Effects of Esophageal Constriction on Benzo[alpyrene Carcinogenesis in Hamster Esophagus and Forestomach

Summary

To constrict the lumen of the hamster esophagus, polyethylene cuffs were surgically implanted around the esophagus just above its junction with the forestomach. This procedure resulted in atrophy of epithelium at the level of the cuff and proximal dilatation of the esophagus with hypertrophy of muscle. The benzo[a]pyrene (BP) in dimethyl sulfoxide (DMSO) vehicle was instilled twice weekly for 5 weeks in the esophagus of hamsters with and without the constricting cuffs, and eventually papille;matous lesions and atypias developed in the esophagus and papillomas in the forestomach of some of the hamsters that survived to ages over 9 months. Though lesions developed in the esophagus and forestomach in hamsters in both groups treated with BP, there were differences in the types of lesions and in survival times. In the esophagus, a papillary carcinoma, papillomatosis, and an area of cellular atypia developed in 3 of 8 hamsters with constricted esophagus; a papilloma and 5 instances of cell atypia developed in 6 of 18 hamsters with non constricted esophagus. The ages of hamsters with esophageal lesions in the constricted group averaged 4.5 months less than in the nonconstricted group. In the forestomach, there were fewer papillomas per affected hamster in the constricted group, even though these hamsters were 4 months older than those with gastric papillomas in the nonconstricted group. Gastric papillomas that had progressed to carcinoma were found only in hamsters without constriction of the esophagus.