Risk of human papillomavirus (HPV)-associated cancers is greater for people living with AIDS and increases with increasing immunosuppression, according to a new study published online July 31 in the Journal of the National Cancer Institute.
Although the risk of HPV-associated cancers is known to be higher among people with AIDS, the extent to which HIV-related immunosuppression plays a role is unclear.
Anil K. Chaturvedi, Ph.D., of the Infections and Immunoepidemiology Branch at the National Cancer Institute, in Rockville, Md., and 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).
People with AIDS had a statistically significant higher risk for all HPV-associated cancers. From 1996 (when highly active antiretroviral therapy was introduced) through 2004, a low CD4 T-cell count was associated with an increased risk of invasive anal cancer among men. This risk was higher in 1996 than in 1990. Both increases in risk were statistically significant.
"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, Howard D. Strickler, M.D., of Albert Einstein College of Medicine, Department of Epidemiology & Population Health, said the study provides novel evidence associating HPV-related invasive cancers with the level of immunosuppression in HIV-positive patients. However, he also cautioned that while highly suggestive the available data to date collectively still fall short of proving a biological relationship between HIV/AIDS and HPV-related cancers. Regarding the study by Chaturvedi et al, for example, after mentioning several important strengths to that study, Dr. Strickler also mentions:
"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."
Source: Journal of the National Cancer Institute (news : web)