Tailoring precise cancer treatment begins in the laboratory
Genomic tests have become the standard in recent years in order to match each patient with the correct and precise cancer treatment.
Today there is a wide variety of tests, but how do you know for whom each test is suitable?
The answers are inside
In collaboration with Oncotest
Monday, August 15, 2022, 09:51 Updated: 11:31
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The most comprehensive genomic tests are those that are done by sequencing hundreds of genes at the same time (Photo: ShutterStock)
Until a few years ago, cancer patients were treated with therapeutic protocols according to the location of the tumor, usually with chemotherapy, but today, the treatment of cancer diseases has undergone a real revolution and more and more target-oriented drugs are used that are adapted to each patient specifically.
Targeted treatment is adjusted based on the specific tumor characteristics of each patient.
In recent years, there has been an offer of many and varied biological and immunotherapeutic treatments.
Thanks to the development of science and technology, it is possible to carry out genomic tests in order to accurately map the genomic profile of a specific patient's tumor.
The tests examine hundreds of genes in order to find changes (mutations) in the tumor cells.
This actually allows the attending physician to adjust the most appropriate and accurate treatment for his patients.
Innovative genomic tests are based on NGS (Next Generation Sequencing) DNA sequencing technology and have become a significant tool that serves as a sort of 'compass' for doctors when faced with a treatment decision. Here are some of the breakthroughs that have changed the way cancer is treated - starting with tests For deep and comprehensive genomic sequencing to a simple blood test that can predict the risk of disease recurrence in the future.
In recent years, there has been an offer of many and varied biological and immunotherapeutic treatments (Photo: ShutterStock)
Testing of about 650 genes to adjust the treatment The
most comprehensive genomic tests are those that are done by sequencing hundreds of genes at the same time.
The tests examine genomic changes (also called mutations) in the DNA of the cancer cells. The mutations occur when a change in the DNA code sequence occurs in a gene. It is important to know that mutations occur all the time, but the body knows how to fix them regularly. In some cases, Those mutations that the body is unable to repair lead to the formation of cancer cells.
A genomic test may detect the same changes in several genes, and today some cancer patients in Israel are entitled to such an NGS test, free of charge, as part of the drug basket. For example, all lung cancer patients in Israel are entitled to a genomic panel of the type NGS, which is performed in one of 12 pathology laboratories in Israeli hospitals. Children diagnosed with cancer - of any kind - are also entitled to receive a genomic diagnosis as part of the health services basket.
There are also comprehensive tests that are performed in large laboratories abroad and are able to provide a broader picture of the disease. One of the leading tests in the world is the TempusxT test by the Oncotest company. This is a test that was developed based on the understanding that there is a need to sequence not only the DNA of the tumor, but also his RNA, in order to increase the chances of matching treatment. The test performs deep genetic sequencing of 648 common genes from a biopsy taken from tumor tissue. The test compares the findings in the tumor to the sequencing of the same genes in the patient's normal tissue (using A blood or saliva test.) A comparison between the findings found in the tumor and those found in the patient's normal tissue can help locate only the mutations that are responsible for the disease and avoid inappropriate treatments.
In addition, this test also has the ability to identify the source of the cancerous tumor in cases where patients were diagnosed with cancer "of unknown origin".
About 2-5% of all cancer patients do not know the origin of the tumor, and without this information the medical team will have difficulty providing accurate treatment.
In recent years, there is the ability to perform genomic mapping also through a simple blood test (Photo: ShutterStock)
A simple blood test to adjust precise treatments
In recent years, there is the ability to perform genomic mapping also through a simple blood test also called "liquid biopsy".
Liquid biopsy-based Genomic Clear allows for locating and sequencing DNA segments from the source of tumors from the bloodstream. The world's leading and most sensitive test of the "liquid biopsy" type is the "Guardant 360" test from the Oncotest company. In addition to its high level of accuracy, it also provides a quick answer within 7 days Detection of a mutation in DNA from a tumor source from a blood sample can influence the choice of a more accurate treatment for the patient and is already widely used in a wide variety of malignant diseases.
The use of liquid biopsy will usually be done when there is difficulty in taking a sample of tumor tissue (biopsy) from the patient or when there is concern that this invasive operation may endanger him.
In addition, during the treatment of the disease, the cancerous tumor undergoes changes and sometimes new mutations are created.
Therefore, it is customary to perform a liquid biopsy even during the treatment of the disease, such as in the case that the patient stops responding to the treatment.
The test helps identify new findings that may indicate additional treatment options.
Identify the microscopic cells and prevent disease recurrence
The liquid biopsy technology can also help at another significant crossroads in the treatment of cancer.
Patients who were diagnosed with cancer (for example colon cancer) in the early stage of the disease - stage 2 and undergo surgery to remove the tumor, it is possible to find out if there is residual microscopic disease that can cause the disease to recur in the future, therefore it is necessary to treat these patients with complementary or preventive treatment - usually chemotherapy treatment .
However, while for some patients it is an important, necessary and life-saving treatment, for others it will be an unnecessary treatment with side effects in the short and long term.
Hence, after surgery, an effective and accurate tool is needed to assess whether there are any residual disease in the patient and how much the patient is at risk of future recurrence of the cancer.
Approximately 15% of patients diagnosed with stage 2 colon cancer and approximately 30% of stage 3 colon cancer patients will experience disease recurrence within 5 years after surgery alone without the addition of supportive chemical treatment. Therefore, there is a need to identify the groups of patients who will benefit from receiving chemotherapy.
"Guardant Reveal" type liquid biopsy is an important tool in planning the treatment of colon cancer patients, stage 2 after surgery to remove the tumor.
The uniqueness of the "Guardian Rebil" test is its ability to detect minimal disease remnants in the blood (also called MRD).
The test is considered particularly sensitive to the extent that it is able to detect DNA traces of the tumor in the blood even at a low incidence of 0.01%. In a study published this year in the most respected scientific journal in the world - "New England Journal of Medicine" (NEJM) it was proven that the use of MRD tests Effectively locates which of the patients is at high risk of disease recurrence after surgery and needs chemotherapy as a preventive treatment and which of the patients can be spared the unnecessary treatment.
The use of liquid biopsy is gaining momentum in more and more therapeutic decision points for cancer.
In the near future, tests of this kind will also be used for the initial diagnosis of various cancers as part of screening tests for at-risk populations and even for the general population over the age of 50.