Precancerous conditions of the cervix

Precancerous conditions have the potential to develop into cancer. With a precancerous condition, abnormal changes have taken place in the cells of the cervix. Over time, some of these precancerous changes can turn into cancer if left untreated. It may take many years (typically about 10 years or more) for precancerous conditions to progress into an invasive cervical cancer, but sometimes this can happen in less time.


The most common precancerous conditions of the cervix are:

  • cervical dysplasia
  • cervical intraepithelial neoplasia (CIN)
  • squamous intraepithelial lesion (SIL)
  • atypical glandular cells


All these conditions include precancerous changes to the cells that are found in the surface layer of the cervix. Precancerous changes in the cervix are quite common. They occur most often in women in their 20s and 30s.


There are a few different ways to describe precancerous conditions in the cervix depending on how abnormal the cells look under the microscope and how severe the cell changes are.


Precancerous changes in the cervix – cervical dysplasia, CIN and SIL

Cervical dysplasia

Cervical intraepithelial neoplasia (CIN)

Squamous intraepithelial lesion (SIL)




low grade

early changes to the cells


considered a mild abnormality


marked changes to the size and shape of the cells


cells considered abnormal


associated with a higher risk of becoming cancer or may indicate that there is an underlying cancer


CIN III also includes carcinoma in situ


Precancerous changes in the cervix – atypical glandular cells

Glandular cell abnormalities (Bethesda system)

Also includes


atypical glandular cells (AGC)

endocervical dysplasia


atypical hyperplasia


endocervical glandular atypia


cervical intraepithelial glandular neoplasia (CIGN) grade 1 or 2

Cells do not appear normal.


Changes are associated with a higher risk of becoming cancer or may indicate that there is an underlying cancer.

adenocarcinoma in situ (AIS)

endocervical AIS


CIGN grade 3

Cancer cells are found in the glandular tissue of the cervix (endocervix) but have not spread into the deeper tissues of the cervix or surrounding tissue (non-invasive or pre-invasive).



Risk factors

The following risk factors may increase a woman's chance of developing a precancerous condition of the cervix.

  • persistent human papillomavirus (HPV) infections
  • having many sexual partners
  • becoming sexually active at a young age
  • smoking
  • weakened immune system
  • multiple pregnancies (multiparity)
  • long-term oral contraceptive use
  • lower socio-economic status

Signs and symptoms

Precancerous changes in the cervix often do not cause any signs or symptoms.


An abnormal Pap test result is often the first sign that some cells in the cervix are abnormal. This is why it is important to have regular Pap tests and pelvic examinations.


If the doctor suspects a precancerous condition of the cervix, further tests will be done to make a diagnosis. Tests may include:

  • another Pap test after a few months (usually 3 to 6 months), if there are mild changes
  • HPV test, which may be done on a sample of cervical cells taken during a Pap test
  • colposcopy and biopsy
  • endocervical curettage during colposcopy


Often, milder changes (such as CIN I or low-grade SIL) return to normal without any treatment. The doctor will discuss if repeating the Pap test later on and waiting to see if mild changes will resolve on their own is an option. More severe abnormalities (such as CIN III or high-grade SIL) are more likely to develop into invasive cervical cancer, especially if they are not treated. It is hard to predict which of these will become invasive and which will not.


Treatment options for precancerous changes in the cervix may include:


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We can give information about cancer care and support services in Canada only. To find a cancer organization in your country, visit Union for International Cancer Control or International Cancer Information Service Group.