INDUCTION OF ESOPHAGEAL AND FORESTOMACH CARCINOMAS IN RATS BY REFLUX OF DUODENAL CONTENTS

A study was designed to determine whether oesophageal carcinomas can be induced through reflux of duodenal contents. Male Wistar rats weighing 230-250 g were divided into three groups according to the surgical procedure performed: (1) the duodenal contents were directed into the forestomach through a stoma (duodeno-forestomach reflux); (2) the duodenal contents were regurgitated into the forestomach through the glandular stomach (duodeno-glandular-forestomach reflux); and (3) a sham operation was performed as a control. Animals were fed standard CRF-I solid food and tap water that was not exposed to carcinogens and were sacrificed 50 weeks post-operatively. While no neoplasia was observed in any of the 32 control rats, 4/11 (36%) with duodeno-forestomach reflux and 3/18 (17%) animals with duodeno glandular-forestomach reflux developed carcinomas in the lower oesophagus and forestomach. The incidence in each group was significantly higher than in the controls (P<0.01 and P<0.05 respectively). Six of the seven lesions consisted of squamous cell carcinomas, and one was a mucinous adenocarcinoma. Oesophageal columnar epithelial metaplasia was observed in two (18%) of the animals with duodeno-forestomach reflux. Carcinomas were always surrounded by chronic inflammatory changes, including regenerative thickening, basal cell hyperplasia and dysplasia. Additional well-differentiated adenocarcinomas were observed in the prepyloric antrum of 6/18 (33%) animals with duodeno-glandular-forestomach reflux. These findings indicate that chronic reflux of duodenal contents may cause oesophageal carcinoma.