HIV-infected people have a higher risk for many cancers than do healthy people, largely as a result of HIV-related immunosuppression, which impairs control of oncogenic viral infections.1, 2, 3 A high prevalence of these infections and other cancer-risk factors (eg, smoking and alcohol use) contribute to the elevated risk.1, 2, 3, 4 Kaposi's sarcoma, some subtypes of non-Hodgkin lymphoma, and cervical cancer are caused by viruses (Kaposi sarcoma-associated herpesvirus, Epstein-Barr virus, and human papillomavirus, respectively) and are among conditions that can mark the onset of AIDS.3 HIV-infected people have elevated risks for these AIDS-defining cancers and other virus-related non-AIDS-defining cancers, but not for most virus-unrelated non-AIDS-defining cancers.1, 2, 3
After the introduction of effective antiretroviral therapy (ART) in 1996, the risks for AIDS and death decreased strikingly in HIV-infected people.3 The incidences of Kaposi's sarcoma and non-Hodgkin lymphomas have also decreased, but remain higher in HIV-infected people than in the general population; trends for other cancers are less clear.3, 5, 6, 7, 8, 9, 10, 11, 12 Few recent comprehensive population-based data exist about cancer risks for HIV-infected people.6, 8, 9, 10, 12
The risk for some types of cancers might continue to decline as ART regimens improve, treatment is initiated at earlier stages of HIV disease, and access to ART increases.13 However, treatment might not fully reverse the effect of early immune suppression, and immune dysfunction and chronic inflammation can persist among people receiving ART.2 HIV-infected people, including those who have not developed AIDS, might therefore still have an elevated risk of cancer. Furthermore, many cancer types have latency periods of decades, and the modern ART era is only 20 years old; elevated risks for some cancers might, therefore, emerge over time. Finally, with prolonged survival the HIV population is ageing, and the effect of HIV-related immunosuppression in an ageing population is unclear.10, 14 For these reasons, continued monitoring of cancer risks in this population is vital. In this study, we describe the range of cancer risks among HIV-infected people in the USA during the modern ART era by use of linked data from several population-based HIV and cancer registries.
Research in context
Evidence before this study
We searched PubMed for citations published in English during Jan 1, 2000, to Dec 31, 2016, with MeSH terms “cancer”, “incidence”, and “HIV infections”, reviewed personal collections of study reports and reviews, and examined reference lists of reviewed publications to identify publications about cancer risk in people with HIV, compared with the general population or uninfected groups. Specifically, we examined publications that reported risk estimates overall and by AIDS onset, and recent trends covering the era of effective antiretroviral therapy (ART) beginning in 1996. Evidence indicates that HIV-infected people, especially those with AIDS, have an elevated risk for many cancers, especially those from viral causes. Additionally, after the introduction of ART in 1996, the incidence of two AIDS-defining cancers, Kaposi's sarcoma and non-Hodgkin lymphoma, decreased. However, trends for other cancers are less clear, and there is a shortage of recent and comprehensive population-based data about cancer risks for people with HIV.
Added value of this study
The HIV/AIDS Cancer Match (HACM) Study is the largest population-based study of cancer in HIV-infected people. We used data from the study to assess the risk of cancers in a sample of 448 258 people with HIV in the USA during 1996–2012. We found that, compared with the general population, HIV-infected people (including those without AIDS) had a greater risk for various cancers, including AIDS-defining cancers, many other virus-related cancers, and lung cancer. Although the risk for Kaposi's sarcoma, non-Hodgkin lymphoma, and some non-AIDS-defining cancers (anus, liver, and lung) decreased over time, risks generally have remained high.
Implications of all the available evidence
The decreases in cancer risk in people with HIV over time probably reflect the sustained and widened use of ART. Despite these decreases, however, cancer risks in HIV-infected people have remained elevated during the modern treatment era, indicating that continued cancer control efforts are warranted with additional efforts aimed at cancer prevention and screening.