The global health burden of infection‐associated cancers in the year 2002

Abstract

Several infectious agents are considered to be causes of cancer in humans. The fraction of the different types of cancer, and of all cancers worldwide and in different regions, has been estimated using several methods; primarily by reviewing the evidence for the strength of the association (relative risk) and the prevalence of infection in different world areas. The estimated total of infectionattributable cancer in the year 2002 is 1.9 million cases, or 17.8% of the global cancer burden. The principal agents are the bacterium Helicobacter pylori (5.5% of all cancer), the human papilloma viruses (5.2%), the hepatitis B and C viruses (4.9%), Epstein-Barr virus (1%), human immunodeficiency virus (HIV) together with the human herpes virus 8 (0.9%). Relatively less important causes of cancer are the schistosomes (0.1%), human Tcell lymphotropic virus type I (0.03%) and the liver flukes (0.02%). There would be 26.3% fewer cancers in developing countries (1.5 million cases per year) and 7.7% in developed countries (390,000 cases) if these infectious diseases were prevented. The attributable fraction at the specific sites varies from 100% of cervix cancers attributable to the papilloma viruses to a tiny proportion (0.4%) of liver cancers (worldwide) caused by liver flukes. ' 2006 Wiley-Liss, Inc.

Relationship between current level of immunodeficiency and non‐acquired immunodeficiency syndrome‐defining malignancies

“…15 In addition, studies have found that vulva, vagina, penile, oral cavity, and pharynx cancers are caused by HPV, with limited association with cancer of the larynx. 11,21,25,35 Interestingly, previous studies have found a link between virus-related cancers such as HL, 27 HCC, 28 and anal cancer 26 with immunodeficiency determined by time to AIDS diagnosis 26,27 or CD4 count within 1 year of diagnosis. 28 The most common non-virus-related epithelial cancers (eg, lung and prostate) remain difficult to treat, and the majority remain incurable, with very little improvement in survival over the past decade 36 ; in addition, based on oncoepidemiologic studies, risk of epithelial cancers starts to increase at about the age of 30 years and increases progressively by age.…”

“…Nonmelanoma skin cancer was excluded, as it is not systematically ascertained and not thought to cause significant morbidity or mortality. 2 Virus-related cancers included all cancers whose development was known to be virus related, 11,25 including anal cancer, HL, and HCC. Non-virus-related epithelial cancer included all epithelial cancers that have not been shown to be related to a particular virus.…”

“…8 Several oncogenic viruses are thought to cause AIDS-defining malignancies; human herpesvirus 8 is associated with KS, Epstein-Barr virus (EBV) is associated with the 2 most common NHL subtypes, and the human papillomavirus (HPV) is associated with cervical cancer. [10][11][12] Also, several non-AIDS-defining malignancies have been associated with viruses, including HL, 13,14 anal cancer, 15 and hepatocellular carcinoma (HCC). 16 The increasing incidence of some non-AIDS-defining malignancies and the decrease in AIDS-defining malignancies in the cART era has meant that non-AIDS-defining malignancies now account for more morbidity and mortality in HIV-infected patients than AIDS-defining malignancies.…”

Prevention of cancer through immunization: Prospects and challenges for the 21st century

“…Their relative contribution is higher in the developing than in the developed world, with figures for the overall percentage of infectionattributable cancer ranging from 15-25% [1]. For each microorganism associated with cancer, persisting infection generally precedes cancer induction, though the incidence of persistent infection is much higher than that of the cancer.…”

“…A substantial proportion of the world's cancer burden can be attributed to the consequences of chronic infection with viruses, bacteria, and parasites [1]. While the mechanisms by which these infections promote cancer are diverse, a common denominator is that the cancers develop in the context of chronic infection.…”