Radiologic screening for lung cancer. present status and future perspectives.

Lung cancer is the most common cause of death from malignancy. This is pred ominantly due to the poor prognosis of the mostly advanced tumor stages at the time of presentation. Prognosis of early, usually asymptomatic stages i s more favourable, particularly in non-small-cell histologic types. Therefo re, early detection using diagnostic tests promises reduction of mortality from lung cancer. Due to its high sensitivity for small pulmonary nodules-t he most common manifestation of early lung cancer-computed tomography appea rs suitable as a screening test particularly as the high radiation exposure associated with standard examination protocols can be significantly reduce d for this purpose. Due to the high prevalence of benign small pulmonary no dules diagnostic algorithms are required for non-invasive classification of detected nodules. Preliminary studies of low-dose CT using algorithms base d on size and density of detected nodules revealed a high proportion of asy mptomatic lung cancers and early resectable tumor stages with a small numbe r of invasive procedures for benign nodules. Prior to a wide application of this technique in clinical routine more data is required as to appropriate inclusion criteria, screening intervals and most importantly the effect of screening on reduction of mortality from lung cancer.