Long-term prognosis of familial adenomatous polyposis with or without mucosectomy

Purpose This study primarily aimed to compare the long-term prognosis of patients who underwent total colectomy/proctocolectomy with or without mucosectomy to the dentate line for the diagnosis of familial adenomatous polyposis (FAP). Methods Patients who underwent total colectomy/proctocolectomy for FAP between January 1979 and December 2020 and were followed up at Hamamatsu University Hospital were included in this study. Those who underwent total proctocolectomy with hand-sewn ileal pouch–anal anastomosis were defined as the mucosectomy group. Those who underwent total colectomy or total proctocolectomy using the stapled ileal pouch–anal anastomosis approach were defined as the no mucosectomy group. Results A total of 61 individuals (37 families) were diagnosed during the surveillance period (median, 191 months). Between the mucosectomy ( n = 24) and no mucosectomy groups ( n = 34), metachronous rectal cancer was significantly more common in the no mucosectomy group (21% in no mucosectomy vs. 0% in mucosectomy, P = 0.02). Overall survival in the no mucosectomy group was worse than that in the mucosectomy group (84.5% in no mucosectomy vs. 100% in mucosectomy at 120 months, 81.1% vs. 90.0% at 240 months, 50.6% vs. 75.0% at 360 months, P = 0.09). Cox regression analysis revealed an independent effect of not performing mucosectomy on overall survival ( P = 0.03). Conclusion Long-term surveillance revealed that colectomy or total proctocolectomy without mucosectomy had a negative impact on the overall survival of patients with FAP. Therefore, we recommend total proctocolectomy with mucosectomy, i.e., hand-sewn ileal pouch–anal anastomosis, for FAP.