Different lung cancers have different rates of spreading, some types of lung cancer can spread within 1 to 2 months, some may not necessarily spread even after 3 to 5 years. The proliferation rate of lung cancer depends on the pathologic type of lung cancer and the degree of malignancy of the cancer cells. Patients with small cell lung cancer, whose cells are less differentiated and more malignant, are more prone to proliferation, and proliferation and distant metastasis may occur within 1 to 2 months. Patients with squamous lung cancer have less malignant cancer cells and are less likely to spread. They usually grow locally in the lungs to form a mass, which may take 3 to 5 years or even longer to spread. In addition, whether or not to carry out active and suitable treatment will also affect the time of spreading of lung cancer, and the time of spreading can be obviously delayed after effective treatment, or even no spreading occurs. Patients who are diagnosed with lung cancer should have early treatment and maintain good living habits to prolong the survival period.