Outcomes of Subtotal Colectomy with Ileorectal Anastomosis and Intensive Endoscopic Surveillance in Familial Adenomatous Polyposis: A Case Series

Background: Familial adenomatous polyposis (FAP) is an inherited disorder caused by mutations in the adenomatous polyposis coli gene, causing numerous colorectal adenomas to develop. If left untreated, FAP is associated with a nearly 100% lifetime risk of colorectal cancer. Subtotal colectomy with ileorectal anastomosis (IRA) is a surgical option that preserves rectal function but necessitates intensive postoperative surveillance due to the residual risk of malignancy in the retained rectum. Methods: This small retrospective case series included seven patients with FAP who underwent subtotal colectomy with IRA at a single institution between 2015 and 2024. Postoperative management involved intensive colonoscopic surveillance and polypectomy of rectal lesions. Additionally, the exploratory use of adjunctive silymarin was recorded. Clinical and pathological data were analyzed, including the incidence of residual rectal polyps, bowel function, and clinical outcomes. Results: Over a median follow-up of 38.0 months, six of the seven patients developed residual rectal polyps during follow-up, which were successfully removed through polypectomy without evidence of malignant transformation. Bowel function was well-preserved in all patients, with rectal lengths ranging from 10 to 15 cm. Silymarin, a natural polyphenolic flavonoid with potential chemopreventive effects, was administered to six of the seven patients, among whom it was well-tolerated. The long-term effects of silymarin are under evaluation during ongoing follow-up. Conclusion: Subtotal colectomy with IRA, combined with regular colonoscopic surveillance and timely polypectomy, demonstrates short-term feasibility and may be an effective management strategy in selected patients for preserving bowel function. The exploratory use of silymarin was well-tolerated; however, its clinical efficacy remains strictly hypothesis-generating and further clinical trials are needed to validate its safety and potential role in human populations. These findings highlight the necessity of individualized surgical planning and vigilant long-term surveillance in FAP management.