MONDAY, Dec. 14, 2015 (HealthDay News) -- Better screening and lifestyle changes have helped to reduce the prevalence of common cancers in many high-income countries, but low- and middle-income countries are seeing those rates rise as they adopt unhealthy Western habits.
In 2012, an estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred worldwide, and the number of cancer cases and deaths are expected to grow rapidly as populations increase, get older and adopt lifestyles that raise the risk for cancer, researchers report.
"It's not surprising that the highest rates of cancer are still in high-income countries," said study author Lindsey Torre, an epidemiologist at the American Cancer Society.
The highest cancer rates are for colon, lung and breast cancer, which are related to lifestyle factors such as smoking and obesity, she said.
"But what's interesting is that in low- and middle-income countries, we are starting to see rising rates of the same cancers that have been common in high-income countries because of the uptake of Western lifestyles, like smoking and excess body weight," Torre said.
As countries get wealthier, people tend to smoke more, eat more junk food and be less physically active, thus increasing the likelihood of certain cancers associated with these changes, she said.
For the most part, these countries are in South America, Africa and Asia, Torre said.
"For low- and middle-income countries, it doesn't look good," Torre said. As the incidence of these cancers increase, these nations may not have the resources to deal with this growing burden. Many of these countries do not have screening programs and they may not be able to catch and treat these cancers as well as richer nations can, she said.
"At the same time, these countries still have a high burden of cancer related to infections, which are less common in high-income countries," Torre said. These include stomach cancer, liver cancer and cervical cancer.
"So for these countries, it's a double burden," she said.
The report was published Dec. 14 in the journal Cancer Epidemiology, Biomarkers & Prevention.
Using data from an international cancer database, Torre and her colleagues from the American Cancer Society collected data on cancer cases and deaths from 2003 to 2007.
Specifically, they looked at eight major cancers -- breast, prostate, colon, lung, esophageal, stomach, liver and cervical cancers. Together, these account for 60 percent of cancer cases and deaths in the world, the researchers said.
Dr. David Katz, director of the Yale University Prevention Research Center and president of the American College of Lifestyle Medicine, said, "This paper is an important, timely reminder of our considerable capacity to influence the frequency of cancer, as well as the course of the disease."
Cancer treatments are improving in high-income countries, and this explains better cancer outcomes, he said.
"But declines in cancer rates are proof that when we address risk factors, from smoking to infectious agents to diet, cancer is often preventable," Katz said.
"In this context, it is both tragic and unconscionable that risk factors for cancer and other chronic diseases are being actively exported by wealthy countries to developing countries," he said.
For example, as barriers to the sale of cigarettes in the United States have mounted, tobacco exports have increased. The United States is also exporting fast food, junk food, soda, labor-displacing technologies and lifestyle practices that foster obesity and diabetes, he said.
"We are exporting causes, and thus cases, of cancer," Katz said. "Profit is being prioritized over human lives. Knowing this, and continuing in that vein, is all to our shame."
Visit the World Health Organization for more on cancer.