Decisions about the treatment of a patient with lung cancer depend on the clinical stage of the disease, morphological diagnosis, examination of predictive markers and overall clinical condition; the wishes of a well-informed patient must also be taken into account. Accurate diagnosis is essential for the future of a patient with lung cancer. The epidemiology of lung cancer is related to cigarette consumption. The risk of the disease increases with the number of cigarettes smoked. The relative risk for smokers is 22.4, for very heavy smokers with a load of more than 25 packets, it can reach up to 50. Most cases of lung cancer are caught in the advanced stages of the disease, when surgery and sometimes other active treatments are no longer possible. Searching for lung cancer in at-risk groups is essential for reducing lung cancer mortality, leading to the detection of the disease at a low stage when the tumor is operable.