Long-term outcome of metachronous rectal cancer following ileorectal anastomosis for familial adenomatous polyposis.

BACKGROUND

Total colectomy with ileorectal anastomosis (IRA) for familial adenomatous polyposis (FAP) carries a potential risk of metachronous cancer in the residual rectum. This study evaluated the risk of cancer development in the residual rectum.

METHODS

Ninety-six patients who underwent initial surgery for prevention and cure of FAP were studied, and a clinicopathologic comparison was conducted between 59 patients who underwent IRA and 24 who underwent total proctocolectomy.

RESULTS

The 5-year overall survival rates were 94% after IRA and 95% after total proctocolectomy with no significant difference. The incidence of dense-type rectal polyps (4/17, 24%) was significantly higher in patients who developed metachronous rectal cancer following IRA compared to that in patients who did not (1/39, 3%). Moreover, 60% of patients with dense-type colon polyps developed metachronous rectal cancer compared to 24% in patients without and 80% of those with dense type rectal polyps developed metachronous rectal cancer compared to 25% without. Endoscopic surveillance of the eight Tis or T1 patients was performed at intervals of 6 months to 1 year after IRA but was not performed in three T3 patients for more than 2 years.

CONCLUSIONS

Effective IRA requires selection of patients without invasive rectal cancer and without dense rectal polyps in whom long-term postoperative follow-up of the residual rectum is possible.