Not all early stage cancers are carcinoma in situ, but carcinoma in situ is one of the early stage cancers. Carcinoma in situ is a relatively special case of cancer. Since the lesion is limited and does not penetrate the basement membrane and does not spread to the surrounding tissues, it belongs to the earliest stage of cancer, and most of the patients can be clinically cured after simple radical surgery, and the postoperative period usually does not need auxiliary radiotherapy, with a five-year survival rate of more than 95% in most of the cases. In addition to carcinoma in situ, early-stage cancers also include stage I cancers, which are staged after carcinoma in situ, i.e., there is infiltration of the basement membrane but the infiltration range is relatively shallow. The treatment of these patients mainly focuses on radical surgery, and only a very small number of patients with high-risk risks need to be given adjuvant radiotherapy after surgery, and the survival rate of patients is relatively high and the prognosis is good. It is recommended that patients actively cooperate with doctors under the guidance of the doctor’s treatment in order to obtain a better prognosis.