LAUSR

Background Sporadic nonampullary duodenal adenocarcinoma is a rare malignant neoplasm in which poor prognosis is often associated with delayed diagnosis. Objective A case-control study was designed to evaluate the clinical and endoscopic characteristics of patients with nonampullary duodenal epithelial tumours (NADETs). Methods Patients with NADETs were chronologically divided into a discovery and a validation sets. Two age- and sex-matched control individuals for each case in the discovery set were randomly selected from individuals without NADET. A prediction model for the presence of NADET, constructed in the discovery set, was evaluated in the validation set. Results In total, 368 adenomas, 81 adenocarcinomas, and 314 controls were analysed. Current smoking, Barrett oesophagus, fundic gland polyps, history of malignant disease, and absence of dyslipidaemia were independently associated with the presence of NADET. The combination of these five factors enabled significant discrimination for NADET in the bulb with a sensitivity of 0.81 in the validation set. We also showed that duodenal adenocarcinomas in the bulb had greater invasive potential than adenocarcinomas in the second portion. Conclusion The presence of a duodenal tumour in the bulb could be predicted by clinical and endoscopic findings, which helps improve the prognosis and quality of life of patients.