Tests Done at Colposcopy

There are two different techniques used to identify abnormal cell changes during the colposcopic examination:

  1. Acetic Acid Colposcopy

    Acetic acid (dilute vinegar) is applied to the cervix using a cotton wool ball or by a spray. Abnormal areas such as CIN will tend to turn white (acetowhite). It is important to say that some areas of acetowhite do not indicate CIN at all. One of the challenges facing the colposcopist is to decide which areas of acetowhite truly represent areas of abnormal cells that need to be removed so that over treatment is avoided.

  2. Schiller’s Iodine Test

    The colposcopist may use another test using an iodine solution. Normal tissue on the outside of the cervix stains dark brown when iodine is applied. On the other hand, cervical abnormalities may not stain with iodine. This test may be used following acetic acid colposcopy and is often used before treatment.

Diagnosis

Most colposcopists use a combination of the acetic acid and Schiller’s iodine tests. If there is an abnormality the colposcopist should be able to estimate whether or not treatment will be needed according to:

  • How white the tissue goes after using acetic acid
  • How quickly the tissue turns white
  • How smooth or irregular the surface is
  • The different patterns of the blood vessels (mosaic and punctation) under the surface of the cervix.

Taking a Biopsy

To be sure of the diagnosis, a biopsy is often required – this means taking a sample of tissue from the cervix. Depending on the results of this biopsy the colposcopist will decide whether you need treatment. There are 2 types of biopsy that could be offered. A diagnostic or punch biopsy is a small biopsy which often doesn’t require local analgesia and two or three of these may be taken at the first visit. The second is a loop excision which is slightly larger and does require local anaesthetic. This type of biopsy is usually a treatment biopsy and under certain circumstances can be performed at the first visit in some clinics.

If it is obvious that you will need treatment this can be done during the same visit – in this case all of the abnormal area is removed and this constitutes the biopsy. Other more invasive types of treatment require a separate appointment.

Treatment options will be outlined to you in your information leaflet before your clinic appointment and will be discussed with you in clinic. Sometimes taking the biopsy can be uncomfortable but the person performing the colposcopy will warn you before the biopsy is to be taken. Your colposcopy shouldn’t be painful and if you have any difficulty you should discuss this with the colposcopist. If necessary the colposcopy can be stopped.

Results of Biopsy

When your biopsy is analysed in the laboratory, they will be looking for different changes in the cells.
The changes they review are:

  • The cell nucleus – irregular size, shape and colour of the cell nucleus is the first indication of an abnormality.
  • The maturity of the cells – a normal cell will grow from an immature to mature cell. Cells that are abnormal can often still grow into mature cervical cells which still function in a similar way to normal cells. If the abnormal cells still mature this indicates a low grade abnormality (e.g. CIN 1). New cells that grow with increased abnormalities may no longer be able to function normally and may remain as immature abnormal cells. The more immature the abnormal cells there are the higher the grade of abnormality (e.g. CIN2 and 3). Immature abnormal cells have greater potential to develop into cancerous cells than mature abnormal cells.
  • The thickness of abnormal cells in the lining of the cervix – the grading for CIN cells comes from the thickness of immature abnormal cells within the ectocervix.

If your biopsy comes back positive it is because you have abnormal cells or cervical intraepithelial neoplasia (CIN), you will have both abnormal mature cells and variable quantities of immature abnormal cells. Abnormal cells may develop into cancer so the quantity of these cells within the ectocervix is important. The grading of CIN is established according to the amount of immature cells within the sample taken.
This means that:

  • If you have CIN 1 the lining of the cervix has fully normal cells at the surface and the lower 1/3 has immature abnormal cells.
  • CIN 2: the lining of the cervix has norrmal cells at the surface and the lower 2/3 has abnormal cells.
  • CIN 3: the lining of the cervix has abnormal cells throughout it’s entire thickness

All the results above mean that you have cervical abnormalities. This does not mean that you have or will get cancer. It just means that the laboratory has detected some changes to your cells that are abnormal and, if they are not treated, they may develop into cervical cancer in the future.

Abnormal Cervical Cells: CIN and CGIN

The cervix is covered with a layer of skin-like cells on its outer surface called the ectocervix. There are also glandular cells usually lining the inside of the cervix called the endocervix. These cells produce mucus. The skin-like cells of the ectocervix can become cancerous, leading to a squamous cell cervical cancer. The glandular cells of the endocervix can also become cancerous, leading to an adenocarcinoma of the cervix. Changes to these different areas are categorised differently: Cervical Intraepithelial Neoplasia (CIN) are cellular changes to the ectocervix and Glandular Cervical Intraepithelial Neoplasia (CGIN) represent abnormal changes to the endocervix.

Treatment for CIN depends on the degree of abnormality of the cells. CGIN is not as common as CIN, but it is treated similarly. There is no good evidence that CGIN is “more aggressive” than CIN. CGIN is harder to pick up during screening and since the cellular changes are inside the cervical canal they can be marginally more difficult to treat.

If your cervical screening result shows abnormal cells you may be asked to attend a colposcopy appointment. Remember testing positive for CIN or CGIN means that you have abnormal cervical cells that may, if untreated lead to cancer but CIN and CGIN are not in themselves cancerous. Treatment for abnormal cellular changes is usually very successful.

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