Cancer Conundrum

The onset of three types of cancer'cervical cancer, Kaposi's sarcoma, and non-Hodgkin's lymphoma'are so common among HIVers with advanced HIV disease that they're considered AIDS-defining illnesses. But a new study shows HIVers'even those on effective antiretroviral therapy'also are more prone to several other types of cancer. In some cases, it was due to coinfection with other sexually transmitted diseases, but in others there was no exact discernable cause. For example, HIVers are 18 times more likely to develop Hodgkin's lymphoma; four times more likely to develop lung cancer; three times more likely to develop melanoma (skin cancer) and mouth and throat cancers; and about twice as likely to develop leukemia, colorectal, and kidney cancers, according to the study in the Annals of Internal Medicine. Why the increased cancer risks? The researchers theorize a weakened immune system may be less able to destroy newly formed cancerous cells before they take hold to become tumors or systemic infections. It's also possible that HIVers have higher rates of smoking and alcohol use, which can boost cancer risks, although the study did not screen for these factors.