Meeting Abstracts
» Screening for Lung Cancer with CT: Prospective Cohort Study

PURPOSE: To study a cohort at high-risk for lung cancer with annual CT screening.

MATERIALS AND METHODS: We enrolled 1,520 individuals aged 50 years or older who had smoked 20 pack-years or more in a prospective cohort study. Participants underwent four annual (one prevalence and three incidence) low-dose CT scans of the chest and upper abdomen. Over 96% of subjects returned for annual incidence studies.

RESULTS: 3,134 uncalcified lung nodules were identified in 1,086 participants (71.4%). Fifty-six lung cancers were diagnosed. CT alone detected 50 cases and sputum cytology alone, 2 (4 were interval cancers). Cell types were squamous cell, 15; adenocarcinoma, 30 (9/29 were bronchioloalveolar); large cell, 1; non-small cell, 5; small cell, 5. The mean size of the non-small cell cancers detected by CT was 15 mm. Prevalence cancer stages (n=29) were IA, 18; IB, 2; IIA, 4; IIIA, 2; IV, 1; limited, 2. Incidence cancer stages (n=23) were IA, 13; IB, 1; IIB, 1; IIIA, 2; IV, 2; limited, 1; unstaged, 3. Interval cancer stages (n=4) were IA, 1; IV, 1; limited 2. Thirty-two (63%) of the 51 non-small cell cancers were stage IA at diagnosis. Thirty-seven participants have died; ten from lung cancer (7 incidence, 2 prevalence and 1 interval). We identified 2,353 incidental findings in 1154 (75.9%) subjects; 727 were judged to be of moderate to high importance (further testing or procedures indicated).

CONCLUSION: Most lung cancers detected were early-stage. The proportion of participants with benign nodules and incidental findings was high.

AUTHORS: Stephen J. Swensen, M.D., James R. Jett, M.D., Thomas E. Hartman, M.D., David E. Midthun, M.D., Magdalen A. Clemens, C.C.R.P.

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