Early lung cancer action project: overall design and findings from baseline screening.

BACKGROUND

The Early Lung Cancer Action Project (ELCAP) is designed to evaluate baseline and annual repeat screening by low radiation dose computed tomography (low-dose CT) in persons at high-risk for lung cancer. The authors report on the baseline screening experience. For full evaluation of screening, they await the results of annual repeat screening.

METHODS

Using a novel non-comparative design, enrollment of 1000 asymptomatic persons, 60 years of age or older, with at least 10 pack-years of cigarette smoking, no prior cancer, and who were medically fit to undergo thoracic surgery was initiated in 1993. After a structured interview and informed consent, chest radiographs (CXR) and low-dose CT were obtained on each subject. The diagnostic workup of screen-detected noncalcified pulmonary nodules (NCNs) was guided by ELCAP recommendations which included short-term high-resolution CT (HRCT) follow-up for the smallest NCNs.

RESULTS

On low-dose CT at baseline as compared to CXR, NCNs were detected three times as commonly (23% vs. 7%), malignancies four times as commonly (2.7% vs. 0.7%), Stage I malignancies six times as commonly (2.3% vs. 0.4%). Of the 27 CT-detected cancers, 96% (26/27) were resectable; 85% (23/27) were Stage I, 19 (83%) of the 23 were not seen on CXR. Following the ELCAP recommendations, biopsies were performed on 28 of the 233 subjects with NCNs; 27 had a malignant NCN and one had a benign one. Another three individuals underwent biopsy outside of the ELCAP recommendations, all had benign NCNs. No one had thoracotomy for a benign nodule.

CONCLUSIONS

The estimated five-year survival rate of baseline CT-detected malignancies of 60%-80% is a marked improvement over the current rate of 15%. Although false-positive CTs are common, they can be managed with minimal use of invasive diagnostic procedures.