Cancer screening: can cancer be detected early with a blood test?

Early detection: cancer diagnosis from the blood?
As with many other diseases, the same applies to cancer: the earlier the diagnosis, the better the chances of recovery. Among other things, hopes are placed in a blood test that should make other tests superfluous. But how far is research in this area? Experts provide information.

One of the most common causes of death in Germany
Cancer is still one of the diseases from which most Germans die. Health experts repeatedly point out ways of reducing personal cancer risk. In addition to a healthy lifestyle with regular exercise, a balanced diet and not consuming alcohol and cigarettes, medical check-ups should also be mentioned here. In the future, a simple blood test could lead to cancer diagnosis - or the all-clear.

Can a blood test make mammography and colonoscopy unnecessary?
Can a simple blood test replace the invasive removal of tumor tissue? Can a few milliliters of blood even make mammography and colonoscopy superfluous? What is it about the blood cancer test, the liquid biopsy?

The German Cancer Research Center (DKFZ) is asking these questions in a current report on the occasion of World Cancer Day on February 4. The experts provide information on the current state of research: what is already possible today and what can be expected in the near future?

Early diagnosis
In recent years, research on a blood test to improve cancer diagnosis has been reported time and again. Scientists at the DKFZ were also involved in the search for a test for early cancer diagnosis.

About a year ago, the Californian company "Grail" announced a blood test for the early detection of all conceivable types of cancer in healthy people, according to the current release. The market launch is expected to be in 2019.

The DKFZ experts explain the biological background of the test: According to this, genetic material from cancer cells or whole cancer cells continuously enter the blood. Evidence of this is referred to as a “liquid biopsy”. Every tumor has its characteristic pattern of cancer-specific genetic changes. Scientists can track down the cancerous DNA snippets.

Can survival be extended or quality of life improved?
“In many cases, it is already possible to track cancer patients after treatment based on the detection of DNA in the blood to determine whether the tumor is returning. Therefore, the vision has developed that in the future tests for tumor DNA in the blood could also be used for the early detection of cancer. However, there is no data on this so far. That means the hypothesis on which this vision is based must first be proven, ”explained Peter Lichter, head of the Molecular Genetics department at the DKFZ.

"Even if such proof should turn out to be technically feasible: As with other early detection examinations, it would have to be shown that it actually benefits people, that it extends survival time or improves quality of life," added Susanne Weg-Remers, of the DKFZ runs the cancer information service.

Monitoring the course of therapy
Holger Suelmann, head of the cancer genome research group at the DKFZ, thinks it is only a matter of time before tests for tumor DNA in the blood are given clinical approval in cancer medicine. Initially, however, these will not be cancer screening tests.

The development of tests to monitor the course of therapy for already diagnosed cancer has progressed significantly further. “Unlike tumor tissue samples, blood can easily be taken several times at short intervals. This enables us to track whether and for how long the cancer responds to a drug. This is important because cancer cells quickly develop resistance to many active substances, ”says Suelmann.

In his opinion, it is still too early to estimate when a DNA test for cancer screening will actually be available.

Identify the most effective drug
According to the experts, the long-term goal is to use a blood test to identify the most effective drug for the individual patient - even without first having to analyze the tumor tissue.

Because many of the cancerous genetic changes that can be detected with the Liquid Biopsy are the decisive drivers of tumor growth. With targeted drugs they could be blocked and the cancer stopped.

According to Suelmann, it is not yet possible to predict whether this will work at all and, if so, for which types of cancer.

He said: “I assume that the liquid biopsy will take a place in cancer medicine - for specific questions about certain types of cancer. There will be no general "cancer test" for the foreseeable future. "

New investigations have no routine applications
"Some patients who call us fear that the cancer will return and hope to detect this as early as possible with regular blood tests. Others have the idea that a liquid biopsy can prevent invasive surgery to remove tumor tissue and are wondering whether this could be an option for them, ”says Weg-Remers.

"Unfortunately, almost all of these new examinations have not yet reached routine clinical care and should only be used in studies if possible. The Cancer Information Service will be happy to answer any questions you may have about the current status of developments in this field - by phone or email. ”(Ad)

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