THURSDAY, March 31, 2005 (HealthDay News) -- Despite gains, a new report finds that half of all cancers could still be prevented through early detection and lifestyle changes.
Tobacco use, physical inactivity, obesity and poor nutrition remain the major preventable causes of cancer and other diseases in the United States, according to the American Cancer Society (ACS) report released Thursday.
"We have sufficient knowledge of cancer causes and prevention that could prevent cancer burden in the U.S. by at least half," said Vilma Cokkinides, one of the lead authors of the report and program director of risk factor surveillance for the ACS in Atlanta. "A healthy lifestyle coupled with early detection and treatment is the best personal weapon each of us has to fight this disease."
"It just reinforces the two messages: quit smoking or don't start, and get screened [for cancer]," added Dr. Ronald Blum, director of Beth Israel Cancer Center in New York City. "The message bears repeating."
The ACS estimates that about one-third (570,280) of cancer deaths in this country in 2005 can be traced back to poor nutrition, lack of exercise, overweight and obesity and other lifestyle factors. And although tobacco use is down, the society predicts that this year smoking will still be the underlying cause of more than 168,140 cancer deaths.
Overweight and obesity could cause as many as one in seven cancer deaths in men and one in five such deaths in women, the report adds. Having a high body mass index increased death rates for 11 types of cancer in men and 12 in women, according to a 2003 report by the ACS.
Other cancers, including colon and cervical, can be prevented by better screening. Despite this knowledge, more than half the Americans over age 50 do not get tested for colorectal cancer, the ACS experts said.
The report found similar trends in both children/adolescents and in adults.
Smoking rates among high school students were 21.9 percent in 2003, down from 36.4 percent in 1997. This reduction can be at least partially attributed to increased taxes on cigarettes, public smoking restrictions, advertising and tobacco control programs.
"Comprehensive tobacco control programs, such as those in California and Massachusetts, have had a high impact in shifting smoking levels," Cokkinides said.
These efforts need to be extended to the overweight/obesity epidemic, Cokkinides added.
The proportion of overweight or obese children and adolescents has soared in the United States over the last two decades, the report notes. Among children aged six to 11, rates of overweight and obesity rose from 6.5 percent in 1980 to 15.8 percent in 2002; among youth 12 to 19 years old, it almost tripled, from 5 percent to 16.1 percent.
Much of the problem can be attributed to sedentary behavior, with 38 percent of high-school students watching at least three hours of television a day and only 38.4 percent of students enrolled in daily physical education classes.
Skin cancer is also largely preventable, yet only 15 percent of high-school students say they use sunscreen when in the sun for more than an hour, the report stated.
Smoking rates in adults has also declined, but not enough, according to the report, which finds 25.2 percent of men and 20.7 percent of women still addicted to cigarettes. Overall, 45.8 million Americans currently smoke.
American adults are getting heavier, too. In 2002, about two-thirds of adults were overweight and almost one-third were obese. Again, much of this can be attributed to too little physical activity and poor eating habits. Only 23.5 percent report eating the recommended five or more servings of fruits and vegetables each day while just 45.4 percent get the recommended amount of exercise.
Physical activity is known to reduce the risk of breast and colon cancer and may also help protect against endometrial and prostate cancer. People who have a diet high in fruits and vegetables also seem to have a reduced incidence of cancers of the mouth and pharynx, esophagus, lung, stomach, kidney, colon and rectum, according to the ACS.
Screening is the other major way to decrease the risk of certain cancers. While screening for different cancers has increased, it is still not at optimal rates. Colorectal cancer screening is the most notable example. Only 39 percent of U.S. adults over 50 get this recommended screen.
"Both cervical and colon cancer can be prevented through screening," Blum said. "The message just doesn't get any clearer and yet the screening rates for colon cancer are low."
Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Clinic Foundation, in Baton Rouge, agreed. "Screening tests for breast, colon, prostate, skin and cervical are all very easily affordable and attainable by most people," he said. "As a cancer specialist, my goal is to try to prevent people from ever seeing me."
Brooks added that it costs about $6,000 to maintain a car for five years. Following ACS guidelines for doctor's visits and life-saving screening would cost about $2,500 over that amount of time, before insurance, he said.
The next frontier in cancer prevention is to take some of the successes in tobacco control and see if they can be replicated to combat overweight and obesity.
"We have made a lot of progress with smoking reduction," Cokkinides said. "We need to do the same for nutrition and physical activity so we can impact obesity. Obesity needs the most work."
For more on different types of cancer, visit the American Cancer Society.