Infectious diseases account for one-fifth of cancer deaths each year
MedWire News: Study findings show that infections with certain viruses, bacteria, and parasites are responsible for every one in five deaths due to cancer each year.
"Many infection-related cancers are preventable, particularly those associated with human papillomavirus (HPV), Helicobacter pylori, and hepatitis B (HBV) and C (HCV)," say Martyn Plummer (International Agency for Research on Cancer, Lyon, France) and colleagues, adding that these infections could be responsible for 1.9 million cancer cases, most of which are gastric, liver, and cervical cancers.
Using data on estimated cancer incidence in 2008, the researchers calculated the population-attributable fraction (PAF) for infectious agents classified as carcinogenic to humans by the International Agency for Research on Cancer. This allowed the team to identify the proportion of new cancer cases in the population that could have been prevented by an intervention.
Of the estimated 12.7 million new cancer cases identified worldwide, around 2 million were attributable to infections (PAF=16.1%), of which 1.6 million (80%) occurred in less-developed regions.
When the researchers looked into the potential causative infectious agents, they found that HPV, H. pylori, and HBV/HCV accounted for 1.9 million cancer cases worldwide, at PAFs of 30.0%, 32.5%, and 29.5%, respectively.
Analysis of the data according to geographic region showed that, overall, 16.1% of cancer cases in 2008 were attributable to infection, with the highest PAF seen in less-developed countries (22.9%) relative to more-developed countries (7.4%). Furthermore, the PAF was found to vary greatly between regions, from 3.3% in Australia and New Zealand to 32.7% in sub-Saharan Africa.
Cervical cancer accounted for half of the infection-related burden of cancer in women, and in men liver and gastric cancers accounted for over 80%, the team reports in The Lancet Oncology.
In an associated commentary, Goodarz Danaei (Harvard School of Public Medicine, Boston, Massachusetts, USA) says: "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."
The researchers conclude: "Since infections are an important and preventable cause of cancer worldwide, clinicians should support the implementation of available strategies for prevention ‑ ie, vaccination against HBV and HPV, use of safe injection practices, and avoidance of parenteral treatment when oral treatment is available."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Ingrid Grasmo