Is there a dysplasia-carcinoma sequence in rat gastric remnant?

Epithelial dysplasia in the gastric remnant is generally considered to have a positive predictive value for malignancy. Whether dysplasia progresses to carcinoma or whether both just have a common origin, is still a matter of controversy. The aim of the present study in rats was to investigate the natural history of epithelial lesions in the gastric remnant. A gastric resection was carried out in 50 male Wistar rats. Postoperatively the animals received N-methyl-N'-nitro-N-nitrosoguanidine orally. Gastroscopy was carried out monthly and biopsies were taken for histologic evaluation. The rats were killed after 12 months or if gastric cancer was found on gastroscopy. Twenty-four rats died postoperatively and were excluded from the study. A total of 228 gastroscopies was performed in the remaining 26 animals; 24 animals developed dysplastic lesions during the follow-up period. The rate of development of gastric cancer within one month increased with the stage of dysplasia at the previous examination (3% for mild, 48% for moderate, 100% for severe dysplasia). There was a strong correlation between the time period following gastric resection and grade of dysplasia and between the grade of dysplasia and development of cancer. Our study demonstrates that gastric stump cancer in rats develops from dysplastic lesions. A dysplasia-carcinoma sequence can therefore be assumed.