Medici T C, Wehrli R, Züllig A
Departement für Innere Medizin, Universität Zürich.
Schweiz Med Wochenschr. 1987 Sep 26;117(39):1448-57.
Chest roentgenography and sputum cytology have been used for the early detection of lung cancer since the beginning of the 1950s. Surprisingly, the yield of screening is sufficiently high. In view of the estimated prevalence of lung cancer of 0.5-2% in high risk persons, the detection rate was 0.32-0.95% in three large randomized clinical trials (Cooperative Pilot Study of the American Cancer Society and Veterans Administration 1969, Canadian study of Grzybowski and Coy 1970, National Cancer Institute Cooperative Early Lung Cancer Detection Program 1984). Screening by chest roentgenogram was superior to sputum cytology. More than 70% of all lung cancers were detected by roentgenography alone. Adding sputum cytology, 10-20% more cancers were found. Lung cancers which were additionally detected by cytology were slowly-growing, central squamous cell carcinomas with good prognosis. The sensitivity of chest X-rays varied between 49 and 77% and the sensitivity of sputum cytology between 33-52%. Specificity was higher, the range being 95-99% for chest X-rays and 96-99% for sputum cytology. The costs per lung cancer detected and treated are very high. To these are added the costs which arise from the evaluation of false positive results. The prognosis of lung cancer detected by screening is good: more patients survive, and they live longer than unscreened patients. The overall 5-year survival of patients screened by chest X-rays and sputum cytology of the NCI-study was 35-55% compared with only 15% of patients not screened. However, whether long survival means reduced mortality is uncertain, since long survival only reflects early detection.
自20世纪50年代初以来，胸部X线摄影和痰细胞学检查一直用于肺癌的早期检测。令人惊讶的是，筛查的检出率相当高。鉴于高危人群中肺癌的估计患病率为0.5%-2%，在三项大型随机临床试验中（美国癌症协会和退伍军人管理局合作试点研究，1969年；加拿大Grzybowski和Coy研究，1970年；美国国立癌症研究所合作早期肺癌检测项目，1984年），检测率为0.32%-0.95%。胸部X线摄影筛查优于痰细胞学检查。所有肺癌中70%以上仅通过X线摄影检出。加上痰细胞学检查，又发现了10%-20%的癌症。通过细胞学检查额外检出的肺癌是生长缓慢的中央型鳞状细胞癌，预后良好。胸部X线检查的敏感性在49%至77%之间，痰细胞学检查的敏感性在33%-52%之间。特异性较高，胸部X线检查的范围为95%-99%，痰细胞学检查的范围为96%-99%。检测和治疗每例肺癌的成本非常高。此外还有对假阳性结果进行评估所产生的成本。通过筛查发现的肺癌预后良好：更多患者存活，且他们比未接受筛查的患者寿命更长。美国国立癌症研究所研究中通过胸部X线和痰细胞学检查进行筛查的患者的总体5年生存率为35%-55%，而未接受筛查的患者仅为15%。然而，长期存活是否意味着死亡率降低尚不确定，因为长期存活仅反映了早期检测。
