Cervical Intraepithelial Neoplasia (CIN)

Changes in the surface cells of the cervix that may become cancerous

  • Most common between the ages of 25 and 35
  • Unprotected sex at an early age, unprotected sex with multiple partners, and smoking are risk factors
  • Genetics is not a significant factor

In some women, the cells of the cervix gradually change from normal to cancerous. The condition between these two extremes, when the cells are abnormal and have the potential to become cancerous, is known as cervical intraepithelial neoplasia, or CIN (also sometimes called cervical dysplasia). There are three grades of CIN, depending on the severity of the changes in the abnormal cells: mild (CIN1), moderate (CIN2), and severe (CIN3). Mild CIN usually returns to a normal state by itself but moderate or severe CIN may progress to cancer of the cervix if not treated.

Many developed countries, including the UK, have established screening programmes that check for CIN using the cervical smear test. Regular testing to detect abnormal cells on the cervix helps to ensure that CIN is diagnosed and treated before abnormal cells become cancerous (it has been estimated that it takes an average of about 13 years for cancer to develop).

Cervical intraepithelial neoplasia (CIN)

These highly magnified images of cells taken from the cervix illustrate the degree of cell distortion that is present in mild and severe CIN.

What are the causes?

The exact cause of CIN is not known, but a number of different risk factors have been identified. For example, the risk of developing CIN appears to be slightly higher after exposure to some types of human papillomavirus (HPV). Other risk factors for the development of CIN include unprotected sex at an early age and unprotected sex with many partners because these activities are associated with an increased risk of acquiring HPV infection. Smoking also increases the risk of developing CIN.

How is it diagnosed?

CIN does not produce symptoms. Normally, the condition is only diagnosed after a cervical smear test, during which a sample of cells is taken from the cervix and sent for microscopic examination. If you are found to have abnormal cells, your doctor may arrange for you to have a colposcopy, in which the cervix is viewed through a magnifying instrument to examine abnormal-looking areas. A small sample of tissue may be removed from the cervix for examination under the microscope.

What is the treatment?

If you are diagnosed with CIN, the treatment depends on the degree of abnormality of the cells. Mild CIN may not require treatment because the abnormal cells revert to normal in most cases. However, the disorder will be regularly monitored with smear tests every 6 months. If CIN persists or worsens, treatment to destroy or remove the abnormal cells will be needed (see Treating CIN). The main methods of treatment are LLETZ (large loop excision of the transformation zone) and cone biopsy. After treatment, your condition will be monitored for the next few years to ensure that no further abnormalities develop.

Test and Treatment: Colposcopy

Treatment: Treating CIN

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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