[Value of screening of familial adenomatous polyposis for the prevention of colorectal cancer].

Familial adenomatous polyposis coli is a hereditary autosomal dominant disease which spontaneously and inevitably leads to degeneration of colorectal adenomas and requires preventive surgical treatment. The aim of this study was to evaluate the age of colorectal degeneration and the need for a screening technique in family members. Between 1983 and 1989, 141 patients were treated for familial adenomatous polyposis in our surgical center. Mean age at surgery was 32 years and 64 patients (45.4 percent) had a colorectal carcinoma. Thirty had an in situ tumor (mean age: 30 years) and 34 had an invasive adenocarcinoma (mean age: 45 years), 7 of whom died of their cancer. No colonic cancer was found in patients younger than 20. Thirty-eight percent of the patients under 40 years of age, 73 percent of the patients older than 40 years and 81 percent of those older than 50 had an adenocarcinoma. Fifty percent of the patients with carcinoma were younger than 40 years and 7 percent were less than 25 years old. Seventy-one patients were symptomatic at the time of operation (mean age: 40 years), 32 (45 percent) had a colonic cancer. In 70 patients, familial adenomatous polyposis was detected by screening (mean age: 24) and 2.8 percent had a colonic carcinoma. We conclude that the age-related risk of developing colonic carcinoma requires prophylactic surgery in asymptomatic patients before 20 years of age, and that routine familial screening would be of some benefit.