Cervical cancer: What are the benefits of HPV tests for cervical screening?
Pap tests aren't the only way to screen for cervical cancer. HPV tests can be used for this purpose too. They are actually even more effective at detecting abnormal tissue that could turn into cancer.
Cervical cancer (cervical carcinoma) is a type of cancer that grows at the opening of the cervix, which is found at the bottom of the womb. About 4,600 women get cervical cancer in Germany each year. Cervical cancer develops from a persistent infection with human papillomaviruses (HPV). If the viruses stay in the mucous membrane cells of the cervix for a long time, then the cells can change over time, and eventually develop into cancer after many years. But the vast majority of HPV infections aren't dangerous and clear up on their own.
Screening tests for cervical cancer
Cervical cancer doesn't cause any symptoms at first, or only very few, so it is often not detected for a long time. If women have symptoms such as frequent vaginal bleeding between periods, the cancer might already be at quite an advanced stage. The goal of screening tests is to detect cell changes (dysplasia) early enough for them to be treated successfully before cancer has a chance to develop.
Pap tests (also called smear tests) have been used to screen for cervical cancer in Germany since the 1970s. This test involves examining cells on the cervix to detect any changes. In Germany, women who have statutory health insurance are entitled to have one free Pap test per year from the age of 20 onwards.
A test for human papillomaviruses (HPV test) can be done to find out whether a woman has an HPV infection and is therefore at greater risk of cervical cancer. But the HPV test can't detect abnormal cell changes. For this reason, if the HPV test shows that a woman has an HPV infection, she will have to have a Pap test and perhaps other tests too. HPV tests aren't currently used in routine cancer screening in Germany. Instead, they are offered as an individual health care service (in German: Individuelle Gesundheitsleistung, or IGeL for short), which people have to pay for themselves. But all of the health insurance funds in Germany cover the costs of the test in certain situations, for example if a woman’s Pap test results are abnormal, or to check whether cervical surgery was successful. There are plans to routinely offer HPV tests together with Pap tests for screening purposes in the future.
Research on the benefits of HPV tests
Several large studies have compared HPV tests with Pap tests to see what advantages they have in cervical screening. The studies looked into whether HPV tests are better at detecting high-grade dysplasia (abnormal cells that have changed a lot) and preventing cervical cancer. A total of more than 235,000 women participated in the six studies. HPV tests were used in very different ways in these studies. For example, sometimes they were used instead of Pap tests, and sometimes they were used in addition to Pap tests. In the studies, both of the tests were carried out every 3 to 5 years.This is different to the situation in Germany, where Pap tests are offered once a year.
HPV tests could have benefits in cancer screening
The results of these studies show that HPV tests are more effective than Pap tests at discovering high-grade dysplasia (abnormal cells that are likely to turn into cancer). Individual Pap tests fail to detect half of all cases of dysplasia. HPV tests help to detect a lot more cases.
If Pap tests and HPV tests are carried out regularly over a long time period, both detect most areas of abnormal cells. But HPV tests were slightly more effective overall: Fewer women who had HPV tests developed cervical cancer. The studies lasted about five years. This is what was found during that time:
- About 4 out of 10,000 women developed cervical cancer if they only had Pap tests.
- And about 1 out of 10,000 women who had HPV tests (in addition to, or instead of, Pap tests) developed cervical cancer.
But the studies didn't allow any conclusions to be drawn about whether women who had an HPV tests were less likely to die of cervical cancer.
HPV tests can also have disadvantages. Many abnormal cells don't develop into cervical cancer. This means that, compared to Pap tests, HPV tests might also be more likely to detect abnormal cell changes that would have returned to normal on their own and never developed into cancer. This kind of diagnosis is of no benefit to women and might lead to unnecessary treatment, such as surgery to remove tissue from the cervix (conization). But it's not clear how many women were affected by this in the studies.
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Benefit assessment of HPV test in primary screening for cervical cancer. Final report; Commission S10-01. November 28, 2011. (IQWiG reports; Volume 106).
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Benefit assessment of an HPV test in primary screening for cervical cancer. Update; Rapid Report; Commission S13-03. May 14, 2014. (IQWiG reports; Volume 222).
This health information is a summary of a scientific report published by IQWiG. It is not an assessment of the right to have health care services paid for by statutory health insurance funds in Germany. By law, decisions about paying the costs for diagnostic and therapeutic procedures can only be made by the German Federal Joint Committee (G-BA). The G-BA takes IQWiG reports into consideration in its decision-making process. You can find information about the decisions of the German Federal Joint Committee on its website.