Differences in and CagA antibody changes after eradication between subjects developing and not developing gastric cancer.

We evaluated serological and cytotoxin-associated gene A (CagA) antibodies and endoscopic atrophy after eradication to identify factors predicting post-eradication gastric cancer development. Thirty-five patients with successful eradiation were divided into the post-eradication gastric cancer (13 cases) and non-gastric cancer (22 cases) groups. Serum and CagA antibody titers and endoscopic atrophy before and six years after eradication were examined. Median antibody titers had decreased significantly from baseline at 0.5-2 years after eradication in both groups (gastric cancer group, from 39.0 to 11.0 U/ml,  = 0.011; non-gastric cancer group, from 29.6 to 4.97 U/ml, <0.001), but were significantly higher in the gastric cancer than in the non-gastric cancer group ( = 0.029). Median serum CagA antibody titers had also decreased significantly at 0.5-2 years after eradication (gastric cancer group, from 6.35 to 3.23 U/ml,  = 0.028; non-gastric cancer group, from 9.88 to 1.21 U/ml,  = 0.0045). Serum CagA in each group showed no significance. Endoscopic atrophy improved significantly after eradication in the non-gastric cancer, but not the gastric cancer, group ( = 0.0007). In conclusion, changes in and CagA antibody titers and endoscopic atrophy after eradication might be useful as predictive factors for post-eradication gastric cancer.