To the Editor Dr Samadder and colleagues1 showed that among patients with familial adenomatous polyposis (FAP), the use of sulindac and erlotinib compared with placebo resulted in a lower duodenal polyp burden (calculated as the sum of the diameters of polyps within a 10-cm study segment) after 6 months. I have 2 concerns about the study.
First, as the authors used a 10-cm study segment of proximal duodenum from the pyloric channel, and the whole duodenum (ie, its 4 portions) is anatomically approximately 25 cm long, their assessment of duodenal adenomatous polyp burden was presumably limited to the first portion and the upper half of the second portion of the duodenum, down to the area of the ampulla of Vater, which was examined using a side-viewing endoscope. However, there is convincing evidence from the literature that in patients with FAP, the distribution of duodenal adenomas is predominantly distal, usually in the second and third parts of the duodenum.2- 4 Of 88 patients with FAP and duodenal polyps, none had involvement of the duodenal bulb alone, 8 patients (9%) had involvement of the bulb and the second (mainly periampullary region) and third parts of the duodenum, and 80 patients (91%) had involvement of the second and third parts of the duodenum only.2 Thus, the 10-cm proximal duodenal segment explored by the authors, while probably including the periampullary area, did not examine and may not have been representative of those more distal areas predominantly involved by adenomas in FAP, a limitation not discussed by the authors.
Claude Matuchansky. Sulindac and Erlotinib for Familial Adenomatous Polyposis. JAMA. 2016;316(5):544–545. doi:10.1001/jama.2016.7592