The main cause of cervical cancer remains the human papillomavirus, causing dysplasia of the cervical epithelium and its cancerous degeneration. The virus is transmitted sexually, and infection occurs with unprotected intercourse. The risk of infection increases with the early onset of sexual activity, numerous sexual partners not only in women, but also in her sexual partner, it decreases with partner monogamy and is virtually absent in virgins.
Factors that contribute to the degeneration of cells are smoking, hormonal disorders, chronic inflammatory diseases of the cervix, local or general decrease in immunity, surgical interventions on the cervix.
Forms of cervical cancer
There are preclinical non-invasive and invasive cervical cancer. If the preinvasive cancer of the cervix does not go beyond the epithelium, the invasive cancer grows not only into the deep layers of the cervix, but also into neighboring organs, and also metastasizes to the lymph nodes and distant organs.
- Preclinical cancer is divided into preinvasive cancer in situ and microinvasive cancer of the cervix (or 1a stage with invasion of the stroma up to 3 mm).
- Invasive cancer of the cervix begins already with the 1b stage, when the invasion of the tumor continues to a depth of more than 3 mm.
- All other stages of cancer are considered invasive: stage 2 when infiltrating an adjacent organ - the vagina of the upper 2/3 or the body of the uterus on one side.
- Stage 3 with infiltration of the entire vagina or transition to the pelvic wall
- 4 stage with the transition to the bladder or beyond the pelvis.
Depending on what cells the malignant tumor consists of, distinguish between different types of cancer, each of which is invasive:
- squamous cell carcinoma of the cervix (with or without keratinization, large or small-celled);
- adenocarcinoma ;
- glandular squamous cell carcinoma;
- adenoid cystic carcinoma;
- undifferentiated cancer.
The lower the differentiation of cancer cells, the harder the disease progresses.
According to the international classification of cervical cancer, preinvasive cancer corresponds to the zero stage according to the clinical classification and Tis according to the international one. Microinvasive corresponds to T1a, and invasive cancer is all subsequent stages of the international classification, while:
- T1b is a cancer limited to the invasion of the cervix alone;
- T2 - the cancer goes beyond the neck corresponding to the 2 stages;
- T3 - the cancer passes to the walls of the pelvis or occupies the entire vagina, corresponding to the 3 stages;
- T4 corresponds to 4 stages according to clinical classification.
Metastasis of invasive cervical cancer
But in the international classification, N- metastases to the lymph nodes were added:
- when N0 they are absent;
- at N1 they happen only in regional lymphonoduses;
- at N2 - in the remote.
In addition to metastases to the lymph nodes in the international classification, there is a designation for distant metastases - M, they are or are - M1, or not - M0. Thus, according to the international classification, the beginning of the invasive process in cervical cancer can be done as follows: T1bN0M0.