A low 13C-urea breath test value is associated with increased risk of gastric cancer.

The 13C-urea breath test (UBT) is considered to be the most accurate way of diagnosing Helicobacter pylori infection. Values are affected by H. pylori infection and by the severity of atrophic gastritis. Our objective was to determine the association of UBT values with gastric cancer, and to evaluate the risk of gastric cancer in terms of UBT values. Methods. Our study involved 413 consecutive patients who had undergone esophagogastroduodenal examination and the UBT test. Results. Of the 398 patients with positive UBT results, atrophy and intestinal metaplasia scores in both antrum and corpus were significantly higher in patients with gastric cancer than in those with gastritis, duodenal ulcer, and gastric ulcer. The UBT value related to gastric cancer (22.01 ± 1.89‰) was significantly lower than that for gastritis (35.19 ± 1.53‰; P < 0.01), duodenal ulcer (29.01 ± 1.97‰; P < 0.05), or gastric ulcer (30.79 ± 2.83‰; P < 0.05). When the UBT values were less than 20‰, increases in the risk of gastric cancer correlated with decreasing UBT values. Conclusions. These findings indicate that the UBT value related to gastric cancer is significantly lower than that for gastritis, duodenal ulcer, or gastric ulcer in H. pylori-positive patients. Low UBT values were associated with the risk of gastric cancer.