Colposcopy
Colposcopy is a diagnostic procedure to examine an illuminated, magnified view of the cervix and the tissues of the vagina. A colposcopic examination follows an abnormal cervical smear report.
ABNORMAL CERVICAL SMEAR
An abnormal smear report may be described as
Borderline nuclear changes
Low grade changes (mild dyskaryosis)
High grade changes (moderate and severe dyskaryosis)
An abnormal smear report indicates that there are precancerous changes in the cells covering the cervix. High grade changes comprising of moderate and severe dyskaryosis are referred urgently for colposcopic assessment.
Many premalignant and malignant lesions on the cervix have detectable characteristics which can be identified through the colposcope, and biopsies are taken for examination of the affected tissues.
COLPOSCOPY
Colposcopy is an outpatient procedure performed with the woman lying on her back in lithotomy position. A speculum is inserted to open the vagina to visualise the cervix. The colposcope is a microscope placed outside the speculum (and outside the body) which magnifies the image of the cervix. Special dyes are used to paint the cervix to demonstrate any abnormal appearing areas. The dyes commonly used are 3-5% acetic acid and iodine. It is very important to visualise an area on the cervix called the transformation zone where most of precancerous and cancerous lesions arise.
Areas of the cervix which turn white after the application of acetic acid or have an abnormal vascular pattern are abnormal, and application of iodine helps in highlighting these areas as they do not take the dark brown stain of the iodine. Colposcopic assessment classifies the lesion as low grade and high grade.
After a complete examination, the areas with the highest degree of visible abnormality are defined and biopsies obtained. Most doctors and patients consider anesthesia unnecessary, however, a local anaesthetic may be used to diminish patient discomfort, particularly if more than one biopsy samples are taken. The raw areas after biopsy are cauterised with silver nitrate to control bleeding. Women can expect to have a thin grey discharge for up to several days after the procedure.
BIOPSY RESULTS
Abnormalities on the biopsy samples are then described as:
CIN 1 – one third of the thickness of the lining covering the cervix has abnormal cells
CIN 2 – two thirds of the thickness of the lining covering the cervix has abnormal cells
CIN 3 – the full thickness of the lining covering the cervix has abnormal cells
Invasive cancer- where the abnormal cells have breached the basement membrane
TREATMENT
Without proper treatment, precancerous abnormalities may develop into cancerous lesions. Various treatments exist for significant lesions, the most common being large loop excision of transformation zone (LLETZ). All treatment procedures aim to remove or destroy the abnormal cells.
LLETZ (Large Loop Excision of Transformation Zone) is an outpatient procedure and the patient can go home immediately after the procedure. It involves removing the abnormal cells on the cervix using a thin metal loop through which an electric current is passed- an electrosurgical technique. The procedure is done under local anaesthesia under colposcopic guidance. However for very anxious women or where the procedure is expected to be difficult, the procedure can be done in operating theatres under general anaesthesia.