”Cervical erosion” is a wrong diagnostic term
The term “cervical erosion”, a term used in obstetrics and gynecology, has been used to diagnose “chronic cervicitis” for more than 100 years, since 1850 until the 1980s. With the advancement of medical science, especially in the last decade, the etiology and pathogenesis of cervical cancer and its precancerous lesions have been studied in depth, and a large number of evidence-based medical findings have been obtained worldwide, indicating that persistent infection (at least more than 2 years) with about 15 oncogenic human papillomaviruses (HPV) is closely associated with the development of cervical cancer and its precancerous lesions. Cervical erosion, once thought to be associated with cervical cancer, is now considered to be unrelated to the development of cervical cancer.
In the 1980s, the term “cervical erosion” was removed from American obstetrics and gynecology monographs and textbooks and was replaced by the term “cervical ectopy”.
Unfortunately, to date, a significant number of obstetricians and gynecologists in China continue to use the term “cervical ectopy”, providing unnecessary treatment and possible harm to women who have “cervical ectopia” but no cervical disease.
1. The essence of “celiac disease” is cervical ectropion
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 network of blood vessels beneath; rough because the columnar epithelium is fused with each other in a villi or granular form. 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 for decades from adolescence onwards.
2. Squamous epithelial metaplasia and the type of cervical transformation zone
The epithelium covering the cervix is composed of columnar epithelium, metaplastic epithelium and primitive squamous epithelium from the inside to the outside of the cervical canal. The ectocervix is often the area of the transformation zone (TZ). The transformation zone is composed of active chemosynthetic epithelium.
Ectocervical columnar epithelial migration and squamous epithelial metaplasia: estrogen action on the cervix is known to cause the columnar epithelium to move 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 metaplasia occurs in approximately 60% of the cervical columnar epithelium during a woman’s lifetime.
Recent studies have shown that the chemosquamous epithelium of the cervix is particularly susceptible to the oncogenic form of HPV! but the cause is unknown. This explains why the vast majority of cervical cancers and their precancerous lesions are located within the transformation zone rather than outside.
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 on long-term oral contraceptives, the zone of transformation is mostly located at the external opening of the cervical canal (formerly known as “cervical erosion”), where squamous epithelial metaplasia is very active.
To determine the anatomical location of cervical lesions, colposcopy distinguishes three types of transformation zones.
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 located outside/partially inside the cervical canal.
Type III transformation zone (unsatisfactory colposcopy): the transformation zone is located entirely within the cervical canal.
The vast majority of CIN or cervical cancer is located within the transformation zone. The purpose of identifying the type of transformation zone is to determine if 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.
3. The treatment of “cervical erosion” is against medical ethics
For decades, China has advocated physiotherapy such as electric ironing, laser and freezing for moderate and severe cervical erosion. In recent years, LEEP (i.e. cervical electrosurgical loop excision) technology, which is specifically used 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, this treatment has a tendency to further expand, which is very worrying!
What are the dangers of treating “celiac disease”? First of all, the treatment of “celiac disease” is against medical ethics, as the women treated may not have cervical disease, and the physical and psychological burden and economic loss that treatment brings to women is unwarranted! Second, treatment without cervical screening may miss invasive cervical cancer or high-grade precancerous lesions (CIN3/AIS), which is dangerous for women with the disease. In addition, treatment may 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, and impaired cervical function leading to miscarriage or premature delivery during pregnancy.
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 identified 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 surface loss of the overlying epithelium (i.e. true erosion: its pathological significance is consistent with superficial ulcers) or erosive, cavernous ulcers, and bleeding or contact bleeding on the surface of the cervix. A few cervices with smooth appearance may also conceal lesions in the cervical canal, and it is usually difficult to determine the presence of cervical disease by visual observation alone.
4.The diagnosis method of cervical precancerous lesions is “three-step technique”.
Cervical invasive carcinoma originates from the squamous or glandular epithelium of the uterine cervix. The early stage of its natural history is the persistent infection of high-risk HPV, which leads to the slow destruction of the mature differentiation process of the epithelium in the migratory zone of the cervix, and this early stage is called cervical precancerous lesion (≥ CIN2/AIS). The primary method of cervical screening is cervical cytology, with ancillary methods such as high-risk HPV
DNA testing. The diagnosis of cervical invasive carcinoma and its high-grade precancerous lesions (≥CIN2/AIS) is based on the “three-step technique”: cervical cytology, colposcopy and histopathology.
There is only one way to treat high-grade precancerous lesions: removal of the entire lesion.