Antiretroviral therapy may prevent some cancers in people with HIV

In people infected with human immunodeficiency virus (HIV), highly active antiretroviral therapy (HAART) may prevent most excess cases of Kaposi sarcoma and non-Hodgkin lymphoma, according to a new study in the March 16 issue of the Journal of the National Cancer Institute.

Studies of people with acquired immunodeficiency syndrome (AIDS) have reported increased risks of several cancers, including Kaposi sarcoma, non-Hodgkin lymphoma, and, to a lesser extent, anal cancer, invasive cervical cancer, and Hodgkin lymphoma. However, less well understood are the associations of these cancer risks with the use of HAART, with immune status, and with behavioral risk factors such as smoking.

To estimate excess cancer risk in people infected with HIV and investigate the modifying effects of the use of HAART and behavioral factors on this cancer risk, Gary M. Clifford, Ph.D., of the International Agency for Research on Cancer in Lyon, France, and colleagues analyzed data from the Swiss HIV Cohort Study and Swiss cancer registries on more than 7,300 people infected with HIV.

People with HIV in the study had a highly elevated risk of Kaposi sarcoma and non-Hodgkin lymphoma. They also had an increased risk of anal cancer, Hodgkin lymphoma, cervical cancer, liver cancer, cancer of the lip, mouth, and pharynx, and non-melanoma skin cancer. People who used HAART had lower risks of Kaposi sarcoma and non-Hodgkin lymphoma compared with those who did not use HAART, although even with HAART these tumors occurred 20 times more frequently than they do in the general population without HIV/AIDS. HAART use was not associated with lower risks of Hodgkin lymphoma or other cancers. Although people infected with HIV had increased risks of cancers of the lung, lip, mouth, and pharynx, no cases of these cancers were found among nonsmokers.

"In conclusion, HAART treatment may prevent excess risk of [Kaposi sarcoma] and non-Hodgkin lymphoma, but not that of Hodgkin lymphoma or other non–AIDS-defining cancers," the authors write. "Focusing on ways to encourage persons infected with HIV to quit smoking would be effective in reducing lung cancer in these persons."

In an editorial, Eric A. Engels, M.D., and James J. Goedert, M.D., of the National Cancer Institute, revisit the history of the AIDS epidemic and how the knowledge of cancer and immune diseases has grown since it began. They note that questions remain about the types and severity of cancers that will appear in coming years among patients on HAART, who have less severe but prolonged immunosuppression. "Controlling the epidemic and ameliorating the suffering of persons living with HIV/AIDS are more urgent than ever," they write. "Continued study of cancer in people with HIV/AIDS will redound to give us clues about cancer etiology to the benefit of all."