Approximately 80% of all malignant lung tumors are non-small cell lung cancer (NSCLC). In 2014 approximately 43,000 new cases of NSCLC were diagnosed in Germany, of which slightly more than one third were in females (15,000). Adenocarcinoma and squamous cell carcinoma are the two most common histological subtypes. The proportion of adenocarcinomas has increased in recent years in both sexes, a trend that can also be observed internationally. The most important risk factor is tobacco smoking, with adenocarcinomas occurring more frequently in non-smokers than other histological subtypes. Therefore, other risk factors, such as radon or particulate matter, are likely to play a greater role in relative terms. Some subtypes of NSCLC show clear differences in the distribution of the tumor stages and in the survival rates.