Authors: Merentsova Anastasia, Vishnevskaya Karinа
Translator: Yurankyzy Saltanat
Editor: Кigbaeva Kamilа
Detection of cancer at an early stage is especially important for the patient, because, as you know, in the later stages it is much more difficult to cure it. So, surgical removal of a tumor and relatively "soft" drugs that do not cause critical harm to the body are ineffective. There are few tests to detect the disease, and the accuracy of some of them has been questioned.
To date, researchers are mainly focused on detecting cancer in patients who have already been diagnosed. A group of scientists from the United States and China presented the PanSeer test, which detects cancer of the stomach, esophagus, lungs, liver and colorectal cancer at the earliest stages. In addition, it allows you to detect the disease four years earlier than traditional methods.
Scientists have suggested that circulating tumor DNA (ctDNA), which, as it turned out, appears in the blood 4 years before the first signs of oncology, may be a possible biomarker for cancer. Researchers have found that its study is useful for non-invasive detection of tumors, treatment and monitoring of the patient's condition during and after it. Unfortunately, there is little DNA in the blood, especially in the early stages, which makes promising diagnostic methods inaccurate.
This study was quite large-scale: it involved over 120 thousand volunteers aged 30 to 75 years. They regularly donated blood and were examined by doctors for 10 years (from 2007 to 2017). A total of 1.6 million blood samples were collected and analyzed during the study: 605 asymptomatic individuals and 191 people later diagnosed with cancer of the rectum, esophagus, liver, lungs or stomach.
The specialists also tested the plasma taken from 223 people with cancer and 200 samples of diseased and healthy tissues, which made it possible to find cancer markers, small fragments of circulating tumor DNA and develop a test based on them. Simultaneously, for the purpose of comparative analysis, traditional examinations of cancer patients were carried out.
According to the results of the study, the new method made it possible to identify the development of five common types of the disease with an accuracy of 95% four years before the diagnosis of cancer using traditional instrumental and laboratory methods. “We have moved from a proof-of-concept test of producing a reliable and inexpensive commercial product that can be used in hospitals,” said study co-author Kong Zhang.
However, this test also has a number of disadvantages: despite the fact that it is capable of detecting oncology, the test cannot determine which tissues are affected. According to the authors of the work, their development is a step away from clinical research and the possibility of being applied in hospitals. In the near future, scientists are going to test subjects based on heredity, age, lifestyle and other factors, which will make the test more accurate.
Source: https://www.nature.com/articles/s41467-020-17316-z#Sec10
