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.