Early lung cancer baseline screening: preliminary study with low-dose spiral CT / 中华放射学杂志

ABSTRACT

Objective To evaluate the prevalence rate of pulmonary malignant disease detected by low dose spiral CT in people at high risk of lung cancer. Methods Low dose spiral CT scans and chest radiographs in 300 symptom free volunteers from an on going screening study were prospectively evaluated. The study has enrolled 240 smokers, aged 45 years or older, with at least 10 pack years of cigarette smoking and 60 individuals with chronic obstructive pulmonary disease, and without previous cancer history, who were medically fit to undergo thoracic surgery. Low dose CT scans were performed with SR 7000 scanner using spiral mode, 120 kV, 50 mA, pitch 2, 5mm thickness reconstruction and Lightspeed Plus multi slice scanner using spiral mode, 120 kV, 50 mA, pitch 6 to produce 2.5 mm thick image at 2.5 mm increments. All images were assessed with cine display mode on workstation monitor. Results Non calcified nodules were detected in 56 (19%) participants by low dose CT, compared with 9 (3%) by chest radiography. Malignant disease was detected in 4 (1.3%) by CT and 3 (1%) by chest radiography. All 4 cancers were stage I. Lobar or segmental bronchial abnormalities were detected in 9 (3%) participants by CT. Among them, 3 (1%) proved to be early central lung cancer. No bronchial abnormality was detected by chest radiography. The sensitivity and specificity of cancer screening was 43% and 89%, respectively for chest radiograph, 100% and 80%, respectively for CT. The sensitivity of CT was significantly higher than that of radiograph, whereas the specificity showed no statistical difference. Conclusion Preliminary screening study indicates that low dose CT can greatly improve the likelihood of detection for small non calcified nodules and mild bronchial abnormalities, and thus of peripheral and central lung cancer at an earlier stage.