High-Resolution Anoscopy: A Crucial Tool for Timely Identification of High-Risk Anal Squamous Intraepithelial Lesions in Inflammatory Bowel Disease Patients

Background: Anal squamous intraepithelial lesions (ASIL) are premalignant lesions preceding squamous cell carcinoma (SCC). Early intervention is vital for prevention. Human papillomavirus (HPV) infection is a key risk factor. High-Resolution Anoscopy (HRA) aids in detection and monitoring. However, the early identification of precancerous anal lesions in inflammatory bowel disease (IBD) patients on immunosuppressive therapy remains understudied. This study emphasizes promptly identifying these lesions in IBD patients on immunosuppressive therapy, with a focus on the utility of HRA. Methods: A 29-year-old male, previously diagnosed with pancolonic Ulcerative Colitis (UC) and managed using anti-TNF pharmacotherapy, presented persistent chronic anal ulceration refractory to conservative medical interventions during clinical monitoring. Subsequently, two surgical interventions in 2021 and 2022 revealed histopathological findings indicating low-grade anal squamous intraepithelial lesions (ASIL). In January 2023, a high-resolution anoscopy (HRA) was performed as part of ongoing ASIL surveillance, identifying atypical squamous cells of undetermined significance (ASC-US). This discovery led to a re-intervention in February 2023, involving electrofulguration of suspected lesions suggestive of HPV infection. In March 2023, the patient’s treatment regimen was altered, transitioning from anti-TNF therapy to an α₄β₇ integrin antagonist due to a documented lack of response to the former. This decision was supported by significantly elevated fecal calprotectin levels (>2200 mg/g) and the presence of detectable anti-TNF antibodies. Importantly, despite this change in therapy, the patient exhibited a favorable clinical response and is currently under stringent surveillance, with continuous monitoring and assessment of ASIL. Results: The prevalence of ASIL or SCC in patients with IBD undergoing immunosuppressive drug therapy remains uncertain. Previous research has suggested that oncogenic strains of HPV are the primary infectious agents contributing to the development of ASIL. Immunocompromised individuals, such as those with HIV and solid organ transplant recipients, have been observed to have a higher incidence of ASIL. Therefore, patients diagnosed with IBD who are concurrently undergoing immunosuppressive drug therapy or have a history of chronic perianal lesions may be considered a potentially high-risk subgroup. However, it’s important to note that the CESAME cohort study failed to establish a definitive association between the use of thiopurines and the occurrence of anal cancer in patients with IBD. Notably, the crude risk within the subset of perianal Crohn’s disease patients exposed to thiopurines was calculated at 0.42 per 1000 patient-years. Additionally, findings from the TREAT and ENCORE registries did not reveal a significant increase in the incidence of anal cancer among patients treated with infliximab, providing further insights into the complex relationship between immunosuppressive therapy and the risk of anal malignancies in the context of IBD management. Conclusions: This case illustrates that timely intervention in the identification of anal lesions predisposing to cancer in patients with IBD and immunosuppressive therapy, using high-resolution anoscopy, can play a crucial role in the prevention and management of anal squamous neoplasms. Further research is needed to better understand the impact of immunosuppressive therapy on the progression of these lesions and to establish clear guidelines for detection and management in this high-risk population.