About cervical dysplasia
What is cervical dysplasia?
Cervical dysplasia refers to the presence of precancerous changes of the cells that make up the surface of the cervix, the opening to the womb (uterus). The term dysplasia refers to the abnormal appearance of the cells when viewed under the microscope. The degree and extent of abnormality seen on a tissue sample biopsy was formerly referred to as mild, moderate, or severe dysplasia. In recent years, this nomenclature has been replaced by a newer system. These systems are based upon changes in the appearance of cells visualized when smears of individual cells (cytological changes) or tissue biopsies (histological changes) are reviewed under a microscope. Pap smears obtain samples of the surface cells to determine if they are normal or abnormal and do not provide a diagnosis, which can only be done by a tissue biopsy.
- Pap smears are described according to the degree of abnormality: ASCUS (atypical squamous cells of uncertain significance), LSIL (low grade squamous intraepithelial lesion) and HSIL (high grade squamous intraepithelial lesion. Cells from glandular rather than squamous epithelium may also be described.
- Cervical intraepithelial neoplasia (CIN) is cervical dysplasia that is a pathological diagnosis based on a cervical biopsy or surgically removed cervix. This is indicated by CIN1 (mild), CIN2 (moderate), CIN III (severe). These are all precancerous conditions.
These classification systems will be further discussed below.
Are there signs and symptoms of cervical dysplasia?
Typically, cervical dysplasia does not produce any signs or symptoms. So regular Pap smear screening is important for early diagnosis and treatment.
How is cervical dysplasia diagnosed?
Screening for cervical dysplasia
Cervical dysplasia and cervical cancer generally develop over a period of years, so regular screening is essential to detect and treat early precancerous changes and prevent cervical cancer. Traditionally, the Papanicolaou test (Pap test or Pap smear) has been the screening method of choice. To perform the Pap smear, the health care practitioner removes a swab or brush sample of cells from the outside of the cervix during a pelvic examination using a speculum in the vagina for visualization. The cells are smeared onto a glass slide, stained, and observed under the microscope for any evidence of abnormal cells.
Newer, liquid-based systems to screen samples of cervical cells are now much more common and are effective screening tools for detection of abnormal cells. The samples for this test are obtained the same way as for the conventional Pap smear, but the sample is placed in a vial of liquid that is later used to prepare a microscope slide for examination as with the Pap smear.
For women whose initial screening result is unclear or abnormal, other diagnostic tests are used:
- Colposcopy is a gynecological procedure that illuminates and magnifies the vulva, vaginal walls, and uterine cervix in order to detect and examine abnormalities of these structures. A colposcope is a microscope that resembles a pair of binoculars. The instrument has a range of magnification lenses. It also has color filters that allow the physician to detect surface abnormalities of the cervix, vagina and vulva.
- A Biopsy is a tissue sample obtained for examination under the microscope. A biopsy is taken from suspicious surface areas seen during colposcopy. A diagnosis can only be made from a tissue biopsy.
- HPV testing to detect a "high-risk" type is done if a Pap smear is abnormal or may be recommended for some women. Use of HPV testing alone is being suggested as a replacement for the Pap smear.
How is cervical dysplasia classified?
Cytologic analysis (screening tests)
Pap smear reports are based on a medical terminology system called The Bethesda System that was developed at the National Institutes of Health (NIH) in Bethesda, Maryland in 1988 and modified in 2001. The major categories for abnormal Pap smears reported in the Bethesda Systems are as follows:
- ASC-US: This abbreviation stands for atypical squamous cells of undetermined significance. The word "squamous" describes the thin, flat cells that lie on the surface of the cervix. One of two choices are added at the end of ASC: ASC-US, which means undetermined significance, or ASC-H, which means cannot exclude HSIL (see below).
- LSIL: This abbreviation stands for low-grade squamous intraepithelial lesion. This means changes characteristic of mild dysplasia are observed in the cervical cells.
- HSIL: This abbreviation stands for high-grade squamous intraepithelial lesion. And refers to the fact that cells with a severe degree of dysplasia are seen.
Histologic analysis (cervical biopsies)
When precancerous changes are seen in tissue biopsies of the cervix, the term cervical intraepithelial neoplasia (CIN) is used. "Intraepithelial" refers to the fact that the abnormal cells are present within the lining, or epithelial, tissue of the cervix. "Neoplasia" refers to the abnormal growth of cells.
CIN is classified according to the extent to which the abnormal, or dysplastic, cells are seen in the cervical lining tissue:
- CIN 1 refers to the presence of dysplasia confined to the basal third of the cervical lining, or epithelium (formerly called mild dysplasia). This is considered to be a low-grade lesion.
- CIN 2 is considered to be a high-grade lesion. It refers to dysplastic cellular changes confined to the basal two-thirds of the lining tissue (formerly called moderate dysplasia).
- CIN 3 is also a high grade lesion. It refers to precancerous changes in the cells encompassing greater than two-thirds of the cervical lining thickness, including full-thickness lesions that were formerly referred to as severe dysplasia and carcinoma in situ.
What are the symptoms for cervical dysplasia?
If you have cervical dysplasia, you may not experience any symptoms at all.
However, some people with cervical dysplasia that has progressed to cervical cancer may notice symptoms including:
- bleeding during or after sexual intercourse
- persistent vaginal discharge
- vaginal irritation
Because there are often no outward symptoms of cervical dysplasia, it’s important to get regular screenings for cervical cancer and dysplasia. This is part of a routine Pap smear. These tests are able to find cell changes that are invisible to the naked eye.
What are the causes for cervical dysplasia?
In many women with cervical dysplasia, HPV is found in cervical cells. HPV infection is common in women and men, and most often affects sexually active women under age 30.
In most cases, the immune system eliminates HPV and clears the infection. But in some women, the infection persists and leads to cervical dysplasia. Of the more than 100 different strains of HPV, more than one-third of them can be sexually transmitted, and two particular types -- HPV 16 and HPV 18 -- are strongly associated with cervical cancer.
HPV is usually passed from person to person during sexual contact such as vaginal intercourse, anal intercourse, or oral sex. But it also can be transmitted by any skin-to-skin contact with an infected person. Once established, the virus is capable of spreading from one part of the body to another, including the cervix.
Among women with a chronic HPV infection, smokers are twice as likely as nonsmokers to develop severe cervical dysplasia, because smoking suppresses the immune system.
Chronic HPV infection and cervical dysplasia are also associated with other factors that weaken the immune system, such as treatment with immunosuppressive drugs for certain diseases or after an organ transplant, or infection with HIV, the virus that causes AIDS.
What are the treatments for cervical dysplasia?
(These treatments are for CIN precancerous conditions only and are not appropriate for invasive cancer conditions.)
Most women with low grade (mild) dysplasia (CIN1 when the diagnosis is confirmed and all abnormal areas have been visualized), will frequently undergo spontaneous regression of the mild dysplasia without treatment. In others, it will persist, and in some, it will progress. Therefore, monitoring without specific treatment is often indicated in this group. Treatment is appropriate for women diagnosed with high-grade cervical dysplasia (CIN II and CIN III).
Treatments for cervical dysplasia fall into two general categories: destruction (ablation) of the abnormal area and removal (resection). Both types of treatment are equally effective.
The destruction (ablation) procedures are carbon dioxide laser, electrocautery, and cryotherapy. The removal (resection) procedures are loop electrosurgical excision procedure (LEEP), cold knife conization, and hysterectomy. Treatment is not done at the time of the initial colposcopy, since the treatment depends on the subsequent diagnosis of the biopsies obtained.
Carbon dioxide laser photoablation
This procedure, which is also known as CO2 laser, uses an invisible beam of coherent light to vaporize the abnormal area. A local anesthetic may be given to numb the area prior to the laser treatment. A clear vaginal discharge and spotting of blood may occur for a few weeks after the procedure. The complication rate of this procedure is very low. The most common complications are narrowing (stenosis) of the cervical opening and delayed bleeding. This treatment destroys the abnormal area.
Like the laser treatment, cryotherapy is an ablation therapy. It uses nitrous oxide to freeze the abnormal area. This technique, however, is not optimal for large areas or areas where abnormalities are already advanced or severe. After the procedure, women may experience a significant watery vaginal discharge for several weeks. As with laser ablation, significant complications of this procedure are rare. They include narrowing (stenosis) of the cervix and delayed bleeding. Cryotherapy also destroys the abnormal area and is generally felt to be inappropriate for women with advanced cervical disease.
Loop electrosurgical excision procedure (LEEP)
Loop electrosurgical excision procedure, also known as LEEP, is an inexpensive, simple technique that uses a radio-frequency current to remove abnormal areas. It is similar, but less extensive than a cone biopsy. It has an advantage over the destructive techniques in that an intact tissue sample for analysis can be obtained for pathologic study. Vaginal discharge and spotting may occur after this procedure. Complications rarely occur in women undergoing LEEP, and include cervical narrowing (stenosis) that may interfere with fertility and potentiall cause premature labor in a subsequent pregnancy.
Cold knife cone biopsy (conization)
Cone biopsy (conization) was once the primary procedure used to treat cervical dysplasia, but the other methods have now replaced it for this purpose. However, when a physician cannot view the entire area that needs to be seen during colposcopy, a cone biopsy is typically recommended. It is also recommended if additional tissue sampling is needed to obtain more information regarding the diagnosis. This technique allows the size and shape of the sample to be tailored to the condition. Cone biopsy has a slightly higher risk of cervical complications than the other treatments, which can include postoperative bleeding and cervical narrowing (stenosis) that may interfere with fertility and also premature labor.
What are the risk factors for cervical dysplasia?
Persistent HPV infection is the most important risk factor for cervical dysplasia, especially moderate-to-severe cervical dysplasia.
In women, an increased risk of a persistent HPV infection is associated with:
- Early initiation of sexual activity
- Having multiple sex partners
- Having a partner who has had multiple sex partners
- Having sex with an uncircumcised man