Screening for precancerous changes on the cervix is a very important aspect of preventative health care and in the past women have been advised to have a regular Pap smear every 2 years. The Pap smear is able to detect abnormalities in the cells of the cervix, which when treated can prevent the development of cancer of the cervix. The vast majority of cervical cancers are caused by the oncogenic strains of Human Papilloma Virus (HPV) specifically HPV types 16 and 18. There are over 100 types of HPV and types 6 and 11 are associated with genital warts. The HPV infection is acquired as a sexually transmitted infection and is thought to affect more than 50% of the population. A major advance in health care has been the introduction of a vaccine to protect against the HPV virus and this is now administered to both girls and boys in secondary school at 15 years of age. The Gardasil vaccine is a recombinant human papilloma virus vaccine that protects against HPV types 6, 11, 16 and 18 protecting against the oncogenic viruses (16,18) and genital warts (6,11). As a result of this vaccination program it is expected that 90% of cervical cancers which are HPV related will be eliminated from the population. This has prompted the government to change the previous cervical screening program with the introduction in December 2017 of the new National Cervical Screening Program. This applies particularly to women who have had the Gardasil vaccine with cervical screening for HPV commencing at 25 years of age which tests specifically for HPV 16, 18, 6, and 11. In those screening negative for these HPV types because they have been previously vaccinated, no further testing is recommended for 5 years ! If the HPV test returns a positive result, the cervical smear is prepared and assessed by the Thin Prep method and the patient is referred for colposcopy if an abnormality is detected. For women who have not received the Gardasil vaccine, the Cervical Screening test for HPV can also be done to detect the presence of high-risk HPV with management carried out according to the findings on testing. This screening protocol of HPV testing should cease at 50 years of age when the conventional Pap smear should be performed every 2 years to detect abnormalities of the cervix and uterus which are not HPV related with this testing continuing until 70 years of age. The Cervical Screening Test is performed on patients with no symptoms. If you have abnormal bleeding, pain or vaginal discharge you should see your doctor who will perform an examination and take a conventional Pap smear with possible referral for further investigations.
For 9 in 10 women, a normal cervical smear will tell their doctor that everything is normal, however, 1 in 10 women may have a positive or abnormal smear. Having a positive smear means that there may be abnormal or precancerous tissue on the cervix which will require further investigation. There are other conditions such as inflammation or vaginal infection or HPV infection which will cause the Pap smear to be reported as abnormal. Vaginal infections with either bacteria or fungi may cause an abnormal Pap smear. Treatment of these infections is important as it will ensure that a proper evaluation of the cervix can be made and the repeat smear will return a normal result. An abnormal smear may also be due to HPV infection which may revert to normal in a small number of patients as the immune system overcomes the virus.
When the cervical smear is ‘abnormal’ it will be reported as showing either low grade changes (LGSIL) or high grade changes (HGSIL). In this situation you will be referred for a special examination called a colposcopy whereby the cervix is inspected with a special instrument called a colposcope. The patient is placed in stirrups and a speculum is inserted into the vagina to display the cervix. The colposcope allows magnification of the cervix and after application of acetic acid (vinegar), the exact nature of the underlying abnormality can be established. If a lesion is found to be present on colposcopy, a biopsy is taken to confirm the diagnosis. This examination is done in the rooms while you are awake and takes no more than 15 minutes. Throughout the examination the doctor will explain what is going on and afterwards will discuss the findings and advise on the treatment options. If minor changes only are seen, you may be told that treatment is not necessary but you will require a repeat Pap smear within a certain period of time. If an abnormality (dysplasia) is confirmed on biopsy, arrangements will be made for treatment to remove the abnormal tissue from the cervix.
The terms dysplasia or cervical intraepithelial neoplasia (CIN), are the words used to describe the precancerous tissue that has developed on the surface of the cervix. There are three grades of dysplasia from mild to severe:
CIN 1 = mild dysplasia
CIN 2 = moderate dysplasia
CIN 3 = severe dysplasia
When the Pap smear is reported as LGSIL it refers to CIN 1 and HPV, whereas HGSIL refers to CIN 2 and CIN 3 as the probable precancerous lesion on the cervix. It must be remembered that the Pap smear is only a screening test and is not a diagnosis of the underlying lesion on the cervix: this can only be established by colposcopy and biopsy.
Once a precancerous lesion has been confirmed on the cervix, it can be treated to prevent its progression to cancer. The aim of any treatment will be to destroy or remove the abnormal or dysplastic tissue on the cervix and this is often done by electrocoagulation loop excision or diathermy. Under certain circumstances a cone biopsy may be required for both diagnostic and therapeutic purposes. Both these procedures are done under a general anaesthetic.
After your treatment you will need to return 3 months, 6 months and 12 months later for follow up smears to ensure complete eradication of the abnormal tissue from the cervix. Thereafter, Pap smears are taken every 12 months until 70 years of age.