Since the beginning of the HIV epidemic, cancer has figured prominently in the spectrum of immunodeficiency-related manifestations. The purpose of the National Cancer Institute’s HIV/AIDS Cancer Match Study is to examine the patterns of cancer risk among HIV-infected people. These data are valuable to researchers, public health authorities, and clinicians.

In the U.S., both HIV/AIDS and cancer are reportable by clinicians and healthcare facilities to state public heath authorities. The HIV/AIDS Cancer Match Study is based on a series of computerized linkages between the databases (termed “registries”) that are maintained by these authorities. The National Cancer Institute receives only anonymized data from these registries.

The HIV/AIDS Cancer Match Study is the largest study of cancer in HIV-infected people. The National Cancer Institute uses these study data to determine the spectrum of cancers that occur in HIV-infected people. The risk of cancer in HIV-infected people is compared with that in the general population to determine which cancers arise more frequently than expected. Investigators compare different groups of HIV-infected people, to determine whether certain individuals are at especially high risk of cancer. Through frequent updates of the data, investigators also monitor changing trends in cancer risk over time.

Three cancers are considered AIDS-defining conditions by the U.S. Centers for Disease Control and Prevention. These cancers are Kaposi sarcoma, which is caused by infection with human herpesvirus 8; non-Hodgkin lymphoma, which in many cases is caused by Epstein Barr virus; and cervical cancer, which is caused by human papillomavirus. HIV infection increases the risk of these cancers by causing weakening of the immune system’s control of the cancer-causing viruses. With the advent of highly active antiretroviral therapy (HAART) and better control of HIV, the risk of Kaposi sarcoma and non-Hodgkin lymphoma in HIV-infected people in the U.S. has declined.

HIV-infected people also have an elevated risk of certain other cancers, which is partly due to weakened immunity and partly due to the frequent presence of other cancer-causing viruses or exposures to tobacco and alcohol. Specifically, the other major cancers where HIV-infected people have a high risk include lung cancer (caused by tobacco), anal cancer (caused by human papillomavirus), liver cancer (caused by hepatitis B and C viruses, and alcohol abuse), and Hodgkin lymphoma (caused by Epstein Barr virus).