Thanks to a blood test detecting tumor markers, it is possible to identify patients at risk of relapse and assess the effectiveness of treatments.
Identifying early signs of cancer relapse is one of the major challenges in oncology. A challenge that seems to be able to meet the blood test developed by researchers at the Ludwig research center. Featured this week in the prestigious magazine Science Translational Medicine, this discovery is an important step in the development of non-invasive tests that are more effective than existing ones.
The research team, in collaboration with researchers from the University of Melbourne (Australia) and the Johns Hopkins Kimmel Cancer Center (United States) focused on colon cancer because the tests used today do not do not predict the risk of recurrence.
More efficient than radiology
Guided by technological advances and advances in genetics, researchers have developed a blood test capable of detecting circulating tumor DNA (ctDNA), small pieces of DNA released into the blood by cancer cells when they die.
Using this technique, also called liquid biopsy, researchers can gauge the risk of relapse because the amount of ctDNA is proportional to the amount of cancer cells. Their work even suggests that it can detect residual disease well before X-ray examinations. Better still, it makes it possible to evaluate the effectiveness of the chemotherapy carried out after an operation.
“We have succeeded in identifying the only fragment of tumor DNA among the 10,000 healthy fragments circulating in the blood of patients,” explains Jeanne Tie, researcher at the Ludwig center and responsible for the work. We had not yet reached this level of sensitivity that we needed, but it is now done ”.
To achieve this, scientists collected and analyzed blood samples taken from 230 patients with colorectal cancer. Between 4 and 10 weeks after their tumors were removed, the participants had their blood drawn again.
After the operation, 20 patients still had ActDNA in their blood, and of these, 80% relapsed within two years. And of the 164 patients who no longer had ctDNA, 10% had their cancer come back. “A positive test means that the cells causing the tumor are hiding somewhere in the body,” said Peter Gibbs, co-author of the study.
Personalized medicine
Thus, after their operation, 6 patients who had a positive result underwent chemotherapy to eliminate the remaining cells. There again, the researchers collected the blood of the patients in order to follow the evolution of the disease, but also the effectiveness of the treatments.
They then observed that the tests were negative for two patients. “For an oncologist, this is surely the most interesting aspect of ctDNA detection because it can be used not only to determine the risk of relapse but also to assess in real time the benefits of chemotherapy”, emphasizes Peter. Gibbs.
Ultimately, the researchers hope that the liquid biopsy will replace the tumor biopsy, the benchmark examination today, to follow the evolution of cancers. Other promises of this technique: early detection and the development of personalized medicine by identifying mutations specific to each patient directly in their blood.
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