A substantially higher risk of anal carcinoma following the development of anogenital warts was seen among adults living with HIV and being treated in Washington, DC.
Adults living with HIV and receiving treatment at 14 clinics in Washington, DC, were found to have a risk of anal carcinoma after developing anogenital warts that was almost 13 times greater compared with those who did not develop anogenital warts, reports JAMA Dermatology.
“In the United States, incidence of and mortality due to anal carcinoma are rising faster than for most other cancers,” the authors explained. “Identifying populations who have a higher risk of developing anal cancers is critical to target preventive interventions.” Persons living with HIV are especially vulnerable due to their compromised immune systems, they added.
There were at least 18 months of follow-up in this longitudinal cohort study, for which data were collected between January 1, 2011, and March 31, 2017, on 6515 participants from the District of Columbia Cohort Longitudinal HIV Study (72.4% male at birth; mean [SD] age, 49.9 [12.7] years). Instances of anogenital warts and anal carcinoma were identified using International Classification of Diseases, Ninth Revision or International Statistical Classification of Diseases and Related Health Problems,Tenth Revision diagnosis codes.
Overall, cases of anal carcinoma were seen in 5.9% (n = 383) of the study participants during the study period. A stark difference in risk was seen between those with and without a history of anogenital warts. Of those with an anogenital warts history, 4.4% eventually developed anal carcinoma compared with just 0.3% (P < .001) of participants without the history.
Results after adjusting for covariates mirror these results in that the cohort with an anogenital warts history had 12.79 greater odds (95% CI, 6.19-26.45; P < .001) of developing anal carcinoma.
Low-risk types of human papillomavirus (HPV) frequently cause anogenital warts, in the presence of persistent infection, while high-risk persistent HPV has been linked to anogenital squamous cell carcinomas—of which the incidence and related mortality are on the rise. There is also potential for anal cancer to surpass cervical cancer as “the leading HPV-related cancer in older women,” the authors noted, “emphasizing the importance of better understanding the epidemiological risk factors for anal neoplasia.”
For example, 8% greater odds of developing anal carcinoma were seen per year of living with HIV (adjusted odds ratio, 1.08; 95% CI, 1.03-1.14; P = .003).
Their analysis also found that younger males (aged 18-34 years), participants with a CD4 nadir below 200/mcL, and men who have sex with men were more likely to develop anogenital warts. Adjusting for race/ethnicity, years living with HIV, years on antiretroviral therapy, and smoking history did not affect risk.
“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 authors concluded. “Clinicians should counsel individuals living with HIV who have anogenital warts on this risk.”
In addition, they highlight, at present, the ANCHOR study is evaluating the effectiveness of anal cancer screening and topical or ablative treatments in adults living with HIV.
Arnold JD, Byrne ME, Monroe AK, Abbott SE; District of Columbia Cohort Executive Committee. The risk of anal carcinoma after anogenital warts in adults living with HIV. JAMA Dermatol. Published online January 13, 2021. doi:10.1001/jamadermatol.2020.5252