Infections cause many cancers globally

Leading researchers, Catherine de Martel and Martyn Plummer from the International Agency for Research on Cancer in France declared: "Infections with certain viruses, bacteria, and parasites are one of the biggest and preventable causes of cancer worldwide...Application of existing public-health methods for infection prevention, such as vaccination, safer injection practice, or antimicrobial treatments, could have a substantial effect on future burden of cancer worldwide.The researchers performed a systematic evaluation to estimate the percentage of cancers worldwide that were caused by infections in eight regions. They calculated the population attributable fractions (PAF), i.e. the percentage of all new cancer incidents that could have been prevented through intervention on a specific exposure. They obtained data from various sources, including GLOBOCAN statistics that had estimated the incidence rates of 27 cancers in 184 countries, and calculated that in 2008 worldwide, about 16% of all cancers were linked to infections. The incidence rate of infection-related cancers in developing countries was almost three times higher, i.e. 22.9% in comparison with 7.4% in developed countries. The researchers noted a considerable difference in the fraction of infection-related cancers between different regions, ranging from 3.3% in Australia and New Zealand to 32.7% in sub-Saharan Africa. The researchers remark: "Many infection-related cancers are preventable, particularly those associated with human papillomaviruses (HPV), Helicobacter pylori, and hepatitis B (HBV) and C viruses (HCV)." They add that according to estimates, these four main infections together are responsible for 1.9 million cancer cases, the majority of which are gastric, liver, and cervical cancers, with cervical cancer accounting for about half of the infection related cancer burden in women, whilst liver and gastric cancers accounted for over 80% of cancers in men. The researchers conclude: "The 2011 UN high-level meeting on non-communicable diseases highlighted the growing global agenda for prevention and control of non-communicable diseases. [But] although cancer is considered a major non-communicable disease, a sizable proportion of its causation is infectious and simple non-communicable disease paradigms will not be sufficient." Goodarz Danaei from the Harvard School of Public Medicine in Boston in the U.S. writes in an accompanying comment: "Their estimates show the potential for preventive and therapeutic programs in less developed countries to significantly reduce the global burden of cancer and the vast disparities across regions and countries. Since effective and relatively low-cost vaccines for HPV and HBV are available, increasing coverage should be a priority for health systems in high-burden countries."