Early detection of lung cancer: Clinical perspectives of recent advances in biology and radiology

Lung cancer is the most common cause of cancer death in developed countries , The prognosis is poor, with less than 15% of patients surviving 5 years a fter diagnosis. The poor prognosis is attributable to lack of efficient dia gnostic methods for early detection and lack of successful treatment for me tastatic disease. Most patients (>75%) present with stage III or IV disease and are rarely curable with current therapies. Within the last decade, rap id advances in molecular biology, pathology, bronchology, and radiology hav e provided a rational basis for improving outcome. These advancements have led to a better documentation of morphological changes in the bronchial epi thelium before development of clinical evident invasive carcinomas, This ha s changed our concept of lung carcinogenesis and emphasized the multistep c arcinogenesis approach on several levels. Combined with the technical devel opments in bronchoscopic techniques, e.g., laser-induced fluorescence endos cope (LIFE) bronchoscopy, we now have improved methods to localize preinvas ive and early-invasive bronchial lesions. With the LIFE bronchoscope, a new morphological entity (angiogenic squamous dysplasia) has been recognized, which might be an important biomarker and target for antiangiogenic chemopr eventive agents. To reduce the mortality of lung cancer, these new technolo gies have been taken into the clinic in different scientific settings. The use of low-dose spiral computed tomography in the screening of a high-risk population has demonstrated the possibility of diagnosing small peripheral tumors that are not seen on conventional X-ray, A shift in the therapeutic paradigm from targeting advanced clinically manifest lung cancer toward asy mptomatic preinvasive and early-invasive cancer is occurring. The present a rticle reviews the recent advances in the diagnosis of preinvasive and earl y-invasive cancer to identify biomarkers for early detection of lung cancer and for chemoprevention studies.