Colorectal cancer in familial adenomatous polyposis.

PURPOSE: This study was performed to determine the relationship among surgical treatment, colorectal cancer, and outcome in patients with familial adenomatous polyposis (FAP).

METHODS: Records of 115 patients with FAP who underwent surgery at The Mount Sinai Medical Center between 1947 and 1994 were retrospectively reviewed. Patients without cancer were compared with those with colorectal cancer at initial surgery and with patients who developed rectal cancer following colectomy.

RESULTS: Thirty-one patients (27 percent) had colorectal cancer at the time of initial surgery (colon = 24; rectal = 7). Another 11 patients (26 percent) developed rectal cancer after colectomy with ileorectal anastomosis (IRA). Mean age of patients with colorectal cancer at initial surgery was significantly higher than those without cancer (P < 0.01). Patients who developed rectal cancer after IRA were significantly older than patients with colorectal cancer at initial surgery (P < 0.01). All patients with rectal cancer after IRA had advanced disease with either nodal or distant metastases at the time of diagnosis.

CONCLUSIONS: Colorectal cancer remains a major problem in the treatment of patients with FAP. Nearly one-fourth of these patients have colorectal cancer at initial operation, and one-fourth of patients with IRA develop rectal cancer after a mean follow-up of 13 years. Patients with rectal cancer following IRA are more likely to have advanced tumors than patients with colorectal cancer at initial operation. The high incidence and late stage of rectal cancer detected while under surveillance after IRA supports excision of the entire colorectal mucosa as the treatment of choice for most patients with FAP.