HIV-infected people are at increased risk of cancers of infectious origin. We estimated the burden of cancer attributable to infections among HIV-infected people in the United States in 2008. Incidence rates for cancer sites associated with infections were estimated from record linkage between HIV/AIDS registries and cancer registries. Rates were applied to estimates of the population living with diagnosed HIV in the United States in 2008 to obtain the number of incident cancer cases. Site-specific attributable fractions and corresponding 95% confidence intervals (CIs) were estimated from infection prevalence among cancer cases. Infection prevalence data were derived from literature review of case series. Of an estimated 6200 incident cancer cases (95% CI 6000-6500), 2500 (95% CI 2400-2700) were attributable to infection (attributable fraction = 40%, 95% CI 39-42). The most important infections were Kaposi sarcoma herpes virus, Epstein-Barr virus, and human papillomavirus, which together were responsible for 2200 new cancer cases (95% CI 2100-2400), mainly Kaposi sarcoma, lymphomas, and ano-genital cancers. The attributable fraction in HIV-infected people was highest in the age group 20-29 years (69%, 95% CI 65-72). MSM were the HIV transmission group with the highest attributable fraction (48%, 95% CI 46-50), due to the high incidence of both Kaposi sarcoma and anal cancer. The very high fraction of cancer attributable to infection in HIV-infected people points to special opportunities to prevent these cancers, that is, avoidance, detection, and early treatment of cancer-associated infections, and universal early detection and uninterrupted treatment of HIV infection to avoid immunosuppression.
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