Abstract: Background and purpose: The opportunistic screening, also known as individual screening, is a clinic-based screening method, which is a feasible way to improve the detection rate of early gastric cancer in China. Based on the data of patients and hematological indexes, we constructed a scoring model of high risk factors for gastric cancer, and explored its value in screening gastric cancer patients. Methods: Three hundred and eighty-seven patients were enrolled in this study. We investigated the Helicobacter pylori (HP) infection, serum pepsinogen (PG)Ⅰ, PGⅠ/Ⅱ level and other indexes. The high risk assessment model of gastric cancer was constructed. Results: The receiver operating characteristic (ROC) curve showed that the maximum area under the curve was 0.736 when PGⅠ was 43.7 μg/L. When PGⅠ/Ⅱ was 2.2 μg/L, the maximum area under the curve was 0.780. PG=43.7 μg/L and PGⅠ/Ⅱ=2.1 μg/L were the best screening critical values. Gender, drinking water type, HP infection, family history, PGⅠ, PGⅠ/Ⅱ level and age were independent risk factors for gastric cancer in the patients (P<0.05). On the basis of logistic regression analysis, the risk factors were assigned and the scoring model was established: Y=A×age +30×gender +30×drinking water +30×HP (+) +50×family history +B×PG level (35-45 years: A=20; 46-55 years: A=40; 56-65 years: A=70; ≥66 years: A=80. PGⅠ≤43.7 μg/L and PGⅠ/Ⅱ>2.1 μg/L: B=10; PGⅠ>43.7 μg/L and PGⅠ/Ⅱ≤2.1 μg/L: B=30; PGⅠ≤43.7 μg/L and PGⅠ/Ⅱ≤2.1 μg/L: B=80). According to the construction model, the scores of the two groups were verified. The results showed that the score of case group (209.78±46.98) was significantly higher than that of the control group (122.37±56.37) (χ ² =13.962, P<0.001). The ROC curve showed that the maximum area under the curve was 0.876 when the critical value was 156, and the Youden index was 0.595. After Hosmer-Lemeshow test, it was found that the fitting degree of the model was better. Conclusion: According to the scoring model of gastric cancer, the patients whose score ≥156 with gastrointestinal discomfort, should be regarded as high-risk population, and it is recommended to have a follow-up gastroscopy at least once a year.

Key words: Gastric neoplasms, Receiver operating characteristic curve, Risk factors, Helicobacter pylori