Intragastric N-nitrosation is unlikely to be responsible for gastric carcinoma developing after operations for duodenal ulcer.

Three groups of patients studied after operations which had cured their duodenal ulcer were compared with a control group (no operation, n = 8). The surgical procedures included: proximal gastric vagotomy (n = 7), truncal vagotomy and pyloroplasty (n = 7), truncal vagotomy and antrectomy (n = 8). Samples of gastric juice were aspirated half hourly or hourly over 24 hours for measurement of pH, counts of all identified bacteria, nitrite and total N-nitrosocompounds. Although the pH over 24 hours was significantly higher after proximal gastric vagotomy (p less than 0.05) and truncal vagotomy and antrectomy (p less than 0.001) than controls, there was no difference between truncal vagotomy and pyloroplasty and controls. Counts of nitrate reducing bacteria over 24 hours were also significantly higher after truncal vagotomy and antrectomy than controls (p less than 0.1) but no differences were observed between the other groups. Only after truncal vagotomy and antrectomy was nitrite over 24 hours significantly increased compared with controls (p less than 0.01). Despite these higher values after truncal vagotomy and antrectomy, there was no significant difference in total N-nitrosocompounds between any of the four groups. Whereas bacterial counts and nitrite increased with pH, no correlation was found between total N-nitrosocompounds and pH. These results provide no evidence that exposure to total N-nitrosocompounds is increased after operations for duodenal ulcer.