What is the nature of “cervical erosion”? Domestic textbooks used to describe “cervical erosion” as a congested, red, granular appearance of the external cervical opening. There are two types of cervical epithelium during embryogenesis: primitive squamous epithelium and columnar epithelium. Before puberty, the primitive squamous-columnar junction is located anywhere inside or outside the cervical canal or in the vaginal vault. After puberty, under the influence of estrogen, the cervical volume grows rapidly and greatly exceeds the body of the uterus, and ectropion of the cervix ensues. The ectropion exposes the cervical columnar epithelium to the ectocervix, which is “red and rough”: red because the columnar epithelium is arranged in a single layer with a rich vascular network underneath; rough because the columnar epithelium is fused with each other in a villi or granular shape. In the past, “red roughness” of the ectocervix was mistakenly described by the term “cervical erosion” as “absence of overlying epithelium”, which is an inappropriate and wrong term and should be abandoned. The essence of “cervical erosion” is cervical ectropion, a physiological phenomenon that lasts from adolescence to the next few decades. Second, “cervical erosion” – cervical transformation zone and squamous epithelial metaplasia The epithelium covering the cervix is composed of the columnar epithelium, the metaplastic epithelium and the primitive squamous epithelium, from the inside to the outside of the cervical canal, in that order. The ectocervix is often the area of the cervical transformation zone. The transformation zone is composed of active chemosynthetic epithelium. 1. Ectocervical columnar epithelium and squamous epithelial metaplasia: estrogen is known to act on the cervix to move the columnar epithelium from inside the cervical canal to outside the cervical canal. When the columnar epithelium is exposed to the acidic environment of the vagina, it causes the reserve cells located below the columnar epithelium to be exposed, proliferate, differentiate, and then form a thin, multilayered pseudostratified layer (i.e., chemosynthetic epithelium). This physiological process of transformation from cervical columnar epithelium to squamous epithelium is called squamous epithelial metaplasia, which takes about 1-3 weeks and is irreversible. Squamous epithelial transformation occurs in about 60% of women during their lifetime. 2. Recent studies have shown that the chemosquamous epithelium of the cervix is particularly susceptible to oncogenic HPV! However, the reason for this is unknown. This explains why the vast majority of cervical cancers and their precancerous lesions are located within the transformation zone rather than outside. 3. Type of transformation zone and anatomical location of cervical lesions: The cervical transformation zone changes dynamically (i.e., moves up and down) throughout a woman’s life. In women who are embryonic (placental hormone action), adolescent, pregnant or taking oral contraceptives for a long time, the transformation zone is mostly located at the external opening of the cervical canal (old name “cervical erosion”), where the squamous epithelium is very active. To determine the anatomical location of cervical lesions, colposcopy distinguishes three types of transformation: type I transformation zone (satisfactory colposcopy): the transformation zone is located entirely outside the cervical canal; type II transformation zone (unsatisfactory colposcopy): the transformation zone is partially outside/partially inside the cervical canal; type III transformation zone (unsatisfactory colposcopy): the transformation zone is entirely inside the cervical canal. CIN or cervical cancer is mostly located within the transformation zone. Identifying the type of transformation zone is to determine whether the cervical lesion is located inside, outside, or both inside and outside the cervical canal? Understanding the type of transformation zone and the mechanism of squamous epithelial metaplasia is a useful basic knowledge for clinicians to identify the pathophysiological changes of the cervix and to make differential diagnosis of cervical diseases. What are the dangers of treating “cervical erosion”? For decades, physical therapy such as ironing, laser and freezing has been advocated for moderate and severe cervical erosion in China. In recent years, the LEEP (cervical electrosurgical loop excision) technique, which is used specifically for the treatment of cervical pre-cancerous lesions (CIN) in western developed countries, has also been used for the treatment of cervical erosion. Driven by economic interests, there is a tendency to further expand this treatment. What are the dangers of cervical erosion treatment? First of all, the treatment of “celiac disease” is against medical ethics, as the woman being treated may not have cervical disease, and it is unethical to bring physical and mental burden and economic loss to the woman due to the treatment! Secondly, treatment without cervical screening may miss invasive cervical cancer or high grade precancerous lesions, which is dangerous for women with the disease. In addition, treatment may also cause harm such as adhesions or atresia of the ectocervix, trauma leading to “cervical inflammation” or “cervical endometriosis” causing post-coital bleeding or prolonged leukorrhea, impaired cervical function leading to miscarriage or premature birth during pregnancy, etc. Cervical cancer has been known for more than 200 years and is the most common malignant tumor in less developed countries and regions. In most areas of China, due to limited medical conditions, clinicians are used to determine the presence or absence of cervical disease by visual observation only. Only a few cervical invasive cancers can be recognized by the naked eye. In typical invasive carcinoma of the cervix, the anatomical appearance is mostly deranged, with irregular or cauliflower-shaped growth of cancerous tissues, and the surface is mostly accompanied by loss of the overlying epithelium (i.e. true erosion: its pathological significance is consistent with superficial ulcers) or erosive, cavernous ulcers, and there is often bleeding or contact bleeding on the surface of the cervix. In contrast, a smooth-appearing cervix was generally perceived as healthy. These perceptions are wrong when revisited with today’s evidence-based medical thinking. It is often difficult to determine the presence of cervical disease by visual observation alone. Pre-cancerous lesions of the cervix are diagnosed by the “three-step technique” Invasive cervical cancer originates from the squamous or glandular epithelium of the cervix. The early stage of its natural history is the persistent infection of high-risk HPV, which leads to the slow destruction of the maturation and differentiation process of the epithelium in the migratory zone of the cervix, and this early stage is called cervical precancerous lesions. The main method of screening for cervical cancer is cervical cytology, and the secondary method is high-risk HPVDNA testing. The method used to confirm the diagnosis of cervical cancer and its high-grade precancerous lesions is the “three-step technique”: cervical cytology, colposcopy and histopathology. There is only one treatment for high-grade precancerous lesions: removal of the entire lesion. The focus of cervical cancer prevention and treatment is on early detection of cervical cancer and its high-grade precancerous lesions and standardized treatment.