Liver transplant recipients have a higher prevalence of anal squamous intraepithelial lesions

Background: Anal squamous intraepithelial lesions (ASIL) are precancerous lesions of anal squamous cell carcinoma, with a higher prevalence in immunosuppressed patients. There are some studies in kidney transplant recipients, but there is no information regarding prevalence in liver transplantation. Our aim was to evaluate the prevalence of ASIL in this setting. Methods: Prospective case-control study involving liver transplant recipients without any other known risk factor for ASIL (n = 59), which were compared with a healthy control group (n = 57). All were submitted to anal cytology and high-resolution anoscopy was performed in those with abnormal results. Results: Ten (17%) of liver transplant recipients had abnormal cytological results, seven patients had atypical squamous cells of undetermined significance (ASC-US), one patient had atypical squamous cells that cannot exclude high-grade (ASC-H) and two patients had high-grade squamous intraepithelial lesions (HSIL). In the control group, one patient (2%) had an ASC-US result (P = 0.005). Anal squamous intraepithelial lesions were confirmed in 7 out of 10 of liver transplant patients and 0 out of 1 in the controls (P = 0.013) by high-resolution anoscopy with biopsies. Current smoking was the only risk factor for abnormal cytology (odds ratio = 5.87, 95% confidence intervals = 1.22-28.12, P = 0.027). Conclusions: Liver transplant patients have a higher risk of ASIL. Screening should be considered, especially in smokers.