The stimulating effect of acetic acid, alcohol and thermal burn injury on esophagus and forestomach carcinogenesis induced by N-nitrososarcosin ethyl ester in rats.

Five groups of outbred white male rats were given N-nitrososarcosin ethyl ester (NSEE) i.g. for 4 or 6 months at a daily dose of 50 mg/kg of body wt. 5 days/week. Some groups of animals were given a 3% water solution of acetic acid or a 40% solution of ethanol i.g. for 8 months from the beginning of the experiment. The remaining groups of these rats received controlled local thermal burn injury of the esophageal mucosa 15 days before the beginning of the experiment. Acetic acid solution increased the multiplicity of benign and malignant tumors as well as carcinoma incidence in the esophagus. Ethanol in combination with NSEE did not influence carcinogenesis in the esophagus but increased the incidence of leukokeratosis and the multiplicity of forestomach papillomas. In rats treated with NSEE after thermal burn injury, a significant increase in the frequency and multiplicity of papillomas was found in the burn zone.