eP568 - Malignancy Arising from Ileal Pouch-Anal Anastomosis in Patients with Ulcerative Colitis

Purpose/Background: Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) for Ulcerative Colitis (UC) minimizes the risk of neoplasia, but does not eliminate the possibility of cancer. Due to the low incidence of IPAA malignancies, the diagnosis and management of these cancers remains understudied. The aim of this study was to identify patients who developed malignancy within the IPAA and to detail their characteristics.Methods/Interventions: The operative database of a single institution was queried from 2018-2023. Patients who developed malignancy within the IPAA requiring pouch excision were identified. Chart review was performed to identify demographic, radiographic, surgical, and pathological characteristics.Results/Outcomes: Four patients who previously underwent TPC-IPAA for UC and later developed malignancy were identified. All four patients had a mucosectomy and hand-sewn IPAA. The first case is of a 78 year old male who developed rectal bleeding 33 years after IPAA formation and was found to have a tubulovillous adenoma of the pouch on pouchoscopy. He was referred to a tertiary care center for further care but had challenges in arranging his appointments. Six months after development of the polyp he was found to have locally advanced adenocarcinoma of the pouch. He underwent 12 cycles of chemotherapy followed by short course chemoradiation and pouch excision. He has recovered well and has had no evidence of disease for 3 months. The second case is of a 62 year old female who developed chronic pouchitis 20 years after IPAA creation. She was followed with serial pouchoscopies and was found to have dysplasia in biopsies of the chronically inflamed pouch 26 years after pouch creation. She underwent pouch excision and was found to have a T3N2 small bowel adenocarcinoma. She developed multiple lung metastases and passed away within 3 years of diagnosis. The third case is of a 52 year old male who developed adenocarcinoma of the rectal cuff and pouch perineal fistula 25 years after IPAA. He was diagnosed with a T4N1 rectal cancer. He underwent total neoadjuvant chemotherapy, chemoradiation, and pouch excision. While undergoing his neoadjuvant chemotherapy he was found to have lymphoma of his right inguinal lymph nodes. He underwent chemotherapy for this malignancy as well. He did well for 1 year and was lost to follow-up due to an insurance change. The last patient was a 69 year old male who developed moderately differentiated squamous cell carcinoma of the anal canal extending into the pouch 33 years after IPAA. He underwent chemoradiation and pouch excision. He has had no-evidence of disease for 3 months. The mean time to development of malignancy following formation of IPAA was 29 years.Conclusion/

Discussion: Four patients were identified who developed malignancy within the IPAA more than two decades following IPAA creation. Serious consideration should be made for a surveillance schedule for all patients with IPAA as malignancy can develop many years after IPAA creation.