[Epidemiology of lung tumors]

Approximately one out of 500 chest radiographs shows the incidental finding of a solitary pulmonary nodule and almost one half of these pulmonary lesions are caused by a tumor. Unfortunately, only 2% to 5% of all lung tumors are of benign origin, e. g. lipoma, fibroma, hamartoma, and chondroma, and the majority are malignant neoplasms, most commonly primary lung cancer followed by metastases of extrapulmonary primary carcinomas. Thus, a careful diagnostic work up of solitary pulmonary nodules, including histological diagnosis, is mandatory for an adequate management and treatment of patients with pulmonary lesions. Despite all recent improvements of treatment modalities, lung cancer continues to be a major cause of morbidity and mortality among malignant diseases worldwide. The prognosis of affected patients is still very poor and a 5-years survival rate of only 14% makes lung cancer the number one cause of death due to cancer in Switzerland. Active and passive tobacco smoking are by far the best known risk factor for the development of lung cancer, but there are severe other probably less known factors that may increase the individual risk for malignant neoplasms of the lung. These risk factors include e. g. exposure to natural ionic radiation, consisting of terrestrial radiation and indoor radiation caused by radon gas, exposure to respirable dust and Diesel engine emissions, asbestos, and polycyclic aromatic hydrocarbons. In the majority of cases, the latency between exposure and development of cancer is years to decades and the person concerned was occupationally exposed. Therefore, a detailed evaluation of a patient's medical and occupational history is needed. Due to its poor prognosis, prevention and early diagnosis of lung cancer is crucial to improve our patients' outcome. Good knowledge of epidemiology and aetiology of pulmonary tumors is the key to preventive measures and identification of individuals at increased risk for lung cancer. An overview will be provided on the epidemiology of lung tumors and predominantly preventable risk factors for lung cancer.