In situ cervical cancer, also known as cervical carcinoma in situ, does not require chemotherapy, and was previously included in cervical severe intraepithelial neoplasia, or CIN3, a term that many people, including professionals, continue to use for habitual reasons.CIN3 includes severe atypical hyperplasia and carcinoma in situ, both of which have heterogeneous cell proliferation reaching more than 2/3 of the epithelium, and cervical carcinoma in situ, which has heterogeneous cells Almost or all of them occupy the whole epithelial layer, but do not break through the basement membrane. Therefore, cervical carcinoma in situ still belongs to the category of precancerous lesions. Although there is a word “cancer” in the name, it is not a malignant disease and is essentially different from the real cancer as usually understood. The risk of cervical carcinoma in situ developing into invasive carcinoma is significantly higher than other precancerous lesions, so it needs to be treated actively. Young people with fertility requirements can undergo cervical conization, i.e. LEEP or cold knife, and in older people without fertility requirements can undergo extra-fascial total hysterectomy without chemotherapy, and the cure rate can reach almost 100%. After surgery, close follow-up is needed, because due to pathological sampling, there are very few early invasive carcinomas mixed with in situ carcinomas, and also if the cervical conization is relatively insufficient, it is easy to recur.