Cervical cancer diagnosis and screening
The traditional cervical smear test enables abnormal cells to be identified and treated before they develop into cervical cancer.
Cells from the surface of the cervix are collected and examined. Any abnormality found on a smear will be evaluated further.
In summer 2016, the NHS cervical screening programme in England announced that it is changing to testing for human papilloma virus (HPV) first rather than looking for cell changes in the cervix.
Most cases of cervical cancer are caused by persistent infection with HPV - so experts hope that identifying this risk earlier will lead to more accurate screening.
If HPV is found, a smear test will be performed to identify if abnormal cells are present. If they are present the cervix will be visually examined by colposcopy, and a tissue sample (biopsy) taken of any apparent abnormality for evaluation.
Colposcopy is a procedure similar to a pelvic examination. It can usually be done in the hospital out-patient department.
Colposcopy uses a type of microscope called a colposcope to inspect the cervix. The entire area of the cervix is stained with a harmless dye to make abnormal cells easier to see.
The colposcope magnifies the cervix by eight to 10 times, allowing easier identification of any tissue that appears abnormal and that may need biopsy. These abnormalities may be an early step in the series of changes that can gradually lead to cancer.
LLETZ, or Large Loop Excision of the Transformation Zone, involves cutting out the area of the cervix where the abnormal cells develop. LLETZ is simple and quick to carry out, and can be done under local anaesthetic.
A cone biopsy is a minor operation that you will have under a general anaesthetic. You will usually have an overnight stay in hospital. A small cone-shaped sample of your cervix is removed for examination. The cone includes the whole area of the cervical canal where there might be abnormal cells.
LLETZ and cone biopsy procedures produce tissue samples in which the types of cells and how much they have spread to underlying areas can be more fully determined.
Over the years, different terms have been used to refer to abnormal changes in the cells on the surface of the cervix. These changes are often called dyskaryosis or CIN (cervical intraepithelial neoplasia). "Dysplasia" refers to an area of abnormal tissue; intraepithelial means that the abnormal cells are present only in the surface layer of cells.
Changes in these cells can be divided into three categories.
- Mild dyskaryosis/CIN 1: One third of the thickness of the skin covering the cervix has abnormal cells. These lesions may go away on their own, but over time, they may become more abnormal, so it’s important to have them monitored.
- Moderate dyskaryosis/CIN 2: Two thirds of the thickness of the skin covering the cervix has abnormal cells. Treatment will be needed to remove the abnormal cells.
- Severe dyskaryosis/CIN 3: The full thickness of the skin covering the cervix has abnormal cells. Treatment will be needed to remove the abnormal cells.
Precancerous cells, even high-grade lesions, usually do not become cancerous and invade deeper layers of the cervix for many months, often years.
Ask your doctor if you do not understand the way the result of your cervical smear test is described.