Detection of rectal neuroendocrine tumor during screening colonoscopy and its difference from colonic adenocarcinoma

摘要

Backgrounds: The incidence of rectal neuroendocrine tumors (NETs) diagnosed during screening colonoscopy is rising. The features and outcomes of these patients and their difference from colonic adenocarcinoma are unknown. Methods: Data on subjects who underwent screening colonoscopy as part of a health checkup during a five-year period were retrospectively analyzed. The prevalence and outcomes of the patients with rectal NETs were evaluated. The features of the patients with histopathologically proven NET and colonic adenocarcinoma were compared. Results: A total of 8,278 subjects were enrolled. Rectal NETs were detected and diagnosed by histopathologic analysis in 13 patients (0.16%). The mean tumor size was 0.4 ± 0.25 cm and 7.7% of the patients had chronic diarrhea. Colonic adenocarcinoma was diagnosed in 24 patients (0.29%). Patients with rectal NETs were significantly younger than those with colonic adenocarcinoma (mean age: 49.4 ± 14.2 years versus 59.5 ±11.5 years, p = 0.033) and had fewer symptoms (92.3% versus 41.7%, p = 0.001). All of the rectal NETs were successfully resected endoscopically by snare polypectomy or ligation-assisted endoscopic mucosal resection. Histopathological analysis revealed WHO 2010 grade I NETs in all patients. No recurrence was detected during a mean follow-up of 33 ± 15.2 months. Conclusions: Rectal NETs are not uncommon incidental findings of the colonic malignancies during screening colonoscopy. Those were younger and more asymptomatic as compared with colonic adenocarcinoma. Using endoscopic resection can successfully remove these small tumors without recurrence.