of either cancer or heart disease," said Edward Benz Jr., M.D., president of the Dana-Farber Cancer Institute in Boston. "Making clear to the public that this is basically positive news will be a challenge for us in the cancer community."



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Edward Benz Jr.

 
On the other hand, changes in cancer mortality versus cardiovascular mortality might well ratchet up federal dollars devoted to cancer research. "I think it will motivate people to look at cancer research now as the thing that can target the main cause of death," Benz said. "But I also think it would be inappropriate to use this news either to lobby for more cancer funding or to claim the war on cancer is not working."

One of the country's leading heart experts isn't happy that the public now believes cancer is the leading killer of Americans. In an op-ed piece published January 24 in the Houston Chronicle, surgeon Denton Cooley, M.D., president of the Texas Heart Institute, said he worried about "confusing" news reports that pegged cancer as the most lethal disease, because "cardiovascular disease accounts for 38% of all deaths and claims more lives than the next five leading causes of death combined." According to the American Heart Association, cardiovascular disease includes heart disease as well as diseases of the blood vessels, including strokes.



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