People with HIV were nearly 13 times as likely to develop anal cancer if they had a history of anal or genital warts. These findings were particularly pronounced in people with a history of AIDS, meaning a lowest-ever CD4 count of 200 or less.
Published this week in JAMA Dermatology, the findings come at a time when few clinicians are trained in how to do anal screening and follow-up exams, called high-resolution anoscopy, to detect anal cancer early.
Human papillomavirus (HPV), a common sexually transmitted infection, can cause anal and genital warts, precancerous cell changes known as dysplasia or neoplasia and anal, cervical and several other types of cancer. Best known as a screening method for cervical cancer, Pap tests can also detect abnormal anal cell changes at an early, more treatable stage. HPV vaccination can prevent warts and precancerous changes.
Anal cancer is on the rise in the United States, including among people living with HIV. The HIV Medical Association recommends that people with HIV, a history of receptive anal sex (bottoming) or a history of anal or genital warts receive anal Pap tests to detect HPV-related abnormalities. Multiple international studies have shown that routine anal screening for people with HIV is associated with lower anal cancer rates. But the Centers for Disease Control and Prevention is waiting for the results of the Anal Cancer HSIL Outcomes Research (ANCHOR) trial to determine how and when to screen for and follow up on anal abnormalities.
It is still unclear whether such individuals may benefit from digital anorectal exams, anal Pap tests or high-resolution anoscopy to screen for anal neoplasia, wrote study authors Justin Arnold, MD, of the University of California, Riverside, and colleagues.
Lack of anal screening guidelines were associated with long delays in follow-up anoscopy, which is analogous to colposcopy for cervical cancer, according to a report in Medscape.
The study followed 6,515 adults with HIV treated at 14 clinics in Washington, DC, from 2011 to 2017. In this cohort, 72% were men, and 28% were women. More than three quarters were Black, and the median age was about 50.
Of the total cohort, 383 participants (6%) were diagnosed with anal or genital warts. These people were more likely to be men, to be between ages 18 and 34 and to have had a lowest-ever CD4 count of 200 or less. And while gay and bisexual men made up the majority of those with anal cancer, at 54%, a large minority weren’t. Only 4% of participants received an anal Pap test during the study.
While only 4% of people with a history of warts developed anal cancer, that was still 13 times higher than their peers who’d never had anal or genital warts during the study (0.3%). People with a lowest-ever CD4 count of 200 or less were six times more likely to develop anal cancer, whether they’d had warts or not. What’s more, for every additional year a person had lived with HIV, the risk of developing anal cancer increased by 8%.
“These findings suggest that adults living with HIV who have a history of anogenital warts have a substantially increased risk of developing anal carcinoma,” the study authors wrote. “Clinicians should counsel individuals living with HIV who have anogenital warts on this risk.”
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