Carcinoma in situ refers to the depth of invasion of lung cancer, which is limited to the submucosa. The risk of metastasis of carcinoma in situ is extremely low, and it can be cured through radical surgical resection. Postoperative adjuvant chemotherapy, radiotherapy and targeted therapy are not necessary because it is a very early stage. Of course, the diagnosis of lung cancer in situ depends on pathology, especially the pathology after radical surgical resection of the tumor, in order to confirm the diagnosis of lung cancer in situ, and only after lung cancer in situ surgery can it be exempted from postoperative adjuvant therapy and other therapeutic means.