Inflammatory Bowel Disease and the Risk of Anal Squamous Intraepithelial Lesions and Anal Cancer in Men Who Have Sex With Men.

Background: The risk of anal cancer is increased in patients with human immunodeficiency virus (HIV), inflammatory bowel disease (IBD), and among men who have sex with men (MSM). High grade squamous intraepithelial lesions (HSILs) are precursor lesions to anal squamous cell carcinoma (SCC), and treatment of these lesions can decrease progression to anal SCC. This study aims to determine the prevalence of HSIL and anal cancer among MSM patients with and without IBD referred for anal cancer screening.

Methods: This is a retrospective study of all MSM patients seen at an anal squamous intraepithelial lesions (aSILs) and anal cancer screening specialty clinic. Data were manually and electronically collected from clinical documentation and pathology results for the primary outcomes of HSIL and anal cancer. Demographics, HIV status, IBD disease status, disease phenotype, and immunosuppressive medication use were collected through the electronic health record. Descriptive statistics were used.

Results: In all, 4623 patients were included for analysis. Among 57 MSM patients with IBD, 25 (43.9%) had a history of HSIL, and 2 (3.5%) had a history of anal cancer. Among 4618 MSM patients without IBD, 2417 (52.3%) had a history of HSIL, and 139 (3.0%) had a history of anal cancer (P = .744). Rates of HIV were 49.1% among MSM patients with IBD and 69.8% among MSM patients without IBD (P = .001). There remained no difference in prevalence of HSIL and anal cancer between groups when adjusting for HIV status. Among IBD patients, only 21.6% were referred for screening by their gastroenterologist.

Conclusions: Among MSM with and without IBD, both groups had an equally high prevalence of HSIL and anal SCC. Awareness of appropriate surveillance to identify aSIL in MSM patients with IBD is needed among gastroenterologists.