Cervical intraepithelial neoplasia is a precancerous condition in which abnormal cell growth occurs on the surface lining of the cervix or endocervical canal, the opening between the uterus and the vagina. It is also known as cervical dysplasia. Strongly connected with sexually transmitted human papillomavirus (HPV) infection, cervical intraepithelial neoplasia is most common in women under age 30 but can develop at any age.
Cervical intraepithelial neoplasia usually causes no symptoms, and is most often discovered by a routine Pap smear test. The outlook is positive for women with cervical intraepithelial neoplasia who receive appropriate follow-up and treatment. But women who go undiagnosed or who don't receive appropriate care are at higher risk of developing cervical cancer.
Mild cervical intraepithelial neoplasia sometimes resolves without treatment, and may only require careful observation with Pap tests every three or six months. But moderate to severe and mild cervical intraepithelial neoplasia that persists for two years normally requires treatment to remove the abnormal cells and reduce the risk of cervical cancer.
Causes of cervical intraepithelial neoplasia
In many women with cervical intraepithelial neoplasia, human papillomavirus is found in cervical cells. HPV infection is common in women and men, and most often affects sexually active women under age 20.
In most cases, the immune system eliminates HPV and clears the infection. But in some women, the infection persists and leads to cervical intraepithelial neoplasia.
Among women with a chronic HPV infection, smokers are twice as likely as non-smokers to develop severe cervical dysplasia, because smoking suppresses the immune system.
Chronic HPV infection and cervical intraepithelial neoplasia 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.
Risk factors for cervical intraepithelial neoplasia
Persistent HPV infection is the most important risk factor for cervical dysplasia, especially moderate to severe cervical intraepithelial neoplasia. In women, an increased risk of a persistent HPV infection is associated with:
Diagnosis of cervical intraepithelial neoplasia
- Early initiation of sexual activity
- Having more than one sex partner
- Having a partner who has had multiple sex partners
- Having sex with an uncircumcised man
Because a pelvic exam is usually normal in women with cervical intraepithelial neoplasia, a Pap test is necessary to diagnose the condition.
Although a Pap test alone can identify mild, moderate, or severe cervical intraepithelial neoplasia, further tests are often required to determine appropriate follow-up and treatment. These include:
- Repeat Pap tests
- Colposcopy, a magnified exam of the cervix to detect abnormal cells so that biopsies can be taken
- Endocervical curettage, a procedure to check for abnormal cells in the cervical canal
- Cone biopsy or loop electrosurgical excision procedure (LEEP) which is performed to rule out invasive cancer during a cone biopsy, the doctor removes a cone-shaped piece of tissue for lab examination. During LEEP, the doctor cuts out abnormal tissue with a thin, low-voltage electrified wire loop
- HPV DNA test, which can identify the HPV strains which are known to cause cervical cancer
The treatment for cervical intraepithelial neoplasia depends on many different factors, including the severity of the condition and the age of the patient. For mild cervical intraepithelial neoplasia, often only continued monitoring with repeat Pap tests is needed. For older women with mild cervical intraepithelial neoplasia, usually no treatment is needed unless mild cervical intraepithelial neoplasia has persisted for two years, progressed to moderate or severe cervical dysplasia, or there are other medical problems.
Treatments for cervical intraepithelial neoplasia include two of the procedures also used for diagnosis cone biopsy or LEEP. Other treatments include:
- Cryosurgery (freezing)
- Laser surgery
Because all forms of treatment are associated with risks such as heavy bleeding and possible complications affecting pregnancy, it's important for patients to discuss these risks with their doctor prior to treatment.