Screening for lung cancer: a review and current

Summary Lung cancer is the leading cause of cancer death in the USA. The overall 5-year survival rate for patients diagnosed with this disease is estimated at 15%. The major reason that the cure rate is so low is that the great majority of lung tumors are found at late stages. After the disappointing results of the National Cancer Institute sponsored trials in the 1970’s, there was widespread acceptance that screening for lung cancer is not indicated, since none of the randomized screening trials demonstrated a reduction in cancer-related mortality. However, longer follow-up from these early studies does show that individuals who were screened and underwent surgery for early stage lung cancer did experience improved survival. Also, earlier detection has been associated with improved survival for patients with cervical and colon cancer. Some recent studies suggest that the use of newer screening tools may result in improved lung cancer mortality. The objectives of this paper are to review the older prospective screening studies, and to discuss the possible biases and study design flaws that might have affected the outcome of those screening trials. This work will also define populations considered to be at high risk for the development of lung cancer and that should most benefit from screening. The early results of trials employing new techniques for lung cancer screening such as spiral computed tomography, positron emission tomography (PET) scanning and sputum immunocytochemistry for the detection of potential curable lung cancers are presented.