Progression From Perianal High-Grade Anal Intraepithelial Neoplasia to Anal Cancer in HIV-Positive Men Who Have Sex With Men

BACKGROUND: High-grade intraepithelial neoplasia is known to progress to invasive squamous-cell carcinoma of the anus. There are limited reports on the rate of progression from high-grade intraepithelial neoplasia to anal cancer in HIV-positive men who have sex with men. OBJECTIVES: The purpose of this study was to describe in HIV-positive men who have sex with men with perianal high-grade intraepithelial neoplasia the rate of progression to anal cancer and the factors associated with that progression. DESIGN: This was a prospective cohort study. SETTINGS: The study was conducted at an outpatient clinic at a tertiary care center in Toronto. PATIENTS: Thirty-eight patients with perianal high-grade anal intraepithelial neoplasia were identified among 550 HI V-positive men who have sex with men. INTERVENTION: All of the patients had high-resolution anoscopy for symptoms, screening, or surveillance with follow-up monitoring/treatment. MAIN OUTCOME MEASURES: We measured the incidence of anal cancer per 100 person-years of follow-up. RESULTS: Seven (of 38) patients (18.4%) with perianal high-grade intraepithelial neoplasia developed anal cancer. The rate of progression was 6.9 (95% CI, 2.8-14.2) cases of anal cancer per 100 person-years of follow-up. A diagnosis of AIDS, previously treated anal cancer, and loss of integrity of the lesion were associated with progression. Anal bleeding was more than twice as common in patients who progressed to anal cancer. LIMITATIONS: There was the potential for selection bias and patients were offered treatment, which may have affected incidence estimates. CONCLUSIONS: HIV-positive men who have sex with men should be monitored for perianal high-grade intraepithelial neoplasia. Those with high-risk features for the development of anal cancer may need more aggressive therapy.