Global burden of cancers attributable to infections in 2012: a synthetic analysis

Infections with certain viruses, bacteria, and parasites are strong risk factors for specific cancers. As new cancer statistics and epidemiological findings have accumulated in the past 5 years, we aimed to assess the causal involvement of the main carcinogenic agents in different cancer types for the year 2012.

We considered ten infectious agents classified as carcinogenic to human beings by the International Agency for Research on Cancer. We calculated the number of new cancer cases in 2012 attributable to infections by country, by combining cancer incidence estimates (from GLOBOCAN 2012) with estimates of attributable fraction (AF) for the infectious agents. AF estimates were calculated from the prevalence of infection in cancer cases and the relative risk for the infection (for some sites). Estimates of infection prevalence, relative risk, and corresponding 95% CIs for AF were obtained from systematic reviews and pooled analyses.