THE OCCURRENCE OF COLON-CANCER IN PATIENTS WITH KNOWN PREMALIGNANT COLONIC MUCOSAL DISEASES

Both ulcerative colitis and familial polyposis are colonic mucosal dis eases which are known to predispose to colon cancer. While colonoscopy is an accurate modality used in screening and surveillance for patien ts with these two diseases, patients continue to present with colon ca ncer with these known premalignant diseases. This study was conducted to ascertain why patients with known premalignant disease still develo p life-threatening colon cancer and to assess the clinical profile and prognosis of patients with known ulcerative colitis (UC) and familial polyposis coli (FPC) who subsequently develop colon cancer. Total col ectomy, mucosal proctectomy, and ileoanal pullthrough was performed on 367 patients with UC and FPC between January 1982 and March 1993 at o ur institution. Of these, 15 had invasive adenocarcinoma of the colon (4.1%) in addition to the primary disease. These 15 patients were stud ied in detail. The average duration of disease from diagnosis to defin itive treatment of cancer was 17 years. Thirteen of the patients in th is series had UC (87%), while only 2 had FPC (13%). Colonoscopy was us ed to make the diagnosis in 11 patients (73%), while the diagnosis was made only at the time of surgery in 3 (20%). Nine of the patients pre sented with a Dukes' B-2 cancer or worse, representing 60% of the seri es. A high percentage had synchronous invasive cancers in this series- 6 patients (40%). Despite the relatively high percentage of advanced c ancers in this series, at a mean follow-up of 47.1 months, 14 of the 1 5 patients are still living. One patient has known recurrent disease w hile 1 has an elevated CEA with no other evidence of recurrence. Our f ormal survey demonstrated that many of the patients did not participat e in a regular surveillance program. Many were also inadequately infor med as to surgical options and deferred surgery because they feared a permanent stoma. We conclude that despite the availability of colonosc opic surveillance (1) colon cancers continue to occur in patients with premalignant colonic mucosal diseases; (2) a high percentage of the c ancers are advanced and synchronous cancers; (3) the cancers occur at a much younger age and are evenly distributed throughout the colon; (4 ) many patients demonstrate poor compliance with regular follow-up, th us contributing to the difficulty with early detection; and (5) patien ts often are unaware of surgical options and fear having a permanent s toma. (C) 1991 Academic Press, Inc.