Dr. Anil K. Chaturvedi, of the Infections and Immunoepidemiology Branch at the National Cancer Institute in Maryland, points out that though it has been known that the risk of HPV-associated cancers is higher among people with AIDS, the extent to which HIV-related immunosuppression plays a role is unclear.
He and his colleagues used data from a cancer registry for almost 500,000 persons diagnosed with AIDS between 1980 and 2004 to estimate risks for HPV-associated cancers. These include cancers of the anus, cervix, oropharynx, penis, vagina, and vulva.
The researchers also evaluated the relationship between immunosuppression and incidence of these cancers by counting CD4 T-cells at AIDS onset. Incidence was compared across three periods-1980, 1990, and 1996.
They found that people with AIDS had a statistically significant higher risk for all HPV-associated cancers.
It may be recalled that highly active antiretroviral therapy was introduced in 1996.
Revealing their findings, the researchers said that from 1996 through 2004, a low CD4 T-cell count was associated with an increased risk of invasive anal cancer among men.
The researchers said that the risk was higher in 1996 than in 1990. Both increases in risk were statistically significant, they added.
"Given that individuals currently infected with HIV may obtain little benefit from available HPV vaccines...our results underscore the need for effective screening for cervical cancer and anal cancer among persons with HIV infection or AIDS," the authors write.
In an accompanying editorial, Dr. Howard D. Strickler, of Albert Einstein College of Medicine, Department of Epidemiology and Population Health, said that the study provided novel evidence associating HPV-related invasive cancers with the level of immunosuppression in HIV-positive patients.
However, he also warned that despite being highly suggestive, the available data to date collectively still fell short of proving a biological relationship between HIV/AIDS and HPV-related cancers.
Mentioning several important strengths to Chaturvedi's study, Dr. Strickler said: "Nonetheless, it must additionally be acknowledged that these associations between human papillomavirus-related cancers and markers of immunosuppression were of moderate strength, varied between cancer types, and await confirmation."
A research article describing the study has been published online in the Journal of the National Cancer Institute.