Ileal pouch-anal anastomosis in familial adenomatous polyposis and ulcerative colitis with coexisting colorectal cancer: a guideline for treatment.

Patients with familial adenomatous polyposis (FAP) or ulcerative colitis (UC) are at increased risk of colorectal cancer (CRC), making surgical decision-making complex. This case series reviews six patients with FAP or UC who developed CRC and underwent ileal pouch-anal anastomosis (IPAA). Two patients with stage III CRC developed metastases, while the remaining four with stage I/II had no recurrence. IPAA is feasible in stage I/II CRC regardless of tumor location. For stage III colon cancer, total proctocolectomy (TPC) with IPAA followed by adjuvant chemotherapy is appropriate. In stage III rectal cancer more than 2 cm from the dentate line, IPAA can follow total neoadjuvant treatment (TNT). For tumors within 2 cm of the dentate line, TPC with end ileostomy is advised. IPAA may be contraindicated in cases with severe proctitis due to bleeding risk or radiation intolerance. Overall, IPAA is a suitable option for selected FAP or UC patients with CRC.