Early lung cancer detection using spiral computed tomography and positron emission tomography.

Rationale: Lung cancer screening using computed tomography (CT) is effective in detecting lung cancer in early stages. Concerns regarding false-positive rates and unnecessary invasive procedures have been raised.

Objective: To study the efficiency of a lung cancer protocol using spiral CT and F-18-fluorodeoxyglucose positron emission tomography (FDG-PET).

Methods: High-risk individuals underwent screening with annual spiral CTs. Follow-up CTs were done for noncalcified nodules of 5 mm or greater, and FDG-PET was done for nodules 10 mm or larger or smaller (> 7 mm), growing nodules.

Results: A total of 911 individuals completed a baseline CT study and 424 had at least one annual follow-up study. Of the former, 14% had noncalcified nodules of 5 mm or larger, and 3.6% had nodules of 10 mm or larger. Eleven non-small cell lung cancers (NSCLC) and one small cell lung cancer (SCLC) were diagnosed in the baseline study (prevalence rate, 1.32%), and two NSCLCs in the annual study (incidence rate, 0.47%). All NSCLCs (92% of prevalence cancers) were diagnosed in stage I (12 stage IA, 1 stage IB). FDG-PET was helpful for the correct diagnosis in 19 of 25 indeterminate nodules. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG-PET for the diagnosis of malignancy were 69, 91, 90, and 71%, respectively. However, the sensitivity and negative predictive value of the screening algorithm, which included a 3-month follow-up CT for nodules with a negative FDG-PET, was 100%.

Conclusion: A protocol for early lung cancer detection using spiral CT and FDG-PET is useful and may minimize unnecessary invasive procedures for benign lesions.