Background

Men who have sex with men (MSM) are at elevated risk of having anal cancer. However, the prevalence and incidence among MSM of high-grade anal intraepithelial neoplasia (HGAIN), the putative precursor of anal cancer, is understudied, particularly in Asians.

Methods

A total of 123 HIV-positive and 123 HIV-negative MSM were enrolled at the Thai Red Cross AIDS Research Centre in Bangkok, Thailand, and followed for 12 months. Anal sample collection for human papillomavirus (HPV) genotyping and high-resolution anoscopy (HRA) with biopsies were performed at every visit.

Results

Mean age at enrollment was 28.9 years. HIV-positive MSM were more commonly infected with high-risk HPV types in the anus than HIV-negative MSM (57.5 vs. 36.6%; P  =  0.001). The prevalence of HGAIN was 18.9% in HIV-positive and 11.4% in HIV-negative MSM (P  = 0.1). The incidence of HGAIN at 12 months was 29% in HIV-positive and 8% in HIV-negative MSM (P  =  0.001). The hazard ratios for incident HGAIN in multivariate models were 5.16 [95% confidence interval (CI) 1.89-14.08, P  < 0.001] in MSM with persistent HPV 16 and/or 18 infection and 2.62 (95% CI 1.04-6.61, P  =  0.042) in HIV-positive MSM.

Conclusions

Approximately one-third of HIV-positive MSM developed incident HGAIN within 12 months. Given the relative increased prevalence of HIV among MSM worldwide, local HGAIN data are needed to guide practitioners, policy makers, and communities in planning for strategies to screen for and treat HGAIN in this population.

Background

HIV-positive men who have sex with men (MSM) have a higher prevalence of anal human papillomavirus (HPV) infection and anal cancer incidence than HIV-negative MSM. High-risk HPV persistence is an important risk factor for the development of anal cancer.

Methods

A total of 123 HIV-positive and 123 HIV-negative MSM were enrolled from the Thai Red Cross AIDS Research Centre in Bangkok, Thailand, and followed for 12 months. Anal sample collection for HPV genotyping was performed at every visit. HPV prevalence, incidence, clearance, and persistence were calculated. A logistic regression model was used to study factors associated with high-risk HPV persistence.

Results

The prevalence of any anal HPV infection was 85% in HIV-positive and 58.5% in HIV-negative MSM (P < 0.0001). The prevalence of high-risk HPV infection was 57.5% in HIV-positive and 36.6% in HIV-negative MSM (P = 0.001). HPV 16 was the most common high-risk HPV type. HIV-positive MSM had a higher prevalence (22.5% vs. 9.8%, P = 0.008) and persistence (16.7% vs. 1.3%, P < 0.001) of HPV 16 than HIV-negative MSM and a trend for higher incidence (16.1 vs. 6.1 episodes/1000 person-months, incidence rate ratio 2.6, P = 0.058). HIV infection (odds ratio: 4.45, 95% confidence interval: 2.11 to 9.4, P < 0.001) and smoking in HIV-positive MSM (odds ratio: 2.3, 95% confidence interval: 1.17 to 4.5, P = 0.015) were independently associated with high-risk HPV persistence in multivariate models.

Conclusions

In addition to targeting HIV-positive MSM who are at higher risk for anal, high-risk HPV persistence, anal cancer prevention programs should also integrate behavioral interventions such as smoking cessation to modify risk for high-risk HPV persistence.