Not only are people living with HIV more likely to be diagnosed with a cancer not typically associated with AIDS, but they are also more likely to be diagnosed with a malignancy at a younger age. These are the sobering findings of a study conducted in Atlanta and reported Wednesday, July 21, at the XVIII International AIDS Conference in Vienna.
As people with HIV survive longer, due to the widespread use and effectiveness of antiretroviral (ARV) therapy, diseases with long latency periods—notably non-AIDS cancers and cardiovascular disease—are emerging. In fact, according to another study reported in Vienna by U.S. Centers for Disease Control and Prevention epidemiologists, the number of non-AIDS cancers now rival the number of AIDS-related cancers in people living with HIV and is expected to grow substantially in coming years.
Of central concern are the results of various studies conducted over the past 10 years indicating that people living with HIV may, in fact, be at a higher risk for various non-AIDS-related cancers than those not infected with HIV. According to Minh Ly Nguyen, MD, of Emory University School of Medicine in Atlanta, studies have found an increase in the incidence of anal/rectal cancer, liver cancer, Hodgkin’s lymphoma, lung cancer and head/neck cancer.
Studies have also suggested that people with HIV are developing these cancers at an earlier age, though the data have been mixed or inconclusive. In turn, Nguyen’s group set out to investigate both the incidence of non-AIDS cancers and the age at diagnosis at an urban HIV clinic in the Southeast of the United States: the Grady Infectious Disease Program at the Ponce de Leon Health Center in Atlanta.
The study conducted by Nguyen’s team was a retrospective analysis of 8,300 people living with HIV being cared for at the clinic between 2000 and 2007. The average age of the male and female patients, upon starting care at the clinic, was 40 and 39, respectively. The majority of the patients were black—73 and 88 percent, respectively.
A total of 512 cancers were diagnosed between 2000 and 2007. Of those cancers, 192 were non-AIDS defining; 320 were AIDS related.
The most common non-AIDS malignancy was lung cancer, documented in 40 patients. This was followed by anal/rectal cancer (24), head/neck cancer (22), prostate cancer (18), Hodgkin’s lymphoma (16), breast cancer (11) and liver cancer (10); 51 other cancers were also documented.
Kaposi’s sarcoma, non-Hodgkin’s lymphoma and cervical cancer accounted for the vast majority of AIDS-defining malignancies.
The average age at the time of a cancer diagnosis was 47 among the male patients and 48 among the female patients. About 52 percent of the men were receiving ARV treatment at the time of their cancer diagnosis, compared with 40 percent of women. Most disturbing, only 17 percent of the men and 11 percent of the women had undetectable viral loads at the time their cancers were documented.
Compared with health data for the Atlanta metropolitan area involving people not infected with HIV, anal/rectal cancer was 67 times more likely to be diagnosed in Ponce de Leon clinic patients. Hodgkin’s lymphoma was 19.7 times more likely to be diagnosed, the incidence of head/neck cancer was 8.7 times higher, and the rate of lung cancer was 4.5 times higher. All of these increased rates were statistically significant, meaning that the differences observed between the HIV-positive patients and those in the general population were too great to have occurred by chance.
Rates of breast cancer were similar between the two groups, whereas prostate cancer occurred less frequently among HIV-positive patients compared with those in the general population.
Significant age differences were also observed by Nguyen’s group. Whereas the average age of anal/rectal cancer diagnosis is 55 in the general Atlanta population, it was 41 in the Ponce de Leon clinic patients—a difference of 14 years. For liver cancer, the difference was 16 years, with an average diagnosis age of 60 in the general population and 44 in the HIV-positive population. Lung cancer was typically diagnosed around 66 years of age in the general population, compared with 52 years of age in the HIV-positive population.
While breast cancer and prostate cancer rates may not have differed between the two groups, people living with HIV were more likely to be diagnosed at younger ages: 45 versus 58, and 53 versus 64, respectively.
Hodgkin’s disease was the only cancer not shown to be diagnosed among people living with HIV at a younger age.
While these data are compelling, Nguyen noted that the study suffers from several limitations. As it was retrospective in design—it simply reviewed patients’ medical records—data were missing, the researchers were unable to follow up with intriguing questions, or to control for individual risk factors such as smoking and other cancer risk factors.
Nguyen’s team concluded, however, that non-AIDS cancers do appear to be occurring at an earlier age, at least among the Ponce de Leon patients. “Cancer screening in HIV-infected patients should be considered at an earlier age than in the general population,” she said.