Anal warts in men who have sex with men (MSM) often contain cancerous and precancerous cells, an “unsettling” finding of a study reported in the July 1 issue of Clinical Infectious Diseases. The authors indicate that simply treating anal warts isn’t enough among MSM—they should be surgically removed and tested for high-grade cells that can potentially cause serious disease. 

Anal warts are typically caused by two non-cancerous strains of the same virus: human papillomavirus (HPV) types 6 and 11. Because of the perceived low risk of serious disease, many people with anal warts avoid treatment or opt for less invasive ablation procedures, such as cryotherapy (freezing the warts) or laser removal.  

The new findings, reported by Hans Schlecht, MD, of Drexel University College of Medicine in Philadelphia and his colleagues, suggest that surgical removal may be necessary in order to test for pre-cancerous and cancerous clusters within the warts. These high-grade patches of cells are often caused by two cancerous HPV strains, types 16 and 18. 

The study conducted by Schlecht’s group was designed to look for hidden, or “occult,” pre-cancerous or cancerous cells in anal warts surgically removed from 320 MSM. Fifty percent of the men enrolled in the study were living with HIV.
About 34 percent of the men had anal warts containing pre-cancerous cells. In fact, 3 percent of the men were found to have anal cancer. 

The high-grade cells were more likely to be documented in the warts taken from the HIV-positive men—47 percent compared with 26 percent of the HIV-negative men in the study. What’s more, seven of the eight men in the study diagnosed with anal cancer were coinfected with HIV. 

Unfortunately, neither a high CD4 cell count nor an undetectable viral load appeared protective against pre-cancerous and cancerous lesions among the HIV-positive men in the study. CD4 cell counts averaged 431, and about 50 percent of the men had viral loads below the level of detection at the time the high-grade lesions were detected. 

“The present study demonstrates that, in a large urban population of MSM, condylomata [anal warts] requiring surgical excision frequently harbored occult high-grade anal intraepithelial neoplasia or anal squamous cell cancer,” the authors concluded. “These data emphasize the importance of obtaining tissue for histopathological examination in MSM presenting for treatment of anogenital condylomata. Prevention of recurrences and careful clinical follow-up of anal condylomata harboring high-grade anal intraepithelial neoplasia may be a method of anal cancer prevention in MSM, particularly in those with HIV infection.”