There are many causes of lung cancer, not only smoking can lead to lung cancer, but also other common causes such as environmental pollution, special occupation, chronic infectious diseases of lungs, hereditary factors and malnutrition. 1. Environmental pollution: patients who are in the polluted environment for a long time are also easy to suffer from lung cancer, such as those who are in the environment of smoking for a long time and housewives who inhale oil smoke for a long time. 2. Special occupations: it is mainly seen in occupations with long-term exposure to asbestos, inorganic arsenic, coal tar and other substances, as well as those who are engaged in radioactive occupations, which have higher probability of suffering from lung cancer. 3. Chronic infectious diseases of the lungs: chronic infectious diseases of the lungs, such as tuberculosis and bronchial dilatation, can easily lead to the gradual metamorphosis of bronchial epithelium into squamous epithelium, which in turn can cause lung cancer. 4. Hereditary factors: lung cancer is hereditary to a certain extent, if there are patients with lung cancer in the family, the probability of patients suffering from lung cancer is relatively high. 5. Malnutrition: those who lack vitamin A, carotene and other related trace elements in their diet for a long time are more likely to suffer from lung cancer. Smoking is a causative factor of lung cancer, but it is not an absolute factor. For non-smokers, the above mentioned factors may also lead to lung cancer. If lung cancer is detected, please go to the hospital in time to avoid delaying the disease.