Lung cancer screening with CT: Mayo Clinic experience

PURPOSE: To evaluate a large cohort of patients at high risk for lung cancer by using screening with low-dose spiral computed tomography (CT) of the chest. MATERIALS AND METHODS: A prospective cohort study was performed with 1,520 individuals aged 50 years or older who had smoked 20 pack years or more. Participants underwent three annual low-dose CT examinations of the chest and upper abdomen. Characteristics of pulmonary nodules and additional findings were tabulated and analyzed. RESULTS: Two years after baseline,CT scanning 2,832 uncalcified pulmonary nodules were identified in 1,049 participants (69%). Forty cases of lung cancer were diagnosed: 26 at baseline (prevalence) CT examinations and 10 at subsequent annual (incidence) CT examinations. CT alone depicted 36 cases: sputum cytologic examination alone, two. There were two interval cancers Cells types were as follows squamous cell tumour, seven, adenocarcinoma or bronchioloalveolar carcinoma, 24 large cell tumour, two, non-small cell tumour, three, small cell tumour, four. The mean size of the non-small cell cancers detected at CT was 15.0 mm. The stages were as follows: IA, 22; IB, three; IIA, four; IIB, one; IIIA, five; IV, one: limited small cell tumour, four. Twenty-one (60%) of the 35 non-small cell cancers detected at CT were stage Ia at diagnosis. Six hundred ninety-six additional findings of clinical importance were identified. CONCLUSION: CT can depict early stage lung cancers. The rate of benign nodule detection is high. ((C)) RSNA, 2003.