Pastor A, Menéndez R, Cremades M J, Pastor V, Llopis R, Aznar J
Servicio de Neumologia, Hospital Universitario La FE, Valencia, Spain.
Eur Respir J. 1997 Mar;10(3):603-9.
The aim of this study was to evaluate the diagnostic value of three tumour markers, squamous cell carcinoma (SCC) antigen, carcinoembryonic antigen (CEA) and CYFRA 21.1, in lung cancer using a Bayesian analysis to obtain the predictive values for different pretest probabilities or prevalences. A cross-sectional study included 94 patients with lung cancer, 40 with benign lung disease, and 40 healthy controls. SCC antigen and CEA were measured in blood samples by microparticle enzyme immunoassay (MEIA), and CYFRA by enzyme-linked immunosorbent assay (ELISA). The results of tumour marker determinations were expressed as percentiles, and showed significantly higher levels in the cancer group than in the two control groups. Taking the 95th percentile of benign lung diseases as the cut-off point (specificity 95%), the following sensitivities were found: SCC 41%, CEA 31% and CYFRA 79%. After a Bayesian analysis, the best results for the three tumour markers were found in prevalences of 30-40%. The highest incremental gain was obtained by CYFRA (at prevalence of 36%, positive and negative predictive value approximately 90%). The three tumour markers were included in a stepwise regression analysis to predict lung cancer, and CYFRA was the only selected variable. We conclude that CYFRA 21.1 may be a useful marker in lung cancer when there is an intermediate pretest probability of disease.
本研究旨在通过贝叶斯分析评估三种肿瘤标志物，即鳞状细胞癌（SCC）抗原、癌胚抗原（CEA）和细胞角蛋白19片段（CYFRA 21.1）在肺癌诊断中的价值，以获得不同检验前概率或患病率下的预测值。一项横断面研究纳入了94例肺癌患者、40例良性肺部疾病患者和40例健康对照者。通过微粒子酶免疫分析（MEIA）检测血样中的SCC抗原和CEA，通过酶联免疫吸附测定（ELISA）检测CYFRA。肿瘤标志物测定结果以百分位数表示，癌症组的水平显著高于两个对照组。以良性肺部疾病的第95百分位数为临界点（特异性95%），得到以下敏感度：SCC为41%，CEA为31%，CYFRA为79%。经过贝叶斯分析，发现三种肿瘤标志物在患病率为30% - 40%时效果最佳。CYFRA获得的增量增益最高（在患病率为36%时，阳性和阴性预测值约为90%）。将这三种肿瘤标志物纳入逐步回归分析以预测肺癌，CYFRA是唯一入选的变量。我们得出结论，当疾病的检验前概率处于中等水平时，CYFRA 21.1可能是肺癌的一种有用标志物。
