HIV-positive men had almost a tripled chance of progression to grade 3 anal intraepithelial neoplasia (AIN) compared with HIV-negative men in a 574-person analysis. Lower nadir CD4 count made progression to grade 3 AIN even more likely.
High-grade anal intraepithelial neoplasia (HGAIN), which may progress to anal cancer, develops in many men who have sex with men (MSM) with and without HIV. To measure progression to and spontaneous regression of HGAIN, researchers conducted this retrospective analysis of patients attending St. Vincent's Hospital Anal Cancer Screening Clinic in 2004-2011, when HGAIN was not routinely treated.
The investigators defined HGAIN as a composite of histologically confirmed grade 2 or 3 anal intraepithelial neoplasia (AIN2/3) and/or high-grade squamous intraepithelial lesion on anal cytology.
The study involved 574 patients, 570 of them (99.3%) men. Median age stood at 45 years (interquartile range [IQR] 36 to 51), and 73% of patients had HIV infection for a median of 13.8 years (IQR 6.4 to 19.8). Among people with HIV, median CD4 count stood at 500 cells/μL (IQR 357 to 662), and 83.5% had an undetectable viral load.
Through a median follow-up of 1.1 years (IQR 0.26 to 2.76), progression to HGAIN measured 7.4 per 100 person-years (95% confidence interval [CI] 4.73 to 11.63), meaning about 7 of 100 men had progression each year. Statistical analysis could identify no risk factors for progression to HGAIN.
