[Comparison of different serological methods in screening early gastric cancer]

Objective: To compare the consistency and detection rate of early gastric cancer (EGC) of three different methods including anti-Helicobacter pylori (Hp) antibody combined with pepsinogen (PG) (ABC method), serum PG combined with gastrin-17 (G-17) (new ABC method) and the new scoring system. Methods: Serological tests were performed in Zhejiang population, which divided the subjects into low risk, intermediate risk and high risk groups. High risk subjects were examined by endoscopic and pathological examination. SPSS19.0 were used to evaluate the consistency of three methods. According to the receiver operating characteristic (ROC) curve, the ratio of G-17 to PG (PGR) was calculated for the optimal diagnostic cut-off value of EGC. Results: A total of 30 126 subjects were recruited. Based on the data of ABC method, the proportions of low risk, intermediate risk and high risk group were 15 368 (51.01%), 13 246 (43.97%), and 1 512 (5.02%), respectively. These proportions by the new ABC method were 20 584 (68.32%), 8 990 (29.84%), 552 cases (1.83%), respectively. By new scoring system, these were 20 810 (69.08%), 8 059 (26.75%), and 1 257 (4.17%), respectively. Among them, 1 263 subjects underwent endoscopy and 22 cases (1.74%) were finally diagnosed as gastric cancer including 19 EGC (86.4%). There were 1 case (0.35%), 14 cases (1.84%), and 7 cases (3.21%) with gastric cancer in low risk, intermediate risk, and high risk groups by ABC methods, respectively. Gastric cancer patients were 7 (1.68%), 10 (1.38%), and 5 (4.10%) in three groups respectively by new ABC methods. Via new scoring system, gastric cancer were detected in 5 (0.66%), 9 (2.22%), and 8 (7.84%) patients of three risk groups respectively. The consistency of three screening methods was poor. The detection rate of gastric cancer in high risk group was higher than that in the other two (P<0.05). The area under the curve (AUC) for diagnosis of gastric cancer by G-17 and PGR was 0.588 and 0.729, respectively. According to the PGR cut-off value determined by the fitted model, the incidence of gastric cancer in the low, intermediate and high risk groups was 0.94%, 1.97%, and 6.31%, respectively. When the cut-off value is PGR<4.135, the sensitivity is 0.855 and the specificity is 0.545. Conclusion: The new scoring system has a better predictive value in EGC screening. The detection rate of EGC in high risk group is higher than that in low and intermediate risk groups.