Screening for Lung Cancer Using Low-Radiation Dose Computed Tomography

Lung cancer is a leading cause of cancer death. Currently there are no major health organizations endorsing lung cancer screening. This is primarily based on the results of four randomized, controlled trials conducted in the 1970s comparing screening using sputum cytology (some with chest radiography as well) with no screening for lung cancer. The Early Lung Cancer Action Project (ELCAP), initiated in 1992, demonstrated the enormous potential of low radiation dose (low-dose) helical CT to detect lung cancer at an early stage, and its superiority over conventional chest radiography. As compared to the initial baseline screening evaluation, ELCAP has shown that on repeat annual screening, there is a substantially lower number of false-positive studies and a higher percentage of malignancy among the newly detected lung nodules. Adherence to the diagnostic algorithm, which included the use of high-resolution computed tomography (HRCT) in the follow-up of lung nodules, enabled confirmation of lung cancer within short time intervals while minimizing unnecessary interventional procedures. The use of computer-generated three-dimensional image reconstruction can be helpful in the detection of nodular growth after a follow-up interval as short as 1 month. The role of low-dose CT in screening for lung cancer is currently under investigation but seems promising. Additional techniques, such as the use of biomarkers, may also aid in early detection of lung cancer. The precise role of these techniques relative to low-dose CT screening continues to evolve.