Death rates continue to drop for the top three cancer killers in men — lung, colon and prostate — and for breast and colon cancer in women, according to the latest American Cancer Society statistics, published Wednesday.
But more U.S. women are dying from lung cancer, the annual report shows.
And more people are dying of obesity-related cancers such as some types of liver and esophageal cancer. The report is posted on the Internet at http://www.cancer.org/statistics.
It estimates that 1.368 million Americans will be diagnosed with cancer in 2004, and 563,700 will die of it. This works out to 1,500 Americans a day.
Colon cancer death rates fell to 20.8 per 100,000 people per year in the latest year available, 2000. That compares to 20.9 per 100,000 in 1999 and 22.6 in 1995. Breast cancer deaths fell from 30.6 per 100,000 in 1995 to 26.7 in 2000, the group said.
Cancer has long been the second leading cause of death in the United States after heart disease, accounting for about a quarter of all deaths.
Lifestyle changes play key role
The statistics show it is possible to avoid many cancers, said Dr. Michael Thun, the Society's vice president of epidemiological and surveillance research.
"Cancer is not an inescapable fact of life," Thun told reporters in a telephone briefing.
Stopping smoking is one way to avoid cancer. The report estimates that tobacco use will cause 180,000 cancer deaths in 2004 — 160,000 of them from lung cancer.
In women, the epidemic of deaths from lung cancer trails that of men by about 25 years. This matches the decrease in smoking rates — women started smoking later than men did and took up smoking even as men started to kick the habit.
A third of cancers will be caused by lifestyle factors such as lack of exercise, poor nutrition including a high-fat diet low in fiber, fruits and vegetables and obesity.
For instance, Thun said, about 20 percent of U.S. adults have a fatty liver from obesity, which can lead to chronic hepatitis. This in turn can lead to cancer and helps explain a rise in liver cancer incidence in the United States.
Early detection technology
Obesity can also lead to stomach and bile reflux, which can irritate the lower esophagus and also eventually cause cancer, Thun said.
But advances in screening technology mean more cancers are being caught early, when they are more easily cured. And treatments, including surgical techniques, drug and targeted radiation therapy, mean the five-year relative survival rate for all cancers combined has risen to 63 percent from 51 percent in 1976.
Thun said it is important to look at cancer rates and not just overall numbers. And they must be adjusted for age to have any meaning.
"Solid tumors are diseases of aging. The number of people who get cancer go up but when you look at the trends in the death rates ... you see that there been a decrease in the death rate from all cancers combined in men ...and a smaller decrease in women. There's clear progress in reducing death rates."
One piece of bad news is that disparities in cancer rates and survival continue to worsen, Thun said.
"Since the early 1980s the differences in the death rate in colorectal cancer between black and white men has widened," Thun said.
He said the death rate has decreased markedly among white men, probably because of screening and early treatment, while the death rates in black men have not changed much. The same is true, on a smaller scale, for women, he added.