Screening for lung cancer with low-dose spiral CT: Results in 150 asymptomatic subjects

BACKGROUND AND OBJECTIVE: Our aim is to present initial baseline data from a screening trial on low-dose spiral computed tomography (CT). We describe enrollment criteria and a diagnostic algorithm based on initial low-dose CT findings. SUBJECTS AND METHOD: From September 2000 to May 2001, 150 asymptomatic smokers (age range 40-78 years; mean 55 years) were studied using non-enhanced low-dose spiral CT of the chest. Repeated short-term high resolution CT follow-up was performed for non-calcified pulmonary nodules smaller than 10 mm in diameter. Non-calcified pulmonary nodules 10 mm or larger were considered as potentially malignant and a complementary positron emission tomography (PET) exam was recommended. RESULTS: 54 non-calcified pulmonary nodules were found in 34 out of 141 (24.15%) symptom-free subjects. The diameter was 5 mm or shorter in 24 participants (70.6%), 6-10 mm in 7 (20.6%) and longer than 10 mm in 3 (8.8%) individuals. One patient with a non-calcified pulmonary nodule of at least 10 mm underwent a complementary PET exam, which was positive. Biopsy of this nodule demonstrated lung cancer (squamous cell carcinoma). CT follow-up over one year was decided in the other two subjects having non-calcified pulmonary nodules longer than 10 mm, as no radiographic signs indicative of malignancy were observed in the baseline scan. CONCLUSION: Following this low-dose CT based screening programme, detection of early-stage lung cancer in asymptomatic subjects at high risk of developing the disease is feasible. Further studies are however necessary to pursue more definitive results.