Men who have sex with men (MSM) living with HIV in France are commonly infected with a particular strain of human papillomavirus, known as HPV16, that is tied to a high risk of anal cancer. Of the numerous strains of HPV, HPV16 was the most commonly seen in this population in a recent study.
The HPV vaccine prevents various high-risk strains of the virus. However, in the United States it is recommended only for adolescents and young adults. So securing insurance coverage for the vaccine can be challenging for older individuals. The Centers for Disease Control and Prevention (CDC) advises that MSM up to age 26 receive the vaccine.
Publishing their findings in The Journal of Infectious Diseases, researchers from the French ANRS EP57 APACHES study examined 490 HIV-positive MSM age 35 or older (with a median age of 51) who were recruited between December 2014 and June 2016. The study did not include anyone who had anal cancer or who had been treated for high-grade anal intraepithelial neoplasia, or AIN, which is a precancerous lesion and a precursor to anal cancer, during the previous 12 months.
The investigators took a pair of anal swabs from the participants, one to test for signs of cancer and the other to look for different strains of HPV. Additionally, they gave each participant a digital rectal exam and also used high-resolution anoscopy, in which a tiny camera is inserted into the anus, to look for cancer-related abnormalities.
Seventy percent of the participants had at least one high-risk form of HPV. The most common high-risk strains included HPV16 (29 percent), HPV69 (16 percent) and HPV33 (13 percent).
Smoking was associated with a 1.8-fold greater likelihood of having a high-risk HPV strain, compared with not smoking. Those who were previously diagnosed with high-grade anal lesions, compared with those who had not been, had 4.5-fold greater odds of having HPV16 and 9.3-fold greater odds of having any high-risk HPV strain.
Of the 479 men for whom related results were available, a respective 1 percent and 7 percent had low- and high-grade anal cell changes. Forty-eight percent of the men had low-grade HPV-related disease (specifically, anal lesions), 15 percent had high-grade HPV-related disease and 37 percent did not have HPV-related disease. Of those who did not have HPV-related disease or who had a low-grade case, 19 percent had HPV16, compared with 63 percent of those with high-grade disease.
The study authors concluded: “Given the strong link between HPV16 and anal cancer, HPV prevalence can arguably be used as a proxy of higher probability of developing anal cancer.”
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To read the study abstract, click here.