Precancerous conditions of the cervix are a number of pathological conditions that, under certain conditions, can transform into cervical cancer. These include dysplasia, leukoplakia with atypia, erythroplakia, adenomatosis. In most women, precancerous conditions of the cervix are erased; sometimes they can be accompanied by watery whites, contact or intermenstrual bleeding. They are diagnosed on the basis of examination of the cervix in mirrors, colposcopic picture, results of oncocytology and biopsy, HPV typing. Depending on the nature and stage of precancerous changes, radiosurgical, cryogenic or laser destruction of the pathological focus, cervical conization or hysterectomy can be performed.
General information
Precancerous cervical disease is dysplastic processes in the vaginal part of the cervix with a high risk of malignancy. In gynecology, there are background diseases of the cervix (pseudoerosion and true erosion, polyps, simple leukoplakia, endometriosis, ectropion, papillomas, cervicitis) and precancerous. Background pathologies are characterized by normoplasia of epithelial cells – their correct division, maturation, differentiation, rejection.
A distinctive feature of precancerous conditions of the cervix is that they occur with epithelial dysplasia – its hyperplastic transformation, proliferation, violation of differentiation, maturation and exfoliation. However, unlike cervical cancer, all these cellular changes are limited to the limits of the basement membrane. In most cases, precancerous processes develop in the area of background diseases and are often masked by them, which makes timely diagnosis difficult. The average age of patients with precancerous cervix is 30-35 years.
Causes
Currently, the viral theory is recognized as the key concept of the etiopathogenesis of precancerous conditions of the cervix. Epidemiological studies convincingly prove that papillomavirus infection plays a leading role in the development of dysplasia. In the population of women with severe cervical dysplasia, 85-95% are HPV-positive; they mainly have highly oncogenic virus types — 16, 18 and 31. Getting into the body during sexual intercourse, HPV is introduced into the cells of the basal layer of the epithelium. In an infected cell, the virus is able to parasitize in two forms: benign, episomal and intrasomal, stimulating tumor growth. Despite the fact that HPV infects basal cells, cytopathic effects occur primarily in the cells of the surface layer of the cervical epithelium, where viral replication occurs.
The emergence of precancerous cervix contributes to the “commonwealth” of HPV, herpes simplex virus type II, chlamydia and cytomegalovirus infections. The combination of HIV infection and HPV significantly increases the risk of malignancy. The most important factor that increases the likelihood of precancerous conditions of the cervix is the duration of the persistence of the virus.
To a lesser extent than viral agents, the risk of developing background and precancerous pathology of the cervix may be influenced by other probable risk factors. Thus, a number of authors associate cervical intraepithelial neoplasia (CIN) with smoking. It has been proven that women who smoke more than 20 cigarettes a day for 20 years have a five-fold increase in the risk of squamous cell dysplasia. The metabolites contained in tobacco smoke penetrate into the cervical mucus and can act both as independent carcinogens and as factors that activate HPV.
The correlation of precancerous conditions of the cervix with long-term use of estrogen-gestagenic oral contraceptives, especially with an increased gestagenic component, has been established. Precancerous conditions of the cervix are more often affected by women with a history of early labor, cervicitis, cervical injuries during abortions and childbirth, hormonal and immune homeostasis disorders. Among other risk factors, the early (earlier than 16 years) onset of sexual activity, frequent change of sexual partners, occupational hazards, burdened family history of CC are considered. At the same time, a number of studies have shown that prolonged intake of high doses of vitamin C and carotene can cause regression of intraepithelial cervical neoplasia.
Classification
The classification of precancerous conditions of the cervix has undergone repeated revisions and clarifications. One of the latest classifications (1996) identifies benign background changes and precancerous proper. According to her, the background ones include dishormonal (ectopia, endometriosis, polyps), post-traumatic (ectropion, scars, cervical ruptures), inflammatory (erosion, cervicitis) processes.
Precancerous conditions of the cervix, according to colpocervicoscopic and histological examination, are divided into several groups:
- Dysplasia (cervical intraepithelial neoplasia) is the proliferation of atypical cervical epithelium without changing the structure of the stromal layer and surface epithelium. It includes such forms as simple leukoplakia, dysplasia fields, papillary and precancerous transformation zone, precancerous polyps and condylomas. The frequency of degeneration of precancerous cervix into cancer varies in the range of 40-60%, depends on the type of pathology, its localization and duration of the course.
There are mild (CIN-I), moderate (CIN-II) and severe (CIN-III) dysplasia. With mild dysplasia, cells of the deep – basal and parabasal layers (less than 1/3 of the thickness of the multilayer epithelium) are affected; atypical cells are absent. Moderate dysplasia is characterized by changes in 1/3-2/3 of the thickness of the epithelial layer; atypia is not observed. In severe dysplasia, hyperplastic cells account for more than 2/3 of the thickness of the epithelial layer, there are cells of atypical structure.
- Leukoplakia with atypia is morphologically characterized by keratinization of the surface epithelium, proliferation of basal layer cells with atypism phenomena, lymphoid infiltration of subepithelial connective tissue. In 75% of cases, it gives rise to invasive CC.
- Erythroplakia is a precancerous disease of the cervix, occurring with atrophy of the superficial and intermediate layer of the multilayer squamous epithelium; hyperplasia of the basal and parabasal layers with the presence of atypical cells.
- Adenomatosis is an atypical hyperplasia of the endocervix glands, resembling endometrial hyperplasia. Against the background of adenomatosis, glandular forms of cancer can develop.
Symptoms
A feature of the course of precancerous conditions of the cervix is its asymptomatic or nonspecific clinical manifestations. Basically, this group of pathologies is detected during gynecological examination and colposcopy with a Schiller sample.
Cervical dysplasia has no independent symptoms. Only with the addition of a secondary infection can a clinic of vaginitis or cervicitis develop (whiteness, burning, contact spotting). With changes due to hormonal imbalance, menstrual cycle disorders by the type of meno- and metrorrhagia are possible. There are no pain sensations.
Most women with cervical leukoplakia consider themselves practically healthy, only a small part notes the presence of abundant whites and contact bloody discharge. The colposcopic picture is very pathognomonic: the site of leukoplakia is defined as a whitish pearlescent spot. It is possible to differentiate the simple and atypical form of the disease only after histological examination of the biopsy. Patients with erythroplakia may be disturbed by sticky yellowish discharge. Colposcopy reveals dark red areas with uneven borders, raised above the unchanged mucosa.
Cervical warts and adenomatous polyps are found mainly during colposcopic examination. In the presence of secondary changes in them caused by ulceration, traumatization, etc., the appearance of blood secretions is possible.
Diagnostics
The algorithm for diagnosing precancerous conditions of the cervix is developed in detail and includes a series of instrumental and laboratory studies that allow not only to determine the type of precancerous, but also the degree of dysplasia.
During a visual examination of the vaginal portion of the cervix with the help of mirrors, the gynecologist evaluates the shape of the external pharynx, the color of the mucosa, the nature of the secretion, visible pathological processes. As part of the gynecological examination, smears are taken from the surface of the cervix for oncocytological examination (PAP test). When identifying suspicious areas of the cervix, the next step is a simple colposcopy, if necessary, an extended study with drug tests (Schiller samples, etc.). Each form of background and precancerous conditions of the cervix has its own colposcopic picture, therefore, differential diagnosis of pathologies is possible at this stage. To detect changes in the endocervix, cervicoscopy is used.
Further tactics of examination of patients with suspected precancerous conditions of the cervix involves the implementation of a targeted biopsy of the cervix and curettage of the cervical canal. Based on the received histological conclusion, the precancerous condition is finally confirmed or excluded and its form is determined. Additional clinical and laboratory diagnostics may include PCR testing for HPV with typing, pelvic ultrasound etc.
Treatment
The approach to the treatment of precancerous conditions of the cervix is differentiated and phased. The purpose of therapy is the radical removal of pathologically altered tissues, the elimination of provoking and concomitant factors (treatment of HPV, immune and hormonal imbalances, inflammatory processes). In accordance with the identified violations, etiotropic anti-inflammatory therapy (antiviral, antibacterial, immunomodulatory, interferon-stimulating, enzyme preparations) is prescribed. Correction of vaginal biocenosis, vitamin therapy, if necessary, hormone therapy is carried out.
The choice of surgical treatment of precancerous conditions of the cervix depends on the degree of cellular dysplasia. With CIN I-II, especially in nulliparous patients, a sparing physical effect on pathological foci is possible: diathermocoagulation, radiosurgical treatment, laser vaporization, cryodestruction. With CIN II-III, radical surgical intervention is indicated in the volume of excision or conization of the cervix, cone amputation or hysterectomy (removal of the uterus). With polyps of the cervical canal, they are removed from the SDC.
After the cure of precancerous conditions of the cervix, control colpocervicoscopy and oncocytology are repeated every 3 months during the first year and twice a year during the second. Relapses are rare, but it is known that their percentage is higher in HPV-infected women. Prevention of precancerous conditions of the cervix involves a wide coverage of the female population by screening programs, vaccination against CC. An important role is played by the behavior of the woman herself: the use of barrier contraception during casual contacts, smoking cessation, timely treatment of background diseases.
