Radiological outcomes in perianal fistulizing Crohn's disease: A systematic review and meta‐analysis

Abstract

Perianal fistulas are a common and debilitating manifestation of Crohn's disease. Since the advent of biological agents, patient outcomes appear to have improved. While rates of clinical response and remission are well characterized in literature, magnetic resonance imaging (MRI) outcomes remain less so. This is despite previous studies demonstrating the persistence of fistula tracts on MRI, in spite of clinical healing, suggesting radiological markers of improvement may be more accurate. The aims of this study were to systematically review the literature for all studies reporting on MRI outcomes following biological therapy and to compare rates of radiological healing to clinical remission. A search was performed according to the Preferred Reporting Items For Systematic Reviews and Meta‐Analysis (PRISMA) guidelines. Nine articles were included, with a total sample size of 259 patients. Of these 259 patients, 47% achieved clinical remission following induction therapy and 42% following a median of 52 weeks' maintenance therapy. Out of the 259 patients, 7% achieved radiological healing in the short term and 25% in the long term. The odds ratio of MRI versus clinical healing was 0.10 (95% confidence interval [CI], 0.02–0.39) and 0.43 (95% CI, 0.26–0.71), respectively, at those corresponding time points. MRI healing of perianal fistulizing Crohn's, while arguably a more accurate assessment of treatment response, is significantly less common than clinical remission. Heterogeneity exists in the definition of radiological and clinical response, leading to variation in reported rates. Further studies, directly comparing the long‐term outcomes of patients achieving clinical remission and MRI healing are required, to better inform the role of MRI follow up in clinical practice.

Long‐term outcomes of perianal fistulizing Crohn's disease in the biologic era

“…However, a limitation is its retrospective nature, with inconsistencies in the amount of documentation and data available. We have previously noted discrepancies in outcomes assessed with relation to pfCD among the current literature, particularly pertaining to what constitutes clinical “response.” 9 Hence, we limited the clinical outcomes assessed in our study to the stricter end‐point of clinical “remission,” which is more consistently defined as closure of all baseline draining fistulas within the current literature, to avoid introduction of potential treatment bias from clinicians. As a result, we found that only 44 of 93 (47%) of our patients had complete results of clinical assessments available for comparison.…”

“…Clinical remission was defined as closure of all baseline fistulas, occurring at any time during the period of follow‐up. Radiological healing was defined as the absence of any T2‐hyperintense sinuses, tracts, or collections, corresponding to a Van Assche score of 0, 10 in keeping with the current literature definition of MRI healing 9 …”

“…In contrast, radiologic assessment with magnetic resonance imaging (MRI) appears to be a more accurate and objective measure of disease activity, given the potential for persisting underlying fistula tracts on imaging, despite clinical healing 8,9 . However, few studies have characterized the radiological outcomes of pfCD, following biological therapy, with significant heterogeneity in patient cohorts in these studies 9 .…”

“…In contrast, radiologic assessment with magnetic resonance imaging (MRI) appears to be a more accurate and objective measure of disease activity, given the potential for persisting underlying fistula tracts on imaging, despite clinical healing 8,9 . However, few studies have characterized the radiological outcomes of pfCD, following biological therapy, with significant heterogeneity in patient cohorts in these studies 9 . Furthermore, no universally accepted grading system exists to evaluate the severity of disease radiologically, with conflicting findings regarding the clinical utility of the Van Assche score, a composite radiological score that incorporates both inflammatory and anatomical features on MRI pelvis 10 .…”

An Association of Mucinous Adenocarcinoma With Chronic Peri-Anal Fistula: A Brief Review of Pathophysiology of Rare Tumor

“…The MA accounts for 2-3% of all anorectal malignancies. In most cases, prolonged duration inflammation is the possible reason for fistula-related carcinomas [4]. Diagnosis is frequently not made on time because the disease appears very slowly with fewer symptoms.…”