The nearly 900,000 people in the United States living with diagnosed human immunodeficiency virus (HIV) infection have an excess cancer risk of 50%, according to a joint analysis of data by the National Cancer Institute and the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention.
The reasons people with HIV infection have an increased cancer risk include immunosuppression, frequent coinfection with oncogenic viruses, and risk behaviors including smoking. The introduction of highly active antiretroviral therapy in 1996 has led to a decline in mortality related to acquired immunodeficiency syndrome (AIDS), but increased numbers of people living with HIV have resulted in an overall aging of the HIV population.
For the analysis, investigators “derived cancer incidence rates for the U.S. HIV-infected and general populations from Poisson models applied to linked HIV and cancer registry data and from Surveillance, Epidemiology, and End Results program data, respectively,” the authors explained in the Journal of the National Cancer Institute. “We applied these rates to estimates of people living with diagnosed HIV at mid-year 2010 to estimate total and expected cancer counts, respectively. We subtracted expected from total cancers to estimate excess cancers.”
At mid-year 2010, an estimated 859,522 people were living with diagnosed HIV infection in the United States, 39.1% for 5 or more years. Most were aged 40 to 59 years, and 74.9% were male, predominantly men who have sex with men.
Among the estimated 7,760 cancers occurring among HIV-infected people, 3,920 cancers “were in excess of expected,” the investigators stated. “The most common excess cancers were non-Hodgkin lymphoma (NHL; n = 1,440 excess cancers, occurring in 88% excess), Kaposi’s sarcoma (n = 910, 100% excess), anal cancer (n = 740, 97% excess), and lung cancer (n = 440, 52% excess).”
The proportion of excess cancers that were AIDS-defining, such as Kaposi’s sarcoma, NHL, and cervical cancer) declined with age and time since AIDS diagnosis, but the incidence of some non–AIDS-defining cancers, such as lung and anal cancers, has increased.
“For anal cancer, 83% of excess cases occurred among men who have sex with men, and 71% among those living 5 or more years since the onset of AIDS. Among injection drug users, 22% of excess cancers were lung cancer, and 16% were liver cancer,” the authors noted. Lung and anal cancers “together represent 27% of the total excess, underscoring that the development of strategies for prevention and early detection of these cancers among HIV-infected people is warranted.”
Even though the incidence of AIDS-defining cancers declined, “14 years after the introduction of highly active antiretroviral therapy, over half of excess cancers were still AIDS-defining cancers,” the researchers pointed out. “This continuing excess illustrates that improvements in HIV treatment at the population level must remain a priority. Implementing measures to promote access and adherence to highly active antiretroviral therapy, especially targeted to young people and people with HIV only, could prevent many excess AIDS-defining cancers.”
The study was supported by the Intramural Research Program of the National Cancer Institute at the National Institutes of Health. ■
Robbins HA, et al: J Natl Cancer Inst 107:dju503, 2015.