FRIDAY, Sept. 24 (HealthDay News) -- Cancer is one of the most
feared diseases on the planet, and the second leading cause of
death in the United States.
But medical science is slowly conquering cancer, according to an
assessment of cancer trends produced by the U.S. National Cancer
Institute in conjunction with the U.S. Centers for Disease Control
and Prevention, the American Cancer Society and the North American
Association of Central Cancer Registries.
Death rates and diagnosis rates from all cancers combined are
declining significantly, both for men and women overall, and for
most racial and ethnic populations within the United States, the
New diagnoses for all types of cancer combined decreased an
average of almost 1 percent a year from 1999 to 2006, and deaths
attributed to cancer decreased 1.6 percent a year from 2001 to
2006, according to the report, an annual evaluation released each
Doctors predict that the rates will keep falling because
research has begun unlocking the secrets of how different cancers
begin and develop.
"We're beginning to understand that each cancer has an individual pathway to development," said Dr. Alan G. Thorson, president of the American Cancer Society, a clinical professor of surgery and director of colon and rectal surgery at Creighton University in Omaha, Neb. "We know now how to look at cancer, find its source and go for that source, which makes all the difference in the world."
The decrease in cancer incidence and deaths has been driven
mainly by advances in detecting and treating the major types of
cancer in men and women, according to the report.
Incidence and death rates are declining for lung, prostate and
colorectal cancer in men, and for breast and colorectal cancer in
women, the report said. Also, increases in the other major cancer
for women, lung cancer, have tapered off, with rates remaining
stable since 2003.
There's no single explanation for the decrease in these major
cancers, doctors said. Rather, the decreases are chalked up to
effective detection and treatment tools designed for each form of
For example, public tobacco policy has been crucial in reducing
lung cancer rates in men and leveling them out for women, said Dr.
Brenda Edwards, associate director of the Surveillance Research
Program at the U.S. National Cancer Institute.
"The biggest risk factor for lung cancer is smoking," Edwards said. "We've begun to see the impact of efforts to limit tobacco use." She noted that the reduction in smoking rates has accompanied laws designed to prohibit public smoking.
Colorectal cancer has decreased because of increased efforts to
screen for the cancer using colonoscopy and other methods, Thorson
said. Colonoscopy has made colorectal cancer completely
preventable, he explained, because doctors can remove precancerous
polyps from the colon during the procedure.
A number of factors account for the decrease in breast cancer
rates. Mammograms are providing earlier detection of breast
cancers, and earlier detection most often results in more
successful treatment, Thorson said.
On top of that, fewer women are using hormone replacement
medications after menopause, and "the sudden shift away from
hormone replacement therapies in women affected incidence rates,"
Prostate cancer rates have fallen as the result of improved
detection through the use of tests that measure the level of
prostate-specific antigen (PSA) in a man's blood, which can
indicate cancer likelihood, and improved treatment procedures,
Both Edwards and Thorson believe the key to keeping cancer in
decline involves molecular and genetic research that is unlocking
the way cancer cells function.
"We're beginning to understand what's going wrong inside of the cells to make them behave in a bad manner," Thorson said. This type of research will result in targeted therapies that will attack cancer cells while leaving healthy cells alone, he said.
Increased understanding of the human genome also will help in
cancer prevention, Thorson said. Using knowledge of the genetics of
cancer, doctors might soon be able to identify people who are at
high risk for certain types of cancer and provide them with the
tools to prevent its occurrence.
Other breakthroughs along the way also should help. For example,
doctors are using vaccines to prevent the occurrence of cervical
cancer in women and are researching ways other vaccines might stop
other forms of cancer.
But Thorson said the biggest breakthroughs in cancer prevention
could be ones that people undertake in their everyday lives.
If people begin eating right, exercising and avoiding bad habits
such as smoking, then cancer rates will continue to fall, he
"We have the ability to significantly reduce cancer available right now," Thorson said. "Those are things we can do to prevent cancer, which is infinitely better than creating new ways to treat cancer once it's there."
"People forget how much power we do have right now through simple lifestyle changes," he added.
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