Cancer Changing Profile
Around The World
ATLANTA (Reuters Health) - Major changes are taking place in cancer incidence around the world, with increases in breast, prostate, colorectal and lung cancer, largely due to lifestyle factors.
At the same time, cancer of the stomach, cervix and liver is declining due to better treatment and prevention of infection.
"Three major transitions are taking place in global cancer statistics,'' Dr. Michael Thun announced here at the 2nd World Conference for Cancer Organizations. In Thun's opinion, the increase in lung cancer associated with the increased usage of tobacco products worldwide represents the most important transition.
"That is best illustrated by lung cancer becoming the leading fatal cancer worldwide in the early 1980s,'' said Thun, vice president for Epidemiology and Surveillance Research with the American Cancer Society. "Tobacco-related cancers will predominate in cancer occurrences well into the next century.''
The good news is declining incidence rates for three cancers caused in part by infection, including stomach, cervical, and liver cancer. Stomach cancer can be caused by Helicobacter pylori bacteria, cervical cancer can result from infection with the sexually transmitted human papillomavirus, and liver cancer is associated with hepatitis B infection, said Thun. He attributed the declining rates to more widespread treatment and preventive screening.
Developing countries have begun to adopt a "Western'' lifestyle, and are thus experiencing a rise in the breast, prostate and colorectal cancers that are associated with such a lifestyle. However, the increase in tobacco use is of greatest importance, according to Thun.
"The tobacco transition dominates the other two, not just because of cancer but because it impacts health in so many other ways. It is very important for physicians to continue to counsel their patients to quit smoking. For cancer, reducing smoking is the single most important priority worldwide,'' Thun told Reuters Health.
In the year 2000, there will be an estimated 8 million deaths from cancer, he said. Thun noted that roughly 75% to 80% of cancers in the US are avoidable.
"We are not normally predestined to get cancer. It is mostly brought about by environmental factors,'' he commented.