Basic Overview: Precancerous lesions are lesions that occur in the area prior to the development of cancer and lead to cancer. Precancerous cervical lesions are atypical hyperplasia of the cervix. The occurrence and development of cervical cancer has a gradual evolution process, which can last from several years to several decades. It is generally believed that this evolution process goes through several stages: hyperplasia, atypical hyperplasia, carcinoma in situ, early infiltration, and invasive carcinoma. The four major symptoms are: bleeding after sex, which is a symptom found in 70%-80% of cervical cancer patients; and cervical erosion. Young women who have cervical erosion for a long time or still have cervical erosion after menopause should pay attention to it; thirdly, contact bleeding, bleeding after sex or uterine bleeding after gynecological internal examination are signs of cervical precancer; fourthly, mixed blood in the leucorrhoea, except for uterine bleeding caused by IUD, women with mixed blood in the leucorrhoea for a long time should be examined in time. 80% of cervical precancerous lesions can be cured through early detection and early treatment. Diagnostic methods: 1. Cervical cytological examination (1) Pap smear: It is the traditional cervical cytological examination, and its wide application has successfully reduced the incidence and mortality rate of cervical cancer by about 70% in the past 50 years. However, due to the high rate of false negatives and missed diagnoses, Pap smear no longer meets the needs of today’s medical services and is gradually being replaced by more advanced screening methods. (2) TCT cervical thin layer liquid-based cytology: It is a new cytology technology invented in the late 1990s, which can significantly improve the detection rate of cervical cancer and precancerous lesions, and is the most widely used cervical cytology examination method in the world. 2.Human papillomavirus HPV test: to detect high-risk incidence group and for further examination. 3.Electronic colposcopy. 4.Cervical iodine test examination. 5.Cervical and cervical canal biopsy. 6.Cervical conization pathological examination. Disease prevention: 1. Strengthen health education, raise awareness of prevention, avoid premature sex, eliminate sexual confusion. 2, regular gynecological examination, married women are recommended to do cervical cytology examination at least once every two years, and further pathological examination should be done if problems are found. 3. For cervical lesions and reproductive system infections that have been detected, especially HPV infections, corresponding treatment measures should be actively taken to prevent the occurrence and development of cervical cancer. Cervical precancer examination: First step: TCT thin-layer liquid-based cytology test Firstly, the most advanced thin-layer liquid-based cytology technology (TCT) is used to observe cervical cells under a microscope to see whether there are abnormalities in cervical cells. This is because cervical cancer starts from the earliest heterogeneity of cervical cells. Alternatively, if financial conditions allow, HPV testing can also be performed, which is a bit more accurate. Second step: electronic colposcopy After TCT thin layer liquid-based cytology test, if abnormal cervical cells are found, colposcopy is required. Under electronic colposcopy with high magnification of 40 times, it is important to observe the subtle changes in the surface layer of cervical precancerous area, which is valuable for early detection and early diagnosis of cervical cancer and precancerous lesions. Third step: histopathological testing If abnormalities are found during colposcopy biopsies should be taken under the guidance of special staining. Under the prompting of colposcopy, multi-point biopsy of the suspected lesions and separate histopathological examination can confirm the diagnosis of cervical lesions. After the above three steps of examination, cervical lesions can be identified and early stage of cervical cancer can be detected and prevented before it happens.