The non-AIDS-defining malignancies included all forms of cancer except skin, lymphoma, cervical carcinoma, Kaposi's sarcoma and ill-defined cancers. Dr. Bedimo said the researchers examined anal, lung, melanoma, prostate, Hodgkin's and liver cancers all non-AIDS-defining individually.
Dr. Bedimo, chief of infectious disease at the Veterans Affairs North Texas Health Care System, said it's unclear exactly why non-AIDS-defining malignancies are more common in HIV patients than the general population. One controversial theory, he said, is that the anti-retroviral therapy itself might increase the risk of those cancers in HIV patients.
"The second hypothesis is that HIV-infected patients somehow, either by their lifestyle or other circumstances, are more subject to the traditional risk factors than non-HIV patients," he said. "The third hypothesis is that HIV or another undetected virus increases a patient's risk for developing cancer intrinsically."
Dr. Bedimo said that one major limitation of the study is the overrepresentation of males in the study. Males account for about 98 percent of the study population.
The next step is for researchers to examine other measures of immune function in patients with and without cancer.
"The hallmark of chronic HIV is a decline in CD4 T-cells, but we also know that HIV does a lot more to your immune system than just decrease the number of these cells," Dr. Bedimo said. "It's very possible that it is an immune dysfunction that impairs the cancer immune surveillance in patients even after their CD4 counts have increased."
|Contact: Kristen Holland Shear|
UT Southwestern Medical Center