The World Health Organization predicts that the number of worldwide cancer cases could soar by more than 50 percent in the next two decades if lifestyles do not change. The WHO points to smoking and obesity as the two major preventable causes of tumors.
Ten million new cancer cases were diagnosed around the world in 2000, and six million people died of the disease. A new World Health Organization report says the caseload could grow to at least 15 million by 2020, with nine million deaths.
And that's a conservative estimate. WHO cancer research director Paul Kleihues says last year's International Cancer Congress is Oslo heard more dire predictions of a doubling of cancer incidence by 2020.
"It is not unrealistic. However, we prefer a conservative estimate because we do not want to scare people," he said. "Even with a conservative number, it's scary enough."
Dr. Kleihues says the WHO report shows that cancer is no longer a disease only of affluent nations. It has become a major health problem in developing nations, too.
The report says the main reasons are steadily aging populations, high smoking rates, and the spread of an unhealthy Western lifestyle rich in fatty foods and poor in exercise.
Although the industrial world is still far ahead in the number of cancer cases, Dr. Kleihues predicts that developing countries will catch up if current trends in diet, exercise, and tobacco use continue. He says this is especially true of newly industrializing nations.
"India, China and many Asian countries will adopt the Western lifestyle, and we see in these countries an increase in tumors that they rarely knew," he said. "To what extent and how fast is difficult to predict. That's the reason we were conservative with the numbers."
The developing world's high burden of infectious diseases adds to their problem because many cause malignancies. Some hepatitis viruses, for example, cause liver cancer, while a papillomavirus causes cervical, anal, and genital cancers.
The World Health Organization says cancer screening and advances in drugs and vaccines hold hope for avoiding tumors, but notes that healthy behaviors are key.
The cancer prevention chief of the U.S. National Cancer Institute, Dr. Peter Greenwald, agrees. "Tobacco control obviously is number one," he said. "A second is other aspects of lifestyle, particularly avoiding obesity, which is a large epidemic in the United States and many other parts of the world, meaning eat less and exercise more."
The World Health Organization says it is working to curb the global rise in cancer by promoting the Framework Convention on Tobacco Control, a groundbreaking public health treaty that member nations will vote on at the World Health Assembly next month. The agency is also preparing a global strategy on diet and physical activity.
Dr. Greenwald hopes the WHO continues its firm stand on these issues after Director General Gro Harlem Brundtland's term of office ends in July.
"The WHO has had excellent leadership, so I hope that with the new leadership, they will maintain and build upon what they've been doing," he said.