The Pap smear – also called ’smear test’ or ‘Papanicolaou smear’ (after its inventor) – is a simple test in which some cells are wiped from the surface of the cervix and examined under the microscope. The test was first used in the 1920s to diagnose cancer of the cervix. It was soon clear that the smear could also show certain changes in cells that might precede the development of cancer. This led to the use of the smear as a screening test, so that women who might be at risk of later developing cervical cancer could be identified and treated, if necessary, to prevent it. It is thought that among women who are screened, 90 per cent of cervical cancers can be prevented. In countries where regular screening is encouraged, the death rate from cancer of the cervix is decreasing.
We don’t know what causes cervical cancer, but there seems to be an association with sexual behaviour. It is rare among women who have never had sex, and occurs most often in women who began intercourse at an early age and/or have had a number of sexual partners. But we are all potentially at risk, so smears are advised for all women from the age of 18 (or within two years of first sex, whichever] is later) until 70 years of age.
How is a Pap smear done?
Very easily. A speculum is inserted into the vagina to hold its walls apart so that the cervix can be seen. A specially shaped wooden or plastic spatula or a small brush is then wiped around the cervix. This doesn’t hurt: some women feel an unusual sensation while the smear is being taken, but many feel nothing. The cells collected are transferred to a glass slide, which is sprayed with or dipped in a solution to preserve the specimen. It takes about two minutes to prepare for and collect the smear, though it is usually done as part of a general gynaecological check, which takes longer.
How often should it be done?
If the first smear is normal, repeats are advised every two years. If any suspicious changes are found at any time, more frequent smears are advised until the abnormality disappears, with or without treatment.
In Australia about 1000 women develop cancer of the cervix each year and 350 die from it. These figures haven’t changed in lie past 10 years. Why should this be so, when we are spending more than $60 million per year on Pap screening? The answer is that young women, who are at lowest risk, are being screened regularly, while women over the age of 50 (among whom the risk is highest) are either not screened at all or have very infrequent smears.
In 1991 the National Policy on Cervical tar Prevention was launched. The aim of the policy is to reduce the number of cervical cancer cases and deaths by keeping a register of all Paps done, by encouraging women who have never been screened to begin regular tests, by reminding women when their next smear is due, and by making sure that all abnormal results are properly followed up and treated if necessary. A quality assurance committee has also been set up to monitor Pap smears and ensure that samples and smears examined to give the most reliable results.
What if your Pap smear is abnormal?
You will probably be very distressed, thinking that it means you have cancer. This is almost never the case. What it usually means is that a change has been seen that might progress to cancer some years down the track. You will be advised to have more frequent smears and perhaps some other examinations. The majority of these changes disappear. If there’s any sign of progress towards cancer, you can have treatment to prevent it from developing.
Around five out of every hundred smears show some abnormality. Most of these are minor changes. Less than one in a hundred shows more serious changes suggesting progress towards cancer, and of these less than half are likely to become cancerous and will take an average of seven years to do so. Thus there is plenty of time for preventive treatment, which is always advised in these cases as we have no way of predicting which ones will progress. Around one in a thousand are suspicious for early cancer. Established invasive cancer is found very rarely.
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