What are cervical smear tests and why are they so important?

Cervical smear tests are very important in detecting precancerous abnormalities in the cervix. With early detection these can be dealt with accordingly, reducing the chances of cervical cancer developing. Mr Angus McIndoe is an award-winning obstetrician and gynaecologist and here he explains what a cervical smear test involves, what abnormal results mean and what follow-up tests might be performed.

What does a cervical smear test involve and how often should women be having them?

A cervical smear test involves a gentle internal examination to collect cells from around the cervix. We put these in a solution and then send them off to the lab where they can be processed to check for abnormal cells by the pathologist. It feels a bit strange when you first have an internal examination, feeling a little bit stretchy, but if it is done expertly and carefully, it should not be uncomfortable at all.

There is a new device available called a PapCone, which hurts a lot less than the traditional brush that is used throughout the UK. These are available at a small number of centres, including here at The McIndoe Centre.

In terms of frequency of smears, a lot of women have a smear test every year. It is widely suggested that every three years is enough, but sometimes that is a bit too infrequent. We know that smear tests are not terribly accurate and sometimes they can miss abnormalities. Hence, particularly if you haven't had many smears, it is not a bad idea to have a smear more frequently than every three years.

As for when women start having smear tests, I recommend starting screening at age 20 or sooner if you have been sexually active before this age. National guidelines state screening begins at age 25, but frighteningly, the peak incidence of cancer of the cervix is between 25 and 30 years of age.

National screening increased the first screening age from 20 to 25 about 15 years ago and since then we have seen a 50 per cent increase in women between the ages of 25 and 30 getting a cancer. If you think about it, that is an absolute disaster for these young women, because it may be possible to cure the cancer, but it affects their chances of having babies in the long-term.

There is a new test being introduced called an HPV test which will probably pick up a few more precancerous abnormalities than the smear test. This is a real hope for the future. The other thing that is a hope for the future is HPV vaccination; which has been rolled out to young girls across the country and seems to be reducing the incidence of cancer in the cervix quite dramatically.

What does an abnormal smear test result mean?

An abnormal smear test suggests that there are some cells in the skin of the cervix which are growing a bit faster than they should do. If left, these might become a cancer. We divide the abnormalities into low grade and high grade.

Low grade changes represent very minor abnormalities which most of the time will just go away by themselves and what we tend to do with low-grade abnormalities is just watch and wait with the expectation that the cervix will clear.

With high-grade abnormalities, these are ones that are much more likely to become a cancer over time and so these are the ones that we tend to treat. Treatment is relatively straightforward as we can just remove the area of skin that is abnormal. Afterwards, the smear test should return to normal.

If a woman presents with a low-grade abnormality, it is important that she then goes for a colposcopy, because about one in 10 women with a low-grade abnormality on their smear test will actually have a high-grade abnormality when we look with the colposcope. Examination with the colposcope is to identify those women that have an unexpected high-grade abnormality. By far and away the most likely finding is a low-grade change which as I said will go away by itself over one to two, or maybe three years.

Does an abnormal smear test result always indicate cancer?

An abnormal smear test usually does not indicate cancer. In fact, very rarely will an abnormal smear test result from cancer. The vast majority of abnormalities we see from the smear test are relatively minor changes in the skin of the cervix, which if left will go away by themselves. Occasionally, it is a slightly more serious abnormality, but these can still be removed quite simply. It is extremely rare that the smear test will actually show that you have a cancer.

What tests will follow an abnormal smear result?

If a woman has an abnormal smear test, she will be sent for colposcopy. This involves a careful examination of the cervix. It is a bit like a smear test but takes slightly longer. We use the same speculum as we do for a smear test, but with the colposcope, we put some solutions on the cervix which make it apparent whether any of the cells look abnormal.

Interestingly, with an abnormal smear test, the cervix looks completely normal to the naked eye. It is only when we put solutions on and use the magnification about 10 times with the colposcope that we can see these abnormalities.

Low grade abnormalities

What we are looking for is to try and decide whether the abnormalities are low-grade; in which case we tend to be very conservative and just watch and wait with the expectation that it will go back to normal by itself.

High grade abnormalities

If the abnormality is high-grade, then we will often take a biopsy from the cervix just to be absolutely sure what it is that we are treating. If we confirm that there is a high-grade abnormality, then the usual treatment is just to remove that with a wire loop or a needle to take away the bit of skin that is abnormal.

After that, for the vast majority of women, that is all that will be needed, just a single treatment. Very occasionally, women require a second treatment but that is not common. One of the tests that we use to help decide between low grade and high grade is an HPV test. With which we can look to see whether there are any high-risk HPV types which are associated with the most serious abnormalities. If the HPV test is negative then that can be very reassuring that there is nothing very serious going wrong with the cervix.

If you would like to find out more about cervical smear testing, make an appointment with an expert like Mr McIndoe.