Background: The carcinogenic effect of duodenoesophageal reflux, gastroesophageal reflux, and nitrosamines was studied in the rat esophagus.
Methods: Twenty male Sprague-Dawley rats underwent esophagogastroplasty to produce gastroesophageal reflux and 60 underwent duodenoesophageal anastomosis to produce duodenoesophageal reflux. Forty-three animals underwent no operation and acted as controls. Carcinogens known to produce squamous tumors in the rat esophagus (2,6-dimethylnitrosomorpholine [DMNM] or methyl-n-amylnitrosamine [MNAN]) were tested in each group.
Results: The rate of squamous carcinoma was 25% for rats with DMNM alone, 30% for rats with MNAN alone, and 20% for rats with induced gastroesophageal reflux plus DMNM. The rate of malignant change rose to 80% in rats with induced duodenoesophageal reflux and DMNM and 67% with duodenoesophageal reflux and MNAN. With duodenoesophageal reflux, 50% of tumors were adenocarcinoma, in contrast to 100% squamous differentiation of tumors in rats given the carcinogens with esophagogastroplasty or no operation.
Conclusion: The presence of duodenoesophageal reflux increased the frequency and changed the histologic type of esophageal cancer in nitrosamine-treated rats. This indicates that duodenoesophageal reflux plays a role in the development of esophageal adenocarcinoma.