Liquid biopsy as an alternative in cancer diagnosis

A liquid biopsy consists of a laboratory analysis of one or more samples of blood, urine, or other body fluid.CORD PRESS

precision medicine brings great progress in the study of numerous diseases, as is the case in a very alarming case cancer. Usage liquid biopsya test that in some cases may be complementary or alternative to tumor tissue biopsy and may improve cancer diagnosis.

And the usual thing to diagnose cancer and see its evolution is to perform a biopsy of tumor tissue, invasive methods that require surgery or puncture; While liquid biopsies are achieved through a blood test (the most common) or collection of urine or other body fluid samples, they are non-invasive methods that are not very taxing for patients.

It consists of testing one or more samples of blood, urine, or other body fluid in a laboratory to check for the presence of cancer cells in the tumor or small pieces of DNA or other molecules that tumor cells release into body fluids. as described in detail by the US National Cancer Institute (NIH).

“The ability to take multiple samples over time facilitates the analysis and understanding of genetic or molecular changes occurring in a tumor,” the facility describes.

Thus, it highlights that among the advantages of liquid biopsy is that based on these samples, one can better plan treatment, see whether they are effective or not, know whether cancer is present or not at a certain time, and also determine if cancer is present. at an early stage or has progressed.

Why liquid biopsy is not used more often

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In an interview with Infosalus Vice President of the Spanish Association for Cancer Research (ASEICA), Dr. Rafael Lopezwho in January coordinated the IX Symposium on Liquid Biopsy at a scientific level, says that Spain was a pioneer in the introduction of this technique, although it is currently falling from the top positions: “If we compare ourselves with Western Europe and the United States lags behind us: “ As Europe’s fourth economic power, we must be higher than we are in its implementation.”

In an interview with Infosalus he claims that This examination is carried out in almost all hospitals. third level of Spanish, so today all patients and oncologists have access to the procedure.

Dr. Lopez, however, argues that the biggest challenge facing wider adoption today is economic: “The cost is high and there is no good research into what it can save. There are difficulties with implementation at the technical level; this is a complex technique. which also requires knowledge, provides complex information for which the presence of knowledge is necessary for its interpretation.”

In his opinion, its main advantage is that with a small amount of blood or biological fluid, it is possible to study the tumor using the most complex techniques available today. “It’s a simple technique that can be repeated indefinitely, and it can capture all the heterogeneity of a tumor,” he explains.

Nevertheless, believes that liquid biopsy is a fundamental treatment method and diseases, not so much for diagnosis, but in order to find out which drug is most suitable for the patient at a given moment of the disease, especially in the later stages.

Its role in minimal residual disease is also highlighted, since it serves to check whether the tumor has disappeared after treatment or, on the contrary, there are microscopic remains that cannot be seen either with x-rays or with surgery: “It has many advantages over minimal residual disease.

and many treatments that are now prescribed and make no sense could be avoided. But we also do not have the tools to discriminate, and in such cases their implementation needs to be accelerated.”

“This is a more complex blood test than the usual one, which is not yet carried out in all Spanish hospitals. It still needs to be implemented in everyday practice, as there are targets that have not yet been demonstrated with this laboratory test,” he says. interview with Infosalus President of the Oncological Society of Galicia, Dr. Martin Lazaro

current Head of the Oncology Department of the Alvaro Cunqueiro Hospital in Vigo and organizer of the National Symposium on Precision Oncology, which will take place in February.

For what cancers is it most often used?

He says that in Lung cancer is where it is studied the most and developed this test; although colon or prostate cancer is also mentioned here, as is melanoma. “It can be useful for many tumors, but the most indicative is lung cancer,” says the oncologist.

“For example, with targeted treatments for lung cancer, if there is progression of the disease, a tissue biopsy or liquid biopsy can be done, where the presence of a resistance mutation can be tested (whether the treatment works or not). .), so a different treatment needs to be used,” he adds.

For his part, ASEICA Vice President Dr. Lopez claims that its potential will facilitate early diagnosis of up to 20 different types of tumors. He says the United States has already approved the first test for early diagnosis of two dozen tumors and is studying at least three or four different tests. European health care system.” Please note that hePathologies that bring the greatest benefit liquid biopsies are cancerous lungs, mammary gland, digestive and genitourinary systems.

A non-invasive method that can predict whether a patient will respond to treatment or not.

Another advantage Dr. Lazaro points out is that liquid biopsy avoids taking a tissue sample, which is difficult due to the location of the tumor or the patient’s comorbidities. “It has been observed that serial liquid biopsy can predict whether a patient will respond to treatment; and obtain an accurate diagnosis before tumor changes are reflected in imaging tests (for example, CT or MRI),” explains the President of the Galician Oncological Society.

Another advantage, according to Dr. Lazaro, is that after local treatment, a positive liquid biopsy may indicate that traces of the disease are still present, “and it has been observed that in these cases the prognosis may be worse, indicating on the fact that some additional treatment (chemotherapy, radiation therapy, immunotherapy, etc.).”

In addition, it is emphasized that this test can also help select more personalized patient treatment, when choosing which drug to use if the disease progresses and certain changes occur. “For example, lung cancer uses drugs that target a specific genetic change. As the disease progresses, another mutation arises, which can be detected in the liquid biopsy,” he explains.

A revolution in the fight against cancer

At the same time, this doctor emphasizes that today liquid biopsy is considered a “revolution in cancer diagnosis” because it can help in making a diagnosis as well as monitoring patients, all with the help of a blood sample. “If this is realized, it will be a revolution, because with the help of a blood test we will get information that cannot be obtained in any other way,” says Martin Lazaro.

Among its main tasks today will be to determine in what other diseases besides those mentioned it may be useful; know the ideal time for this; and after its implementation will be included in the portfolio of services of all healthcare systems, he believes.

According to ASEICA Vice President Dr. Lopez, this should be a cheaper test and also more sensitive, in order to increasingly address minimal residual disease and, above all, in the future, early diagnosis.

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