Screening for Cervical Cancer

Screening for cervical cancer by examining cells sampled from the cervix was introduced in the UK in 1964. No significant benefit was seen until the introduction of computerised call and recall of women for cervical screening in 1988. Since then around 80% of the eligible population have been screened regularly and the death rate from cervical cancer has fallen from 8.2 per 100,000 women in 1971 to 2.4 per 100,000 women in 2008.

Due to the slow progression of this disease it is feasible to identify potential cancers of the cervix in the pre-cancerous phase and to carry out interventions to prevent the development of invasive cancer. 

The cervical screening programme

Women are invited for their first screening test at the age of 25. Screening is carried out at three year intervals between the ages of 25 and 50, and at three to five year intervals between 50 and 65. Screening ceases after the age of 65 if the woman has had three negative screens in the recent past and is not on a follow-up schedule for a previous abnormality.

An abnormal cervical smear result may require a referral for further assessment to a colposcopy clinic. A colposcope is a magnifying instrument designed to examine the cervix. The aim of colposcopy is to diagnose low or high grade dysplasia (abnormal epithelial cell growth) and manage these changes accordingly. There is close liaison between cytologists, colposcopists and pathologists so that patients get the best possible advice about their abnormal smears.

Treatment of abnormal smears

The aim of the initial assessment with cytology, colposcopy and pathology is to diagnose low or high-grade disease. If a woman has low-grade changes then she may be managed expectantly with follow-up smears and colposcopy as up to 80% of low-grade changes resolve without treatment.

High-grade disease is usually treated by excision biopsy as the risk of progression to invasive cancer is significant. The abnormal area is removed usually by a procedure known as loop diathermy. After identification of the abnormal area by colposcopy, a local anaesthetic injection is administered into the cervix and a heated wire loop is passed through the cervix to remove the abnormal area. The wire is heated with an electric current (diathermy) so that the procedure is performed precisely and rapidly with no pain to the patient. The cut surface of the cervix is then sealed with a small metal ball heated with a different type of electric current, which helps control the bleeding. The procedure should take no more than 15 minutes and the patient should be fully informed of the nature of the procedure and potential complications before the procedure takes place.

The excised specimen is then sent for pathological analysis to confirm the diagnosis and exclude invasive cancer. An initial follow-up smear is performed 6 months after the procedure and then annually from the date of the procedure for 10 years. 

Complications of loop diathermy surgery

Major complications after this procedure are very rare. The commonest early complication is infection, which causes heavy bleeding or an offensive discharge. This may be treated with antibiotics but occasionally heavy bleeding may require a vaginal pack or a suture to the cervix.

Later complications are very uncommon but it is recognised that two or more loop diathermy treatments lead to weakening of the cervix and predisposes to late miscarriage and premature delivery in a subsequent pregnancy. Women in this situation may be advised to have a supporting suture inserted into the cervix at around 14 weeks of pregnancy. It was believed that one treatment carried virtually no risk of this complication, but recent research does suggest that there is a risk that women should be made aware of.