The report, issued by the International Agency for Research on Cancer, is a joint effort of over 250 scientists from around the world and published as an effort to highlight the emerging threat of cancer and what the average person can do to protect herself.
Cancer-related deaths are on the rise, too, expected to reach 13 million a year within the next two decades. Currently, 14.1 million cases of cancer are diagnosed each year, a number predicted to increase to 19.5 million over the same time period. Globally, lung cancer claims the most lives, accounting for 19 percent of all deaths, followed by liver cancers (9 percent) and stomach cancers (8.8 percent).
The sad reality is that a third of these deaths and diagnoses could be prevented, the report concludes. Thirty percent of cancers can be tied directly to lifestyle and behavioral risks, says the World Health Organization: high body mass index, low fruit and vegetable intake, lack of physical activity, tobacco use, and alcohol use. In low- and middle-income countries, an additional 20 percent can be linked to vaccine-preventable infections from hepatitis B, hepatitis C virus and some types of Human Papilloma Virus (HPV).
"We cannot treat our way out of the cancer problem. More commitment to prevention and early detection is desperately needed in order to complement improved treatments and address the alarming rise in cancer burden globally," said Dr. Christopher Wild, director of IARC and co-editor of the report, in a statement accompanying its release.
In the U.S., the cancer picture is slightly rosier, says Benjamin O. Anderson, MD, director of the Breast Health Global Initiative at Fred Hutchinson Cancer Research Center in Seattle and professor of surgery and global health at the University of Washington. Although cancer is second-leading cause of death here, cancer deaths have dropped about 20 percent since 1991. And the number of cancer diagnoses here has remained relatively steady over the past decade. "Wwe've been doing early detection for quite some time," he says, "and we've put a greater focus on general health awareness." But he adds that the growing obesity epidemic, which is spreading to low- and middle-income countries, where Dr. Anderson says cancer is an "underappreciated problem," could work against those advances. Americans seem fairly well educated about cancer risks related to smoking, he says, but "we have less of an awareness about obesity, which causes significant health issues."
Obesity is thought to play a role in the development of numerous cancers, among them cancers of the breast, kidney, thyroid, rectum and pancreas. And Dr. Anderson says, emerging research is investigating the potential that insulin changes brought on by diabetes, itself driven by obesity, could cause cancer too.
The United Nations revealed in a 2011 report that non-communicable diseases—cancer as well as other lifestyle diseases such as heart disease and diabetes—now kill more people worldwide every year than infections such as HIV/AIDS, malaria or cholera, the first time in history that that's ever been the case. That report noted that non-communicable diseases emerged "relatively unnoticed" and are now a global epidemic.
At the time, the UN urged many of the same preventative measures that the International Agency for Research on Cancer is suggesting now to stem what one of the report's authors called "a tidal wave of cancer":
• raising taxes and bans on advertising and smoking in public places;
• raising taxes on alcohol and enforcing bans on alcohol advertising;
• reducing salt intake;
• replacing trans-fats in foods with polyunsaturated fats;
• promoting public awareness about diet and physical activity; and
• delivering hepatitis B vaccinations.
Of course, lifestyle plays only so much of a role, says Dr. Anderson. "In general, a healthful diet and exercise is good for what ails you, and it helps in cancer as well," he says. "But not all cancers are preventable—and many are not," which is why "early detection leads to better outcomes."