Lung cancer screening: a review of available data and current guidelines.

Lung cancer is the leading cause of cancer mortality worldwide. A lack of clinical symptoms in early-stage disease frequently leads to diagnosis at a late stage, and a 15% 5-year survival rate in all patients so diagnosed. This has led to significant interest in effective screening methods to detect early-stage cancers, particularly for high-risk groups, such as current or former smokers. Early clinical trials focused on chest radiograph with or without sputum cytology and failed to show an improvement in mortality with screening. A meta-analysis also failed to show a difference in all-cause mortality. Subsequent protocols compared low-dose computed tomography (LDCT) scan with chest radiograph and documented increased detection of early-stage disease; however, they were not designed to prove a reduction in mortality. The most recent trials have focused on LDCT scans, including the National Lung Screening Trial. Data released from the National Lung Screening Trial demonstrated a statistically significant reduction in lung cancer deaths in patients screened with LDCT scans. When data from the study, including cost-effectiveness, are completely analyzed, they may lead to revision of current lung cancer screening recommendations to include LDCT scans in specific populations at high risk of developing lung cancer.