Cervical cancer: Screening and prevention
Regular screening can prevent cervical cancer. But it can also lead to unnecessary treatments to remove abnormal tissue (dysplasia).
Cervical cancer (medical term: cervical carcinoma) develops when cells at the opening of the cervix change and become abnormal. Abnormal tissue can be discovered through screening and then removed before it has a chance to possibly develop into cancer. So this type of screening can also be seen as a form of prevention. Since it was introduced in the 1970s, there has been a big drop in the number of women with cervical cancer.
For this reason, statutory health insurers in Germany cover the costs of regular cervical screening in women aged 20 and over. The screening consists of a Pap test (smear test) to look for abnormal cells and a test for human papillomaviruses (HPV), which are considered to be the main cause of cervical cancer. Research has shown that HPV tests are also suitable for cervical cancer screening.
Women between the ages of 20 and 34 can have a free Pap test done once a year. From the age of 35, women are offered a combined test that includes a smear test and a test for certain human papillomaviruses (an HPV test) every three years.
How are Pap tests done?
In Pap tests, the doctor inserts an instrument (speculum) into the vagina and scrapes off mucous membrane cells using a small spatula or brush. The cells are taken from the part of the cervix that protrudes into the vagina, as well as from the opening of the cervix. This takes a few seconds and usually doesn’t hurt.
The samples of cells are sent to a lab, where they are examined under a microscope to find out whether there are any abnormal cells and – if so – how much they have changed. The results usually come back within a week.
What are the possible outcomes of Pap tests?
Most women’s Pap test results are normal. All they have to do is go back and have another Pap test a year later. And most “abnormal” results turn out to be caused by something that is harmless or easy to treat – not by cancer. The following table describes what the different Pap test results mean.
|Result||What it means|
|Pap I||The cells are healthy: Everything is okay.|
|Pap II||The cells have changed a bit, but this is generally not a cause for concern. Further tests or examinations aren’t usually needed.|
|Pap III||The cells have changed a lot or are very inflamed. But it isn’t possible to tell whether the changes in the cells are harmless or not. The Pap test may be repeated, or an HPV test may be done. The doctor may also look at the cervix using a kind of magnifying glass known as a colposcope. They can take a tissue sample (biopsy) at the same time. The tissue sample is sent to a lab, where it is examined to find out how much the cells have changed.|
|Pap IIID||The cell changes are minor or moderate, but not cancer. After six months, another Pap test is done, or an HPV test is done. Sometimes the cervix is also examined using a colposcope (colposcopy) and a biopsy is taken.|
|Pap IV||The cells are thought to have changed so much that they are likely to develop into cancer (CIN 3). Colposcopy and biopsy can be used to find out whether the abnormal tissue is already a tumor.|
|Pap V||This Pap test result means that tumor cells were found, and the tumor has probably already grown into deeper layers of tissue, a condition called “invasive carcinoma.” The doctor will have to take a tissue sample with the help of a colposcope to be sure.|
If abnormal cells are found, the treatment options will depend on how much the cells have changed. Mild and moderate cell changes (dyplasia) are usually just monitored. Cells that have changed a lot often develop into cancer, so doctors recommend surgery to remove them.
The HPV test
The HPV test is used to find out whether the cervix is infected with human papillomaviruses (HPV) that can cause cervical cancer. But it can’t predict whether the infection will clear up on its own or become a long-term infection. The type of virus can be determined using the test:
- Women who are infected with a high-risk type of HPV have a higher risk of cervical cancer.
- If the test doesn’t find any HPV (a negative HPV test), and the Pap test results are normal, the woman didn’t have a higher risk of getting cervical cancer at the time the test was done.
Just like the Pap test, the HPV test involves taking a sample of cells from the part of the cervix that protrudes into the vagina, as well as from the opening of the cervix.
All statutory health insurers in Germany cover the costs of an HPV test if a woman’s Pap test results are abnormal. They also usually cover the costs of the test if it is done to check how successful surgery was.
Some gynecologists offer the HPV test as part of cancer screening. It is then an individual health care service (in German: Individuelle Gesundheitsleistung, or IGeL for short), which people have to pay for themselves.
What are the advantages of screening?
The main advantage of cervical screening is that abnormal cells which might turn into cancer can be discovered and removed in time. Regular screening greatly reduces the risk of developing cervical cancer. Unpleasant and difficult treatments such as surgery, radiotherapy and chemotherapy can be avoided. And discovering cervical cancer early on may improve the chances of successful treatment.
The following tables show projections of how many women develop cervical cancer or die of it if they go for screening and if they don’t go for screening. The numbers in the column “with screening” refer to women who start going for cervical screening between the ages of 20 and 30, and who continue to go regularly for the rest of their life. Because the HPV vaccine greatly reduces the risk of cervical cancer, the projections for women who have, and haven’t, had the vaccine are shown in two separate tables.
|Not vaccinated against HPV: How many women out of 1,000 …||Without screening||With screening|
|… get cervical cancer?||30||Fewer than 1|
|… die of cervical cancer?||12||Fewer than 1|
|Vaccinated against HPV: How many women out of 1,000 …||Without screening||With screening|
|… get cervical cancer?||10||Fewer than 1|
|… die of cervical cancer?||4||Fewer than 1|
What are the disadvantages of cervical screening?
Although Pap tests and HPV tests are the best ways to detect abnormal cells early on, they do have their limits. Women who regularly have these tests will probably have “abnormal results” that turn out to be nothing serious at least once in their life.
The tests also lead to the discovery of abnormal cells that would never have turned into cancer. Once discovered, these harmless cells are often removed through a surgical procedure known as conization or a cone biopsy. Unnecessary treatments like this can’t always be avoided when people go for screening. This is because it isn’t possible to predict which abnormal cells will develop into cancer, and which won’t. But the risk of unnecessary treatment can be reduced if you wait and monitor the development of cells that have only minor or moderate changes, rather than operating straight away.
According to estimates,
- about 110 to 120 out of 1,000 women who haven’t had an HPV vaccine will have surgery (conization),
- compared to about 40 out of 1,000 women who have had an HPV vaccine.
As above, these numbers refer to women who start going for cervical screening between the ages of 20 and 30, and who continue to go regularly for the rest of their life.
What happens if you don’t go for screening every year? Are there any disadvantages?
Screening offers the most effective protection from cervical cancer if you go regularly. Generally speaking, though, only having a Pap test every two or three years is just as effective. And women then face fewer abnormal results and worry less. This reduces the risk of unnecessary treatment too.
Women can decide for themselves – or together with their doctor – when to start going for screening, and how regularly they would like to go. In most countries, cervical screening starts being offered between the ages of 20 and 30.
Does it make sense to pay for extra screening tests yourself?
A lot of doctors offer women extra screening tests which they have to pay for themselves. In Germany, these are known as individual health care services (Individuelle Gesundheitsleistungen, or IGeL for short). All of the necessary screening tests for cervical cancer are paid for by statutory health insurers. Extra tests don’t offer any advantages. Instead, they increase the risk of unnecessary worrying and unnecessary treatments due to abnormal findings that turn out to be nothing serious.
The limitations of screening
Regular screening helps to discover most abnormal cell changes early enough. One Pap test alone isn’t reliable enough, though: About half of all major cell changes aren’t discovered in this way. But those that aren’t discovered one year will usually be discovered in time through screening in the years after that. Still, there’s no guarantee that all potentially dangerous cell changes will be discovered and that cancer will always be prevented.
So it’s important to see your doctor if you notice changes such as unusual bleeding between periods or unusual discharge.
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Invitation and decision aid for cervical cancer screening; Executive report; Commission P15-02. September 29, 2017. (IQWiG reports; Volume 548).
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Benefit assessment of HPV test in primary screening for cervical cancer: Executive report; Commission S10-01. November 28, 2011. (IQWiG reports; Volume 106).
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