Aug 28, 2020
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The voice of the blood. Scientists have learned to diagnose cancer at an early stage

A test has been created that detects cancer 4 years before the first symptoms appear.

Scientists managed to find markers of early development of cancer in the blood.

Cancer is sometimes aggressive. And then the patient, unfortunately, burns out in a matter of months. But more often tumors mature for a long time - especially in older people. Sometimes it takes more than one year from the moment the tumor forms until the first signs appear. And when a person finally finds out about his diagnosis, it often turns out that there are not so many opportunities to help him.

Recognize in the bud

For oncologists, early detection of a tumor is task number 1. Despite the fact that diagnostic methods are constantly being improved, many of them are still unable to see cancer in the embryo. For example, PET / CT scanners do not see a tumor smaller than 4–5 mm.

Blood is the first to react to cancer in the body.

“A growing tumor releases toxic metabolic products into the bloodstream,” says Candidate of Medical Sciences, Head. molecular biological laboratory of N.N. Blokhin Anna Stroganova. “Therefore, it is sometimes possible to suspect an oncological process in the body by both general and biochemical blood tests, especially if it is combined with such signs as fatigue, weakness, weight loss.”

However, indirect signs are not so indicative. Tumor markers are considered to be a more accurate diagnostic method. In some commercial clinics, the analysis for tumor markers is positioned as a method of early diagnosis of cancer.

“Tumor markers cannot be considered a method for early diagnosis of cancer. The single most sensitive tumor marker is PSA, a marker of prostate cancer, says Director of the Center for Molecular Oncology "Onco Atlas" Vladislav Mileiko. - Other tumor markers are needed to monitor the dynamics of disease development and assess the effectiveness of therapy. This is due to the fact that they can change not only in response to the presence or absence of a malignant process in the body, but also to other changes not associated with tumors. "

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Click to enlarge

Identify, not predict

However, if specific tumor markers have not yet been found, this does not mean that ultra-early diagnosis of cancer by blood analysis is impossible. This was proved by scientists from the United States and China, who developed a method that allowed using blood samples with an accuracy of 91% to detect five forms of cancer (stomach, esophagus, lungs, liver, and also colorectal cancer) 1–4 years before the first signs of the disease appeared.

For this, scientists have been collecting blood tests from 120 thousand people for 10 years. Everyone was regularly tested and examined. Thanks to this, the scientists had at their disposal blood samples from onco patients taken long before they were officially diagnosed with cancer.

This allowed the researchers to find markers of the early development of the disease in the blood and develop on their basis a test that detects cancer at a stage when other diagnostic methods are powerless.

“This method does not predict cancer that will appear in the future, but detects asymptomatic patients, since it allows detecting modifications in the DNA structure even before the clinical manifestation of the disease,” explains A. Stroganova. “It is valuable that the test is designed to diagnose those types of cancer that are today detected using complex invasive studies (gastroscopy, colonoscopy, etc.).”

Readiness number 1

How soon can this test appear in our country?

“The method that made it possible to create the test (analysis of DNA methylation - recognition of molecules attached to a region of the genome) is a complex molecular genetic study, and therefore extremely expensive,” says A. Stroganova. - So far, it is used only as an experimental technique. After revision, it will be used to examine patients from risk groups (with a burdened hereditary history), after which it will be released into wide clinical practice in other countries.

The new test is unique, but not the only development. The search for markers of early carcinogenesis is carried out in many scientific centers, including the N.N. Blokhin. We are also studying various gene modifications that will allow in the near future to identify patients with an early stage of the oncological process. "

“If we talk about early diagnosis, then there are two global paths: new scientific developments that allow to identify already existing cancer at early stages, and the management of individual cancer risks,” explains V. Mileiko. - Already today, genetic studies are available to identify the carriage of gene variants associated with hereditary forms of cancer. The assessment of individual risks is also of great importance: this allows you to choose a personal prevention program. All over the world, genetic testing is used for this, which helps to identify healthy carriers of hereditary oncological syndromes and to take control of the processes even before the disease manifests itself. If you suspect a hereditary syndrome, you should undergo genetic testing, calculate the individual risk of the disease for each family member, draw up a plan for regular examinations and prevention. "

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