A liquid biopsy mainly uses blood (although it can also use urine or other body fluids) to look for the presence of malignant tumor cells or DNA fragments from tumor cells.
“The test is so named to differentiate it from solid biopsy, in which you take a fragment of the tumor and analyze it under the microscope, a more invasive technique”, explains Héber Salvador, oncological surgeon and president of SBCO (Brazilian Society of Oncological Surgery).
Currently, the test is used in some countries, Brazil among them, although the technique is still not widespread here, mainly to monitor patients who are already diagnosed with cancer.
It is possible to evaluate, for example, the effectiveness of a treatment (such as chemotherapy), and the possibility of recurrence (return of cancer) in a patient already in remission by analyzing the presence of tumor cells after the end of a treatment. Although it is already used for other types of cancer, its greatest use is in patients with colorectal cancer and lung cancer, since these are the diseases with more research that reinforce the benefits of the technique.
But according to experts interviewed by BBC News Brasil, the technique can offer much more in the future.
Through liquid biopsy, the same blood that we take to check blood glucose and cholesterol doses, according to doctors, should tell us, in the coming years, whether we have cancer cells long before a tumor appears — in addition to offering very good information. specific to the type of cancer.
This would enable early intervention, which for many cancers is the main determining factor in the success of treatment.
With the help of experts in the field, we have listed below the main negatives of liquid biopsy, what the exam already offers in terms of advantages for patients and what we can expect in the future.
Negative points
– Lack of reliability
Because the test is relatively new and has not yet reached its full technological potential, it ends up being used as a form of complementary screening.
“There is still no complete assurance that the interpretation of the liquid biopsy corresponds exactly to what is happening in the tumors and in the person’s organism”, explains Héber Salvador.
“We already have good evidence and research is growing, but I would say that, at the moment, the liquid biopsy does not give us the final word on whether a tumor exists or not, or that that patient is more likely to metastasize. Other tests need to be done.” requested.”
– Price and lack of accessibility
Depending on the test indication, the cost in the few laboratories where the test is available in Brazil varies from R$6,000 to R$15,000, according to physician Gabriela Félix, molecular geneticist and manager of the Precision Oncology Laboratory at Igenomix. Brazil. The agreements do not cover the test.
“Compared to ten or even five years ago, the price has already decreased, although it is still high. It is an impediment for many, but with the passage of time, the tendency is for the technique to become better and cheaper”, adds Thiago Bueno de Oliveira, clinical oncologist, president of the GBCP (Brazilian Head and Neck Cancer Group) and head of the ACCamargo Cancer Center.
Strengths
– Simplification of tracking
Instead of having to submit a cancer patient — who often already has impaired immunity — to solid biopsy, a surgical procedure that takes a sample of the tumor, follow-up to assess whether the disease is regressing or not can be done using liquid biopsy. .
The technique is much less invasive and brings benefits in situations such as the Covid-19 pandemic, as the patient does not need to be exposed to the hospital environment.
– Result time
Depending on the patient’s region, the laboratory services used, as well as the type of tumor, the result of a solid biopsy, explains geneticist Gabriela Félix, can take up to three months. “The liquid biopsy is ready in ten days, which facilitates the rapid start of treatment, especially for aggressive tumors.”
– Guidance of choice for treatment
“When we want to identify a specific mutation [que sabemos que responde melhor a determinados tratamentos]some of them appear in the bloodstream, and the exam allows this identification, avoiding surgical procedures”, points out clinical oncologist Thiago Bueno de Oliveira.
For the future
“Malignant cells have a characteristic that they fall into the bloodstream, which makes them able to settle elsewhere. And sometimes this happens very early, before the tumor shows signs or the mass appears on an imaging exam. So the possibility of early detection is open”, points out the oncological surgeon Héber Salvador.
Early diagnosis increases the chances of survival for patients with different types of cancers. In the case of breast cancer, for example, it is estimated that the discovery when the disease is still at an early stage represents a 90% chance of remission.
In the United States, two tests with the purpose of diagnosis are in the testing phase and could reach the market in the next two years. There is, however, no expectation that the exam will be covered by health plans anytime soon.
In addition, it is expected that with the advancement of the use of the technique, there will also be improvements in the reading of the exams, which allow a simpler reading even for doctors who are not specialists.
– Originally published text https://www.bbc.com/portuguese/geral-62088413
Chad-98Weaver, a distinguished author at NewsBulletin247, excels in the craft of article writing. With a keen eye for detail and a penchant for storytelling, Chad delivers informative and engaging content that resonates with readers across various subjects. His contributions are a testament to his dedication and expertise in the field of journalism.
