Factors associated with anal cancer screening follow-up by high-resolution anoscopy

High-resolution anoscopy (HRA) is a potential screening method for detection of anal cancer precursors. We evaluated factors associated with adherence to recommended HRA follow-up time intervals among men who have sex with men (MSM).

We employed a retrospective, observational cohort study with 155 MSM screened by HRA between 1 April 2011 and 31 March 2016 at a Federally Qualified Health Centre in Boston, Massachusetts.

The sample was 80% white, with a median age of 48 (non-normal distribution, IQR 15). All patients were assigned male sex at birth and none identified as transgender. Fifty patients (32%) followed up with a HRA appointment within 6 months of previous HRA detection of anal high-grade squamous intraepithelial lesion (HSIL). Among patients, 112 (72%) were HIV infected, 56 (36%) had a syphilis diagnosis during the study period, 89 (57.4%) had initiated Hepatitis A or B vaccination series, 70 (45.2%) accessed case management services and 19 (12.3%) utilised pre-exposure prophylaxis (PrEP). In bivariate analysis, patients who underwent recommended follow-up HRA within 6 months of HSIL diagnosis were less likely to report: case management utilisation (p=0.023), initiation of Hepatitis A or B vaccination (p=0.047), HIV diagnosis (p<0.001) and syphilis diagnosis (p=0.001), but were more likely to use HIV PrEP (p<0.001). In binomial logistic regression modelling after adjusting for age and race/ethnicity, patients who had follow-up with HRA within a recommended period of 6 months after HSIL diagnosis were less likely to have initiated Hepatitis A or B vaccination (adjusted OR 0.43, 95% CI 0.20 to 0.94), more likely to use PrEP (adjusted OR 4.47, 95% CI 1.30 to 15.49) and less likely to have a syphilis diagnosis (adjusted OR 0.34, 95% CI 0.14 to 0.86).

Three-quarters of patients with HSIL did not have follow-up HRA within the clinic's recommended follow-up period of 6 months following HSIL diagnosis by HRA. Future studies ought to explore whether addressing anal health during other STI-related care helps improve adherence to recommended time intervals for follow-up HRA. Given the high prevalence of STI and PrEP use, studies might also evaluate whether integrating HRA follow-up with other sexual health screenings helps improve adherence to recommended HRA follow-up.