Early cancer detection with blood test: All about Liquid Biopsy

Blood sampling can provide information about various things. Deficiency symptoms, problems with the thyroid gland, inflammation values ​​- and also whether a patient has cancer or not. “Liquid Biopsy” makes it possible: Samples of non-solid, biological tissue, especially blood, are examined largely non-invasively. Similar to conventional biopsy, this procedure is well suited for the diagnosis and monitoring of cancer. And here is a new milestone to be announced. The “Deutsche Ärzteblatt” reports on this among other things.

There have been several possible test procedures for various types of cancer via liquid biopsy. We will introduce one of them to you below. Now researchers have managed to get one Develop a blood test that detects 50 different types of cancer via Liquid Biopsy can.

Detect 50 types of cancer: This is how the Liquid Biopsy works

A prospective case-control study, published in the Annals of Oncology, showed that the test, developed by a US company, can detect 50 different types of cancer. And the further astonishing thing about it: The false positive rate, i.e. the rate of cases that were diagnosed but in which there was no illness at all, was only 0.7 percent! This false positive rate was a problem that previous tests had to grapple with, as it has been much higher so far.

How does it all work? A liquid biopsy test detects genetic mutations in cancer cells via DNA. Cancer is basically the result of mutations and other changes in the genome. The mutated cells, cancer cells, multiply and form a tumor in most cancers. When cancer cells decay as a tumor grows, fragments of their DNA flow into the blood. If these changes in the blood can now be detected, it can quickly be determined whether the person tested has cancer or not. So far, this can only be demonstrated with some cancers if the tumor is large enough. With cancer, however, it is often vital for the survival that the disease is recognized as early as possible.

The problem is that these DNA fragments can be so different that it is difficult to identify them precisely. And now the breakthrough could have been achieved.

Method can distinguish fragments of DNA

First of all, a common denominator had to be found. And the US company “Grail” might have found it. With their test, so-called “methylation patterns” of the cell-free DNA detected in the blood can be determined – and thus DNA fragments from cancer cells can be distinguished from cell-free DNA from body cells. These methylation patterns also indicate what type of cancer it is.

To test whether this test is reliable, studies were carried out on blood samples from almost 6,700 people. Around 2,500 of these had a known cancer, but have not yet been treated. 4,200 other people without cancer were tested.

In doing so, it was possible to find out which patterns could be specific for a cancer, ie which they could show. According to the researchers around Michael Seiden from “US Oncology” (private provider of cancer treatments from Houston, USA), a specificity of 99.3 percent was achieved. Accordingly, the test was only positive in 0.7 percent of the study participants who did not suffer from cancer.

This result is so important because unnecessary follow-up examinations, which are expensive on the one hand, and above all, on the other hand, leave the false-positive people in an uncertainty that is difficult to bear. Because they believe that they have cancer, even though they are actually not.

The higher the stage, the better the detection rate

A liquid biopsy would have the greatest benefit if it recognizes cancer as early as possible, i.e. best in the first two stages. The detection rate for the correctly positively recognized cancers is not so high – it was around 67 percent for the twelve most deadly cancers. This affects anal, bladder, colon, esophagus, stomach, head and neck cancer, cancer of the liver and bile ducts, lung, ovary and pancreatic cancer, lymphoma / leukemia and multiple myeloma. The detection rate was highest in the advanced stage. But even in the early stages it was 39 percent in stage I and 69 percent in stage II for the twelve diseases mentioned above. In all 50 types of cancer tested, it averaged 18 percent in stage I, 43 percent in stage II, 81 Percent in stage III and 94 percent in stage IV.

Further studies are now to follow

Now two more studies are to follow: The so-called SUMMIT study is to test how successful the blood test for early detection can be on 50,000 people with an increased risk of cancer due to long-term tobacco use. And the PATHFINDER study examines how this test could be integrated into practice.

The test could also be of interest to patients in whom tumor metastases have been found whose origin, i.e. the primary tumor, is still unknown. In the study, it was possible to identify the origin of the cancer in 96 percent of the cases – using the methylation pattern of cell-free DNA mentioned above.

The cancer diagnosis ensures a life between fear and hope. There are more guides and articles about cancer on our topic page.

Here you can find the current study in the “Annals of Oncology” in English.

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On January 22, 2018, BILD der FRAU reported another test using the “liquid biopsy” method:

Scientists from the “Johns Hopkins” University in Baltimore have just published a report in the journal “Science” that a procedure called “Liquid Biopsy” (English “liquid biopsy”) can detect eight different types of cancer at an early stage. This would revolutionize cancer prevention, which has so far been associated with frequently unpleasant examinations such as mammography or colonoscopy.

“Liquid Biopsy”: cancer detection thanks to special blood analysis

For the study at the “Johns Hopkins” University, blood was drawn from over a thousand people with cancer and analyzed using the “Liquid Biopsy” method. Even the smallest particles in the blood are detected, which indicate certain cancers. Cancer was also found in the blood test in 70 percent of the people tested. The test can detect the following types of cancer:

• Breast cancer
• Colon cancer
• Liver cancer
• Lung cancer
• Ovarian cancer
• Pancreatic cancer
• Esophageal cancer
• Stomach cancer

Such a form of diagnosis would have countless advantages for those affected. Blood sampling is simple and straightforward for the patient – no comparison with some other examinations. In addition, doctors could discover some particularly aggressive types of cancer at an early stage, which would significantly increase the chances of recovery. For patients who have already had cancer, a regular blood test could provide information on whether there is a risk of relapse.

Process not yet fully developed

Although the progress in research on “Liquid Biopsy” is really promising, you shouldn’t be too early to look forward to it. The process is not yet mature enough to actually become common practice. The following problems still have to be solved:

• According to German experts, the risk of mistaken cancer diagnoses is very high. This could lead to patient insecurity and unnecessary follow-up examinations.
• The location of the tumor cannot be determined by the blood test in all cases. For the patient, that means knowing that you have cancer, but not where it is. Very difficult for the psyche and further treatment.
• So far, the method has only been used in patients with cancer. But: “With a recognized screening procedure, a single person suffering from cancer must be correctly identified without symptoms from several hundred healthy people and people with other illnesses,” says the German Society for Pathology in a statement on the procedure.

So there is still a lot to do for the Baltimore researchers. But there is no doubt that their work gives hope for a healthier future.

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