Perianal Crohn's Disease Research Articles

Temporary Faecal Diversion for Refractory Perianal and/or Distal Colonic Crohn's Disease in the Biologic Era: An Updated Systematic Review with Meta-analysis.

We evaluated short- and long-term outcomes of temporary faecal diversion [FD] for management of refractory Crohn's disease [CD], focusing on outcomes in the biologic era. Through a systematic literature review until March 15, 2023, we identified 33 studies [19 conducted in the biologic era] that evaluated 1578 patients with perianal and/or distal colonic CD who underwent temporary FD [with intent of restoring bowel continuity] and reported long-term outcomes [primary outcome: successful restoration of bowel continuity, defined as remaining ostomy-free after reconnection at a minimum of 6 months after diversion or at the end of follow-up]. We calculated pooled rates (with 95% confidence interval [CI]) using random effects meta-analysis, and examined factors associated with successful restoration of bowel continuity. Overall, 61% patients [95% CI, 52-68%; 50% in biologic era] experienced clinical improvement after FD. Stoma takedown was attempted in 34% patients [28-41%; 37% in biologic era], 6-18 months after diversion. Among patients where bowel restoration was attempted, 63% patients [54-71%] had successful restoration of bowel continuity, and 26% [20-34%] required re-diversion. Overall, 21% patients [17-27%; 24% in biologic era] who underwent FD were successfully restored; 34% patients [30-39%; 31% in biologic era] required proctectomy with permanent ostomy. On meta-regression, post-diversion biologic use and absence of proctitis was associated with successful bowel restoration after temporary FD in contemporary studies. In the biologic era, temporary FD for refractory perianal and/or distal colonic CD improves symptoms in half the patients, and bowel continuity can be successfully restored in a quarter of patients.

Nutritional status in perianal Crohn's disease: are we underestimating the impact?

Symptomatic perianal disease is common in patients with Crohn's disease (CD), and perianal fistulas represent the primary form of anal involvement. This type of involvement is associated with a poor prognosis and a disabling course. The treatment is challenging and involves both surgical and medical approaches. Despite combined therapy, a significant portion of patients may still require proctectomy to control the symptoms. Consequently, investigating factors that may influence the outcome of perianal disease remains a priority area of research in CD. Nutritional deficiencies are well documented among CD patients with luminal forms of involvement and are closely related to poor clinical outcomes, therapy response, and postoperative complications. As a result, leading guidelines recommend regular nutritional assessment and correction of nutritional deficiencies in patients requiring a surgical approach. Despite these recommendations and the high rate of surgeries among CD patients with perianal disease, there is a shortage of studies addressing the real impact of nutritional status on the course and outcomes of perianal disease. This knowledge gap underscores the importance of further research to understand better and improve the management of perianal CD. This narrative review aims to provide an overview of nutritional status assessment and the influence of nutritional status on the outcomes of patients with perianal CD.

Management of Perianal Fistulizing Crohn's Disease.

Perianal fistulizing Crohn's disease (CD) represents a severe phenotype of CD that is associated with significant morbidity and reduction in quality of life. Perianal fistulizing CD is caused by a complex interplay of genetic predisposition, immune dysregulation, gut dysbiosis, and various unknown physiological and mechanical factors. A multidisciplinary approach is hence required for optimal management . A detailed anatomical description and classification of perianal fistula, including comprehensive clinical, endoscopic, and radiological diagnostic workup, is an important prerequisite to treatment. For simple perianal fistulas, use of antibiotics and immunomodulators, with or without fistulotomy, are appropriate measures. The medical management of complex perianal fistula, on the other hand, requires adequate control of infection before initiation of therapy with immunomodulators. In active complex perianal fistula, anti-tumor necrosis factors remain the most accepted therapy, with concomitant use of antibiotics or immunomodulators enhancing the efficacy. For patients refractory to anti-tumor necrosis factors, treatment with anti-integrins, anti-interleukins, and small molecules is being evaluated. Mesenchymal stem cells, hyperbaric oxygen therapy, and exclusive enteral nutrition have also been investigated as adjunct therapies. Despite the expansion of the medical armamentarium, a large proportion of the patients require surgical interventions. In this review, we provide an up-to-date overview of the pathophysiology, clinical presentation, diagnosis, and medical management of perianal fistulizing CD. A brief overview of the surgical management of perianal fistulizing CD is also provided.

Anal squamous cell carcinoma mimicking pyoderma gangrenosum in a patient with crohn’s disease

Anal neoplasia in Inflammatory Bowel Disease is rare and has been associated with HPV and perianal disease. We report a case of a large perianal ulcer in a patient with a non perianal Crohns disease that it was initially misdiagnosed and treated as pyoderma gangrenosum.

Evaluation of the mechanical properties and clinical application of nickel-titanium shape memory alloy anal fistula clip.

The study investigates the mechanical properties of a nickel-titanium shape memory alloy anal fistula clip (NiTi-AFC), studies the surgical method of treating anal fistula, and evaluates its clinical efficacy. The anal fistula clip was formed in nickel-titanium alloy with a titanium content of 50.0%-51.8%. The mechanical properties and chemical properties were tested. A total of 31 patients with anal fistula were enrolled between 1 January 2020 and 1 January 2023. All patients underwent internal orifice closure surgery using NiTi-AFC, and anorectal magnetic resonance or ultrasound was performed before surgery and 6 months after surgery for diagnosis and evaluation. Fistula cure rates, length of stay, perianal pain, and Wexner incontinence scores were retrospectively compared between patients treated with NiTi-AFC and patients treated with other surgical methods. NiTi-AFC has a density of 6.44-6.50 g·cm-3, with a shape-restoring force of 63.8 N. The corrosion rate of NiTi-AFC in 0.05% hydrochloric acid solution at atmospheric pressure and 20°C is approximately 6.8 × 10-5 g·(m·h)-1. A total of 31 patients (male/female: 19/12, age: 43.7 ± 17.8 years) were included. Among them, 22.6% (7) had multiple anal fistula, 16.1% (5) had high anal fistula, and 48.3% (15) had perianal fistula Crohn's disease. In total, 12.9% (4/31) did not achieve primary healing, underwent fistula resection, and eventually recovered. A retrospective analysis showed that the fistula healing rate, length of stay, and anal pain of NiTi-AFC treatment were similar to those of other traditional surgeries, but the Wexner incontinence score was significantly lower. NiTi-AFC has shape memory properties, corrosion resistance, superelastic effect, and surface cell adhesion. It is applied to internal orifice closure surgery of anal fistula, with good therapeutic effect, and can protect the anal function.

Clinical and magnetic resonance imaging spectrum of complex perianal fistulizing Crohn's disease: A cohort study from northern India.

Fistulizing perianal Crohn's disease (CD) is a debilitating condition associated with significant morbidity and reduction in thequality of life. Magnetic resonance imaging (MRI) of the pelvis is the preferred imaging modality for thecomprehensive assessment of the perianal fistula. There is apaucity of data from India on the MRI spectrum of complex perianal fistula in CD. A single-centre cross-sectional analysis of patients with fistulizing perianal CD, who underwent pelvic MRI between January 2020 and December 2021, was performed. The clinical (age, sex, disease duration, disease location and behavior, disease activity [Perianal Disease Activity Index, PDAI] and treatment received) and radiological (number and location of fistulae, extensions, number and location of internal and external openings, fistula activity, presence or absence of perianal abscess and associated proctitis) characteristics of complex perianal fistula (defined according to the American Gastroenterological Association classification) were recorded. Of total 175 patients with CD who attended the gastroenterology clinic during the study period, 27 (15.42%) (mean age 42±15.5 years, 62.96% females and median disease duration four years) had complex perianal fistula and were included in the analysis. The mean PDAI was 5.48±2.53. The median Van Assche Index was 17 (interquartile range [IQR] 13-19). A majority (96.29%) of the fistulae were trans-sphincteric and four (14.81%) fistulae extended into the supralevator space. All fistulae were active on MRI. Concomitant perianal abscess and proctitis were seen in 59.26% (n=16) and 62.96% (n=17) of patients, respectively. Combination therapy with biologics and antibiotics/immune-suppressants were the most commonly prescribed medical therapy. Six (22.22%) patients underwent combined medical and surgical (non-cutting seton, fistulectomy, fecal diversion) treatment. The cumulative risk of thedevelopment of fistulizing perianal CD in a northern Indian cohort was similar to the western populations. Complex perianal fistulae were predominantly trans-sphincteric and commoner in females. MRI evaluation is pivotal forthe delineation of fistula anatomy, assessment of disease extent and activity and theevaluation of concomitant perianal abscess and other complications.

Continuing Medical Education Questions: August 2023.

Article Title: Management of Perianal Crohn's Disease.

Rates and Predictors of Long-term Clinical Outcomes in Patients With Perianal Crohn's Disease on Biologic Therapy.

Perianal Crohn's disease (pCD) represents an aggressive phenotype with limited studies on long-term outcomes. We evaluated 5-year outcomes of these patients on biologic therapies. We performed a retrospective analysis of patients with pCD at a tertiary medical center. We used Kaplan-Meier curves to estimate rates and multivariate logistic regression to identify predictors of long-term outcomes. We included 311 patients with pCD of which 168 patients were started on biologics [138 anti-tumor necrosis factor (TNF) α, 14 vedolizumab, 16 ustekinumab] at the time of diagnosis. Anti-TNF use at the time of diagnosis was associated with decreased rates of perianal abscess recurrence [hazard ratio (HR)=0.48, 95% confidence interval (CI): 0.32-0.74], whereas ustekinumab use was associated with increased rates of perianal fistula closure (HR=3.58, 95% CI: 1.04-12.35) and decreased rates of perianal abscess recurrence (HR=0.20, 95% CI: 0.07-0.56) at follow-up. Among patients who failed their first anti-TNF, switching to another anti-TNF was associated with decreased rates of colectomy (HR=0.20, 95% CI: 0.04-0.90) and permanent diversion (HR=0.16, 95% CI: 0.03-0.94) compared with ustekinumab, whereas vedolizumab use was associated with decreased perianal fistula closure (HR=0.22, 95% CI: 0.05-0.96) compared with ustekinumab. Predictors of colectomy included colonic disease (odds ratio=2.71, 95% CI: 1.36-5.38) and anal stenosis (odds ratio=4.44, 95% CI: 1.59-12.43). Type of biologic use at the time of pCD diagnosis or after first anti-TNF failure may be associated with long-term outcomes in patients with pCD.

Epidemiology, Disease Course, and Clinical Outcomes of Perianal Fistulas and Fissures Crohn's Disease: A Nationwide Population-Based Study in Taiwan.

Population-based data on the course of perianal disease in East Asian populations with Crohn's disease (CD) are limited. This study examined the prevalence, clinical course, and compared the outcomes of CD patients with perianal CD (pCD) versus without pCD in Taiwan. A nationwide population-based study was implemented from 2000 to 2017 by using the Taiwan National Health Insurance Research Database. Of 2424 patients with CD, 358 (14.8%) patients with pCD were identified. Most patients with CD and pCD were men (79.3%). The mean age at CD diagnosis was lower in patients with pCD (33.7 years) than in those without pCD (44.9 years). Approximately half the patients with pCD received the pCD diagnosis at least 6 months before receiving a CD diagnosis. Approximately one-third (121/358) of patients with pCD had recurrent fistula; the median recurrence interval was 239 days. Compared with patients without pCD, patients with pCD had higher mean incidences of hospitalization (7.0 vs 3.8, P < .01), outpatient visits (13 vs 2.9, P < .01), and emergency room visits (10.3 vs 4.4, P < .01) over a 15-year period. Although patients with pCD had higher rates of healthcare utilization, their 15-year mortality rate was lower than that of those without pCD (6.1% vs 17.3%, P < .01). The period prevalence of pCD in Taiwanese patients with CD was 14.8%. Although patients with pCD required more intensive care and had greater healthcare utilization, they did not have inferior survival outcomes compared with those without pCD.

Surgical approaches to perianal Crohn's disease

Virtually one-third of patients with Crohn’s disease (CD) develop anal symptoms. In addition to the typical skin tags and chronic fissures, 50% of these patients develop perianal abscesses and fistulas, which are among the most challenging CD phenotypes to treat. They can significantly affect patients’ quality of life (QOL) and result in a significant amount of lost days at school or work, as they often occur in a young, active population.

Management of Perianal Crohn's Disease - AJG.

Perianal Crohn's disease affects 25-35% of Crohn's disease patients and has proven to be one of the most difficult complications of the disease to treat. Patients with perianal Crohn's disease have lower health related quality of life scores typically related to pain and fecal incontinence. Additionally, perianal Crohn's patients have higher rates of hospitalizations, surgeries and overall healthcare costs. A multidisciplinary approach is necessary for the successful management of Crohn's disease with perianal fistula. Medical management is required to treat the underlying immune dysregulation to heal the luminal inflammation as well as the inflammation within the fistula tracts. Current options for medical therapy include biologics, dual therapy with thiopurines, therapeutic drug monitoring and close follow-up. Surgical management is critical to drain abscesses prior to immunosuppressive therapy and place setons when appropriate. Once the patient's inflammatory burden is well managed, definitive surgical therapies including fistulotomies, advancement flaps and ligation of intersphincteric fistula tract procedures can be considered. Most recently, the use of stem cell therapy in the treatment of perianal fistula has given new hope to the cure of perianal fistula in Crohn's disease. This review will outline the most current data in the medical and surgical management of perianal Crohn's disease.

Early Ileocecal Resection for Crohn’s Disease Is Associated With Improved Long-term Outcomes Compared With Anti-Tumor Necrosis Factor Therapy: A Population-Based Cohort Study

Early Crohn's disease (CD) treatment involves anti-tumor necrosis factor (TNF) agents, whereas ileocecal resection (ICR) is reserved for complicated CD or treatment failure. We compared long-term outcomes of primary ICR and anti-TNF therapy for ileocecal CD. Using cross-linked nationwide registers, we identified all individuals diagnosed with ileal or ileocecal CD between 2003 and 2018 and treated with ICR or anti-TNF agents within 1 year of diagnosis. The primary outcome was a composite of ≥1 of the following: CD-related hospitalization, systemic corticosteroid exposure, CD-related surgery, and perianal CD. We conducted adjusted Cox's proportional hazards regression analyses and determined the cumulative risk of different treatments after primary ICR or anti-TNF therapy. Of 16,443 individuals diagnosed with CD, 1279 individuals fulfilled the inclusion criteria. Of these, 45.4% underwent ICR and 54.6% received anti-TNF. The composite outcome occurred in 273 individuals (incidence rate, 110/1000 person-years) in the ICR group and in 318 individuals (incidence rate, 202/1000 person-years) in the anti-TNF group. The risk of the composite outcome was 33% lower with ICR compared with anti-TNF (adjusted hazard ratio, 0.67; 95% confidence interval, 0.54-0.83). ICR was associated with reduced risk of systemic corticosteroid exposure and CD-related surgery, but not other secondary outcomes. The proportion of individuals on immunomodulator, anti-TNF, who underwent subsequent resection, or were on no therapy 5 years post-ICR was 46.3%, 16.8%, 1.8%, and 49.7%, respectively. These data suggest that ICR may have a role as first-line therapy in CD management and challenge the current paradigm of reserving surgery for complicated CD refractory or intolerant to medications. Yet, given inherent biases associated with observational data, our findings should be interpreted and applied cautiously in clinical decision making.

Internal Orifice Alloy Closure: A New Procedure for Treatment of Perianal Fistulizing Crohn's Disease.

BACKGROUND The high recurrence rate of perianal fistula Crohn's disease (PFCD) increases the need to protect the anal sphincter during each surgical treatment of fistulas. We aimed to evaluate the safety and efficacy of internal orifice alloy closure in patients with PFCD. MATERIAL AND METHODS Fifteen patients with PFCD were enrolled in the study between July 6, 2021, and April 27, 2023. All patients underwent preoperative colonoscopy and anal magnetic resonance examination for diagnosis and evaluation. Internal orifice alloy closure (IOAC) was performed only when Crohn's disease was in remission. The external sphincter had not been severed. Perianal magnetic resonance imaging examination was used for postoperative evaluation after 6 months. Fistula cure rate, length of stay, perianal pain, and Wexner incontinence score were retrospectively compared between 15 patients treated with IOAC and 40 patients treated with other surgical methods. RESULTS Fifteen patients (male/female: 9/6, age: 23.6±14.3 years) with PFCD were included (follow-up: 24 months). In total, 20.0% (3) had multiple tracts, and 13.3% (2) had a high anal fistula. Among them, 10 patients received biologics for induction for mucosal healing before surgery. The fistula healed completely in 80.0% (12/15) and did not heal in 20.0% (3/15). Three patients who did not heal underwent fistulotomy and eventually recovered. IOAC is not superior in terms of fistula healing rates, length of stay, and anal pain, but its Wexner incontinence scores are significantly lower than with other surgical methods. CONCLUSIONS IOAC is a novel sphincter-saving surgery that is effective and safe for the treatment of PFCD.

Natural History of Anal Ulcerations in Pediatric-Onset Crohn's Disease: Long-Term Follow-Up of a Population-Based Study.

Anal ulcerations are frequently observed in Crohn's disease (CD). However, their natural history remains poorly known, especially in pediatric-onset CD. All patients with a diagnosis of CD before the age of 17 years between 1988 and 2011 within the population-based registry EPIMAD were followed retrospectively until 2013. At diagnosis and during follow-up, the clinical and therapeutic features of perianal disease were recorded. An adjusted time-dependent Cox model was used to evaluate the risk of evolution of anal ulcerations toward suppurative lesions. Among the 1,005 included patients (females, 450 [44.8%]; median age at diagnosis 14.4 years [interquartile range 12.0-16.1]), 257 (25.6%) had an anal ulceration at diagnosis. Cumulative incidence of anal ulceration at 5 and 10 years from diagnosis was 38.4% (95% confidence interval [CI] 35.2-41.4) and 44.0% (95% CI 40.5-47.2), respectively. In multivariable analysis, the presence of extraintestinal manifestations (hazard ratio [HR] 1.46, 95% CI 1.19-1.80, P = 0.0003) and upper digestive location (HR 1.51, 95% CI 1.23-1.86, P < 0.0001) at diagnosis were associated with the occurrence of anal ulceration. Conversely, ileal location (L1) was associated with a lower risk of anal ulceration (L2 vs L1 HR 1.51, 95% CI 1.11-2.06, P = 0.0087; L3 vs L1 HR 1.42, 95% CI 1.08-1.85, P = 0.0116). The risk of fistulizing perianal CD (pCD) was doubled in patients with a history of anal ulceration (HR 2.00, 95% CI 1.45-2.74, P < 0.0001). Among the 352 patients with at least 1 episode of anal ulceration without history of fistulizing pCD, 82 (23.3%) developed fistulizing pCD after a median follow-up of 5.7 years (interquartile range 2.8-10.6). In these patients with anal ulceration, the diagnostic period (pre vs biologic era), exposure to immunosuppressants, and/or anti-tumor necrosis factor did not influence the risk of secondary anoperineal suppuration. Anal ulceration is frequent in pediatric-onset CD, with nearly half of patients presenting with at least 1 episode after 10 years of evolution. Fistulizing pCD is twice as frequent in patients with present or past anal ulceration.

State-of-the-art surgery for Crohn’s disease: part III-perianal Crohn’s disease

Diagnosis and treatment of perianal Crohn's disease is challenging and requires its own domain of therapy. Different types of perianal disease require a spectrum of treatment strategies. Treatment options range from conservative therapy, including immunosuppressives, biologics, or stem cell therapy, to surgical treatment with specific indications depending on the underlying lesion. This is part III of the series "state-of-the-art surgery for Crohn's disease," focusing on the management of perianal disease. We discuss the definition and diagnosis of perianal Crohn's disease, the treatment of perianal lesions, and specific surgical indications and techniques. Pitfalls and complications play a substantial role in the treatment of perianal Crohn's disease, and surgical therapy may fail. Realistic treatment goals and an individual patient-oriented treatment approach are crucial in the treatment of perianal Crohn's disease.

Three-dimensional modelling as a novel interactive tool for preoperative planning for complex perianal fistulas in Crohn's disease.

The aim of this study is to demonstrate the added value of three-dimensional (3D) reconstruction models and artificial intelligence for preoperative planning in complex perianal Crohn's disease. MRI is the gold standard for diagnosis of complex perianal fistulas and abscess due to its high sensitivity, but it lacks high specificity values. This creates the need for better diagnostic models such as 3D image processing and reconstruction (3D-IPR) with artificial intelligence (AI) algorithms. This is a prospective study evaluating the utility of 3D reconstruction models from MRI in four patients with perineal Crohn's disease (pCD). Four pCD patients had 3D reconstruction models made from pelvic MRI. This provided a more visual representation of perianal disease and made possible location of the internal fistula orifice, seton placement in fistula tracts and abscess drainage. Three-dimensional reconstruction in CD-associated complex perianal fistulas can facilitate disease interpretation, anatomy and surgical strategy, potentially improving preoperative planning as well as intraoperative assistance. This could probably result in better surgical outcomes to control perianal sepsis and reduce the number of surgical procedures required in these patients.

Ustekinumab to treat Crohn’s colitis complicated by colonic stricture

A 28 year old male was diagnosed with moderate severe colonic and perianal Crohns disease and commenced on combination therapy with adalimumab and azathioprine

A212 THE IMPACT OF COMBINED MEDICAL AND SURGICAL TREATMENT FOR PERIANAL CROHN’S DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract Background Multidisciplinary care involving surgical drainage via examinations under anesthesia (EUA) and anti-tumor necrosis factor (TNF) therapy is recommended for perianal Crohn’s disease (PCD). However, the impact of this combined modality approach is not well-established. Purpose To determine the impact of combined modality (surgical and anti-TNF) vs. single modality (either surgical or anti-TNF) therapy on fistula healing in perianal Crohn’s disease. Method MEDLINE, EMBASE, and Cochrane databases were searched systematically from inception through September 15, 2022 independently in duplicate. We included studies that reported on fistula outcomes after treatment with combined modality vs. single modality therapy for PCD. Surgery was defined as EUA ± seton or closure procedure. Weighted summary estimates with 95% CI were estimated by random effects models. Study quality was determined using an adapted version of the Newcastle-Ottawa scale. Result(s) Thirteen studies met inclusion criteria. The total population included 1279 patients: 685 patients treated with single modality therapy with either surgical or anti-TNF therapy and 594 patients treated with combined modality therapy. Patients treated with combined modality therapy were more likely to achieve fistula healing compared to single modality therapy (65.4% vs. 57.7%; OR 1.68; 95% CI 1.03-2.73, p = 0.04) (Figure 1a). In a subgroup analysis, the rates of fistula healing were higher with combined modality therapy than with surgical therapy alone (OR 2.34; 95% CI 0.85-6.46, p = 0.10) but not anti-TNF therapy alone (OR 1.19; 95% CI 0.78-1.81, p = 0.43), although neither comparison was statistically significant (Figures 1b and c). The majority of studies were rated low-quality due to risk of bias from uncontrolled confounding variables. Image Conclusion(s) Limited high-quality evidence suggests that fistula healing occurs more frequently in patients treated with combined modality therapy. However, the benefit of a combined modality approach appears to be driven mainly by anti-TNF therapy. Further prospective randomized trials are needed to confirm these findings. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

The Use of Endoscopic Ultrasonography in Inflammatory Bowel Disease: A Review of the Literature.

The diagnosis of inflammatory bowel disease (IBD) can sometimes be challenging. By corroborating clinical, imaging and histological data, the two main entities of IBD, ulcerative colitis and Crohn's disease (CD), can be differentiated in most cases. However, there remains 10-20% of patients where the diagnosis cannot be accurately established, in which case the term "IBD unclassified" is used. The imaging techniques most used to evaluate patients with IBD include colonoscopy, ultrasonography and magnetic resonance imaging. Endoscopic ultrasonography is mainly recommended for the evaluation of perianal CD. Through this work, we aim to identify other uses of this method in the case of patients with IBD.

P119 Perianal Crohn’s disease and the development of colorectal and anal cancer: A systematic review and meta-analysis

Abstract Background Over the course of their disease, 15-30% of patients with Crohn's disease(CD) develop Perianal Crohn's disease (pCD). In approximately 5% of patients, perianal fistula is the only manifestation of their CD. Previous studies have found that perianal involvement results in an 11-fold increased risk for anal cancer. The aim of this systematic review was to assess the literature on the incidence and risk factors for colorectal cancer and anal cancer in patients with perianal Crohn’s disease. Methods A systematic review of the literature was performed using PubMed, Embase and Google Scholar. A meta-analysis was then conducted using a random-effect model. Results Five studies were included in the systematic review. Of the total patients, 26.5% had perianal Crohn’s disease. The median follow-up was 6 years. In total, 127 cases of colorectal cancer were found [0.43% of the included Crohn’s disease patients]. Perianal involvement was present in 50% of colorectal cancer patients [0.89% of the population]. Three of the studies specified the cancer to be rectal or anal, which were present in 68 and 24 cases [0.3% and 0.1% of patients], respectively. In a subgroup analysis of rectal and anal cancer, perianal involvement was most frequent in anal cancer, accounting for 46% of the cases. In the rectal cancer group, 37% had perianal involvement. The higher incidence of colorectal cancer in patients with perianal Crohn’s disease was confirmed in a meta-analysis. Conclusion Half of the patients with colorectal cancer and anal cancer were found to have perianal Crohn’s disease. In patients with perianal involvement, there was a higher percentage of anal cancer compared with rectal cancer. These results support the theory that patients with perianal Crohn’s disease are at increased risk for developing colorectal and anal cancer. Studies collecting more detailed data regarding patients and their cancers are needed to further specify the disease course.