Some pathogens are a high risk factor for certain cancers: Of the 14 million new cancer cases in 2012, 2.2 million were due to ten pathogens. Most of these infection-related cancers affected poorer countries.
From the prevalence of infections in malignancy patients and the relative risk of infection for different countries, scientists at the IARC (International Agency for Research on Cancer) in Lyon analyzed how many cancer cases in 2012 were due to infection.
Of the eleven biological cancer triggers, the most common pathogens worldwide were in patients with newly diagnosed carcinomas:
- Helicobacter pylori (35.4%, 770,000 cases of gastric cancer).
- Human papillomavirus (HPV) (29.5%, 640,000 cases of cervical, penile, anal, vulvar, vaginal, oropharyngeal, oral cavity, and laryngeal cancer).
- Hepatitis B virus (HBV) (19.2%, 420 000 cases of liver cancer),
- Hepatitis C virus (HCV) (7.8%, 170 000 cases of liver and non-Hodgkin lymphoma).
These four pathogens alone explain two million of the 2.2 million cancers, or 92%, according to Martyn Plummer and Catherine de Martel of IARC. The remaining six are of secondary importance. The eleventh pathogen, HIV, was not included in the analysis.
Great potential through preventive measures
The study makes clear how strongly the respective risk of infection or cancer depends on the respective country and the living conditions of the people. In less developed regions, nearly a quarter of cancers are infection-related. Attributable Fraction (AF) ratios were highest in countries with the lowest Human Development Index (HDI) – and vice versa. The range is from less than 5% in the USA, Canada, Australia and New Zealand to over 40% in Mongolia and some African countries south of the equator. According to the study, there is great potential to reduce infection-related cancers with preventive measures such as vaccinations, safe injection techniques and remedies for bacteria.
Literature:
- Plummer M, et al: Global burden of cancers attributable to infections in 2012: a synthetic analysis.www.thelancet.com/lancetgh, Vol 4, September 2016.
InFo ONCOLOGY & HEMATOLOGY 2016; 4(6): 2
