This information provides a general overview on cervical screening and may not apply to everyone. Talk to your family doctor to find out if this applies to you and to get more information on this subject.
What is cervical screening?
There are 2 methods which are currently performed as part of cervical screening:
The cervical smear, commonly known as a PAP smear. This looks at cells which have been taken from the cervix (the opening of the uterus). They are examined under a microscope to see if they are normal. The PAP smear aims to detect early precancerous changes in the cervix which can be closely monitored or removed before any cancerous changes develop HPV testing. The cells from the cervix are tested for the presence of the HPV Virus. The majority of cervical cancers are known to have been caused by chronic HPV infection.
What is the HPV virus and how can I get infected?
The HPV virus is a very common virus and is spread by genital skin to skin contact during sexual activity. Prior to the development of the HPV vaccine, infection with HPV was so common that most people were infected at some stage of their lives and would never know as it is usually asymptomatic. There are many types of HPV virus and most people’s immune systems are able to clear the virus within 1-2 years of infection. However for some people, their body does not clear the virus and over time (10-15 years) chronic infection can trigger cellular changes that lead to cervical cancer. Luckily this only happens to a small minority of women who have chronic infection and it can be readily treated before cancerous changes develop.
What is the difference between the 2 types of test?
The 2 tests are performed in exactly the same way. The difference is in the test at the laboratory. The PAP smear gives an indication about whether the cells sampled have any precancerous changes present. If abnormal cells are found then these may be monitored closely or may need further treatment.
The HPV test identifies whether the cervix is currently infected with the HPV virus, and the subtype of HPV virus. We know that infection with certain subtypes of HPV virus is associated with an increased risk of developing pre-cancerous changes. So the HPV test is able to tell us which women are at higher risk of developing precancerous cells and need to be monitored more closely, and conversely which women are currently low risk and can safely have less frequent screening.
How is the test done?
Your family doctor will examine you. To do the cervical screening test an instrument, called a speculum is placed into your vagina. The speculum keeps the walls of the vagina apart so your doctor can see your cervix. A small brush is used to take some cells from the cervix. These are placed in a vial containing liquid and transported to the laboratory for testing. You may feel a light pressure, but it should not be painful. It is best to book your cervical screening in the middle of your menstrual cycle.
How often should I be tested?
Screening guidelines do vary between different countries but most authorities recommend a HPV testing every 5 years either alone or in combination with co-testing with a pap smear. If you choose to have a PAP test alone this should be performed every 2-3 years. Given the slow development of any changes of HPV or precancerous cellular changes this screening allows time for changes to be found before they have had time to develop into cancer.
Singapore guidelines call for cervical smears only for women younger than 30 years old and these are done every 3 years if they are normal. Women above 30 years old should have HPV testing every 5 years, if the test is normal.
More frequent testing would be necessary to follow up on abnormal smears.
Who should be tested?
- If you are between the age of 25-74, have a cervix and have ever been sexually active you should have cervical screening. This is irrespective of whether you are vaccinated for HPV.
- If you are under the age of 25 you do not need cervical screening. We know that HPV infection is very common in this age group but the majority will clear the infection with no further issues. Fortunately cervical cancer is very rare in this age group.
- If you are over 75 and have had normal cervical screening you do not need further testing.
- If you have had a hysterectomy with removal of the cervix and your previous cervical screening was normal you do not need further testing.
What happens if I have a positive HPV test?
If your HPV test is positive, this will be further categorised to show the HPV type. If it is found to be a high risk strain, you will be referred to a gynaecologist for further evaluation with a colposcopy. A colposcopy is a special examination of the cervix which uses a colposcope (which looks like a pair of binoculars mounted on a stand) and a vinegar-like solution to detect any abnormal cells. A small sample of tissue may be taken. A colposcopy feels like a normal pelvic exam but takes longer.
If you are found to have a low risk HPV type, the recommendation depends on your PAP smear result. If it is negative then the test will be repeated in 12 months time. If there are abnormal cells then you would be referred for a colposcopy.
Remember, HPV infection is very common and it does NOT indicate that you have cancer. The changes of cervical cancer take 10-15 years to develop and cervical cancer is still a rare outcome of HPV infection.
What happens if I have an abnormal PAP smear?
If the result is unsatisfactory then it means that not enough cells were taken from the cervix to be able to read the result. This needs to be repeated in 6-8 weeks.
If the cervix is inflamed or irritated then your PAP smear can be abnormal. In this case it is very useful to have a HPV test. If the inflammation is caused by HPV infection then you will need to have a colposcopy. If your HPV test is negative then you may be recalled for a repeat test in 12months to 3 years depending on the result. Often candida or yeast infection will cause these changes and may need treatment.
If your PAP smear shows signs of precancerous changes then you may be called for a repeat PAP or colposcopy depending on the result.
What can I do to reduce my risk of Cervical Cancer?
- Don’t smoke
- Reduce your risk of sexually transmitted infections
- Get vaccinated against HPV
- Have regular screening
What should I do if I have unusual symptoms but it isn’t time for my cervical screening test?
If you have any of the following symptoms you should see your doctor:
- Bleeding between periods
- Bleeding after intercourse
- Abnormal vaginal discharge
- Pelvic pain
- Swelling of the abdomen
- Abnormal bleeding while taking Hormone Replacement Therapy
- Any vaginal bleeding once you have gone through the menopause