The researchers found that, of the 12.7 million new cancer cases that occurred in 2008, the PAF for infectious agents was 16.1 percent. This represented about two million new cases. The fraction of infection-attributable cancers was higher in less developed countries than in more developed countries (22.9 versus 7.4 percent). Approximately 1.9 million cases of gastric, liver, and cervix uteri cancers were caused by Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses. Cervix uteri cancer accounted for about half of the infection-related burden of cancer in women, while liver and gastric cancers accounted for more than 80 percent in men. Younger people (<50 years) were affected by approximately 30 percent of infection-attributable cases.
"Around two million cancer cases each year are caused by infectious agents," the authors write. "Application of existing public health methods for infection prevention, such as vaccination, safer injection practice, or antimicrobial treatments, could have a substantial effect on the future burden of cancer worldwide."