In most cases, cancer of the cervix can be prevented by having regular smear tests. Additionally, the vaccination programme is helping to further reduce the incidence of cervical cancer. Even if a cancer of the cervix develops, it is usually detected early due to abnormal bleeding, and can be treated with an excellent chance of cure.
Cancer of the cervix develops from areas of precancerous cells called CIN. These are small areas on the skin of the cervix where the cells are dividing faster than usual. These areas cause no symptoms, but we know that if left, over a period of years, some may develop into cancers. CIN looks normal to the naked eye, but can be revealed with an examination called colposcopy, where the cervix is examined in detail using about 10 times magnification and a dilute vinegar solution. A colposcopy examination is usually painless, and is quite similar to having a smear test.
Low grade CIN is not usually treated in the UK as studies over the last few years have shown that most of these low grade changes will go away by themselves without any treatment. This usually takes two or three years but may be quicker.
During this time, it is common to keep the areas of CIN under close surveillance. If areas of high grade CIN are identified at colposcopy, these can be removed under either local or general anaesthetic using either a wire loop, sometimes called a LLETZ procedure, or with a laser. Usually only one treatment is needed, provided that the whole abnormal area is removed – although there is a very small chance that the abnormality will reoccur.
CIN and cervical cancer only develop in women who have human papillomavirus (HPV) infection. This virus has the ability to link in to the DNA of human cells and disrupt the normal control mechanisms of cell division. This may cause the cells to divide faster than normal, and can lead to the development of CIN. Most women who have HPV infection will never develop CIN, and their immune system will get rid of the virus without any treatment. However, in a small number of women the virus persists, which increases the chance of CIN developing. If CIN is undetected or untreated it may go on to become a cervical cancer.
HPV testing is now used as part of the national screening programme. Women who are negative for the HPV types that are associated with cervical cancer, the so-called “high-risk HPV types”, have a very low risk of developing CIN. Women who have high-risk HPV may develop CIN, although most will not. However, these women warrant slightly closer observation to ensure that CIN does not develop.
HPV vaccination is also offered to girls at the beginning of secondary school. These injections produce very high levels of antibody, which provide excellent protection against the HPV types in the vaccine. Unfortunately, the vaccine does not provide protection against all HPV types, but the two most common high-risk HPV types, HPV 16 and HPV 18, are included in the vaccine. Some degree of cross protection against other HPV types likely occurs, although we don’t know to what extent.
Most cases of cervical cancer occur in women who have not had recent cervical smears. In a small number of women, the smear test may have missed a small precancerous abnormality. The smear test on its own is between 85% and 95% reliable in detecting CIN so it is by no means perfect. However, as most of these abnormalities take many years to develop, more than one smear is usually taken and this helps to make up for it’s shortfalls.
Very early cancers are sometimes detected by a smear test, before symptoms develop. However, bleeding after sex or between periods, or a persistent discharge may suggest the presence of a cervical cancer. The best way to exclude a cervical cancer is with a colposcopy examination.
The treatment of many early cancers is an operation involving removal of the cervix and uterus (womb), the tissues around the cervix, and pelvic lymph nodes. In young women who have not yet had children, the uterus can sometimes be preserved to allow for pregnancy by an operation called a trachelectomy. Very small cervical cancers are sometimes treated by removing a small part of the cervix only.
Radiotherapy may be offered as an alternative to surgery. The cure rate for radiotherapy is the same as for surgery.
The chance of cure for cancer of the cervix depends upon the size of the cancer when it was diagnosed. Most cervical cancers are diagnosed at an early stage in the UK, particularly in women who attend for smears. In that case, the chance of cure is around 90%, depending on the size of the tumour. In women who present with larger cancers, the chance of cure may be reduced, but usually the prognosis is good. These tumours usually respond well both to radiotherapy and to surgery.
Mr McIndoe is an renowned expert on the comprehensive treatment of cervical cancer, and is confident that many cases are highly treatable through an expertly planned, multidisciplinary approach.