Trends in Cancer Incidence in HIV-Infected Patients

April 18, 2014

A new study investigates the impact of epidemiologic factors on time trends for AIDS-defining and non–AIDS-defining cancers.

Patients with HIV infection are at a higher risk for both AIDS-defining cancers (ADCs), such as Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer, and non–AIDS-defining cancers (NADCs). As the overall health and longevity of persons infected with HIV continue to improve through treatment with highly active antiretroviral medications, there has been a decline in some common AIDS-defining malignancies but also a rise in a number of NADCs. What factors might be responsible for changes in incidence and the relative magnitude of those changes were explored in a study just published in the journal AIDS.

Investigators used data from the HIV/AIDS Cancer Match (HACM), which links state HIV and cancer registries in HIV-infected people from several states. The HIV-associated relative risk of cancer was captured using the standardized incidence ratio (SIR), which is the ratio of observed to expected cancer cases (the latter derived from general population incidence rates). The investigators looked at data from 1996 to 2010 for 10 cancers (3 ADCs, 7 NADCs). The authors note that changes in the incidence of disease over time may reflect changes in 3 factors: HIV population demographic structure (eg, age distribution), background cancer rates, and HIV-associated relative risks.

The study showed a change in the SIR of many cancers during this period. Rates of Kaposi sarcoma, non-Hodgkin and Hodgkin lymphoma, and cervical and lung cancers decreased over time. There was an increase in the incidence of anal cancer in HIV-infected patients that was attributable to increasing background rates in the general population. Demographic shifts influenced several other trends. In general, falling relative risks largely explained ADC declines, while background incidence contributed to some NADC trends.

These results strongly suggest that availability of HAART has contributed to the declining incidence of many virus-related cancers but that the trends for different cancers differ by cancer site.

Primary care physicians should be aware of the increased risk of cancers in HIV-infected patients but also of the importance of HAART in decreasing the risk of AIDS-defining malignancies.

Reference:

Robbins HA, Shiels MS, Pfeiffer RM, Engels EA. Epidemiologic contributions to recent cancer trends among HIV-infected people in the United States. AIDS. 2014;28:881-890. doi: 10.1097/QAD.0000000000000163.