Aoki K, Misumi J, Kimura T, Zhao W, Xie T
Department of Public Health and Hygiene, Hasama, Oita Medical University, Japan.
J Epidemiol. 1997 Sep;7(3):143-51. doi: 10.2188/jea.7.143.
This study was carried out to determine the cutoff levels of serum pepsinogen (PG) I, II and their ratio of PG I/PG II for gastric cancer to establish a better screening system. Optimal cutoff levels for gastric cancer screening using serum pepsinogens were determined using Youden's index. The sensitivity, specificity and Youden's index for gastric cancer cases were calculated according to sex, age and the stage of gastric cancer, and the maximum Youden's index in each category was adopted as the cutoff level for gastric cancer screening using serum pepsinogens. The maximal Youden's index in all gastric cancer cases was 0.37, corresponding to a cutoff level of PG I < 40 (micrograms g/l) and PG I/PG II < 3.5. The sensitivity and specificity for gastric cancer cases of these cutoff levels were 0.50 and 0.87, respectively. In future, better criteria for gastric cancer screening have to be examined with the estimation of Youden's index in addition to other epidemiological methods such as ROC (receiver operating characteristic) curves and/or cost benefit analyses.
本研究旨在确定血清胃蛋白酶原（PG）I、II及其PG I/PG II比值对胃癌的临界值水平，以建立更好的筛查系统。使用约登指数确定了采用血清胃蛋白酶原进行胃癌筛查的最佳临界值水平。根据性别、年龄和胃癌分期计算了胃癌病例的敏感性、特异性和约登指数，并将每类中的最大约登指数作为采用血清胃蛋白酶原进行胃癌筛查的临界值水平。所有胃癌病例中的最大约登指数为0.37，对应PG I < 40（微克/升）和PG I/PG II < 3.5的临界值水平。这些临界值水平对胃癌病例的敏感性和特异性分别为0.50和0.87。未来，除了其他流行病学方法如ROC（受试者工作特征）曲线和/或成本效益分析外，还必须通过约登指数的评估来研究更好的胃癌筛查标准。
