DOP04 Screening and management of fistula cancers in patients with perianal fistulising Crohn’s Disease: an expert consensus
Authors: Wong S Y , Rowan C , Law C C , Brockmans E D , Khaitov S , Sachar D , Altinmakas E , Ballard D , Behrenbruch C , Bislenghi G , Bonifacio C , Carvello M , Cohen B , Deepak P , Dige A , Geldof J , Hanna L , Harmath C , Holubar S , Lundby L , Lightner A , Lung P , McDonald B , McGovern D , Rubin D , Sebastian S , Spinelli A , Verstockt B , Winata L S H , Tozer P , Hart A , Colombel J F 
Published: January 2024

Abstract

Background
Fistula cancer is a rare and often devastating diagnosis in patients with perianal fistulising Crohn’s disease (CD). Fistula cancer management is a complex process requiring multi-disciplinary effort. However, given the low incidence and subsequent lack of data and clinical trials in the field, there is little to no guidance on screening and management of fistula cancer. To inform clinical practice, we developed consensus guidelines on fistula cancer in perianal fistulising Crohn’s disease by multidisciplinary experts from the international TOpCLASS consortium.

Methods
We performed a systematic review of the literature by standard methodology, using the Newcastle-Ottawa quality assessment tool. Data were retrieved from articles according to these domains: epidemiology and risk factors, clinical presentation, diagnostics, staging, and treatment. We developed consensus statements using a Delphi consensus approach. Participants included gastroenterologists, surgeons, radiologists, and pathologists. We performed two rounds of voting: (1) online survey followed by statement edits and (2) hybrid meeting with discussion until over 80% consensus was achieved for each statement.

Results
Of 550 articles identified, 99 were eligible, and 80 articles were included. The overall quality of evidence was low. Seven statements were accepted in the final consensus (Table 1).
Patients with longstanding (&gt;10 years) perianal fistulising CD should be considered at small but increased risk of developing fistula cancer, including anal squamous cell cancer (SCC) and anorectal carcinoma. Risk factors for anal SCC, including human papilloma virus (HPV), should be considered. Clinical signs and symptoms of fistula cancers are non-specific, and several case reports included asymptomatic patients. New or refractory/progressive perianal symptoms should prompt evaluation for fistula cancer. There was no consensus on timing or frequency of screening in patients with asymptomatic perianal fistula. Regarding diagnostics, multiple modalities may be required, including repeated exam under anesthesia with biopsy. Multidisciplinary team efforts were deemed central for the management of fistula cancers.

Conclusion
Clinicians managing patients with perianal fistulising CD should be aware of the risk of fistula cancers, including anal SCC and anorectal carcinoma. Our expert consensus recommends consideration of patient factors including duration of fistulas, HPV status, and perianal symptoms, and gives guidance on diagnostic modalities and treatment considerations. Multidisciplinary coordination of care is paramount, and more studies in the field are needed.