Bülow et al published results of a prospective multicentre study on analysis of the natural history of duodenal adenomas in familial adenomatous polyposis (FAP) (Gut 2004;53:381–6).

A total of 368 patients were examined over a mean period of 7.6 years (range 0.5–10.4). They showed significant progression of Spigelman stage over time (p<0.0001). At the end of the study, the incidence of Spigelman stage IV was 7.0%. These results are lower than those reported in a similar study published very recently (35% incidence of Spigelman stage IV).¹ The available literature on this issue is inconsistent. Our own experience is somewhat different. In 30 FAP patients who entered into a study of biological markers some years ago,² the development of the most severe Spigelman stage was negligible after 7–18 years of surveillance (only one case, from stage II to stage III). We found no cases with stage IV or cancer. This could be due to differences in the selection of patients. For example, in the studies of both Bülow and colleagues and Saurin and colleagues¹, data on colorectal surgery were not reported. Proctocolectomy affects bile acid metabolism and circulation.³ Bile acids are involved in the development of duodenal neoplasia.⁴

All of the patients we have under surveillance have undergone a proctocolectomy with J-pouch ileoanal anastomosis. They probably have impairment of the bile acid pool thus leading to a smaller risk of duodenal neoplasia. In Bülow’s group, a separate analysis on patients who were operated on and those who were not may be more informative in this regard.