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Cervical cancer is a disease in which malignant (cancer) cells form in the tissues of the cervix.
The cervix is the lower, narrow end of the uterus (the hollow, pear-shaped organ where a fetus grows). The cervix leads from the uterus to the vagina (birth canal).
Cervical cancer usually develops slowly over time. Before cancer appears in the cervix, the cells of the cervix go through changes known as dysplasia, in which cells that are not normal begin to appear in the cervical tissue. Later, cancer cells start to grow and spread more deeply into the cervix and to surrounding areas.
Human papillomavirus (HPV) infection is the major risk factor for development of cervical cancer. There are now effective vaccines against certain types of HPV.
Symptoms and Diagnosis
Early cervical cancer may not cause noticeable signs or symptoms. Women should have yearly check-ups, including a Pap smear to check for abnormal cells in the cervix. The prognosis (chance of recovery) is better when the cancer is found early.
These and other symptoms may be caused by cervical cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
- Vaginal bleeding.
- Unusual vaginal discharge.
- Pelvic pain.
- Pain during sexual intercourse.
To diagnose cervical cancer, the following procedures may be used:
- Pap smear: A procedure to collect cells from the surface of the cervix and vagina. A piece of cotton, a brush, or a small wooden stick is used to gently scrape cells from the cervix and vagina. The cells are viewed under a microscope to find out if they are abnormal. This procedure is also called a Pap test.
- Colposcopy: A procedure to look inside the vagina and cervix for abnormal areas. A colposcope (a thin, lighted tube) is inserted through the vagina into the cervix. Tissue samples may be taken for biopsy.
- Biopsy: If abnormal cells are found in a Pap smear, the doctor may do a biopsy. A sample of tissue is cut from the cervix and viewed under a microscope by a pathologist to check for signs of cancer. A biopsy that removes only a small amount of tissue is usually done in the doctor´s office. A woman may need to go to a hospital for a cervical cone biopsy (removal of a larger, cone-shaped sample of cervical tissue).
- Pelvic exam: An exam of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. The doctor or nurse inserts one or two lubricated, gloved fingers of one hand into the vagina and the other hand is placed over the lower abdomen to feel the size, shape, and position of the uterus and ovaries. A speculum is also inserted into the vagina and the doctor or nurse looks at the vagina and cervix for signs of disease. A Pap test or Pap smear of the cervix is usually done. The doctor or nurse also inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
- Endocervical curettage: A procedure to collect cells or tissue from the cervical canal using a curette (spoon-shaped instrument). Tissue samples may be taken for biopsy. This procedure is sometimes done at the same time as a colposcopy.
Causes
All cancers are caused by dysfunctions of proteins involved in cell division, apoptosis, or DNA repair (see general characteristics). Dysfunctional proteins may arise from gene mutations or protein interaction with environments such as viral proteins. About 70% of cervical cancer patients are infected with HPV type 16 or 18. The genomes of HPV 16 and HPV 18 encode two proteins, E6 and E7, which can inactivate two crucial proteins involved in cell division: p53 and pRB (more info).
Reference:
National Cancer Institute, USA.
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