Genetic testing helps tumor targeted drug therapy.
2020-05-18
The emergence of targeted therapy is accompanied by the study of tumor gene molecular biology. Through genetic research, the medical community finally confirmed that the tumor is caused by a mutant cell in the human body.
And it is believed that tumor-related genes include: oncogenes, tumor suppressor genes, tumor multidrug resistance genes, tumor metastasis related genes, etc.
What is targeted therapy and how is it different from traditional cancer chemotherapy?
Targeted therapy refers to the design of corresponding therapeutic drugs through genetic testing at the molecular level of cells. After the drug enters the body, it will recognize the target. After recognition, it directly acts on the target organ, causing the tumor cells to specifically die, without affecting the normal cell tissue around the tumor.
To put it simply, the therapeutic drugs can directly target the tumor cells to carry out targeted attacks. The reason for the targeted attacks is because there are specific proteins on the surface of the tumor cells that are not found in normal cells, and the drugs can recognize these specific proteins.
Chemotherapy is the use of some drugs to kill the activity of tumor cells. Tumor cells grow fast in the body, and the drugs used in chemotherapy are more sensitive to the cells that grow faster, so chemotherapy can kill tumor cells to a certain extent.
However, due to the rapid growth of the body, not only tumor cells, but also bone marrow cells, hair follicle cells, etc., chemotherapy drugs will be killed together, which is also the cause of white blood cell reduction and hair loss during chemotherapy.
Chemotherapy works well, but the side effects are also great. Targeted therapy has fewer side effects. Doctors need to choose medication based on the patient's physical condition and tumor cells. Due to the complexity of some tumors, even if targeted therapy is used, it may not be able to obtain obvious benefits.
When doctors use targeted therapy for patients, in addition to considering whether the patient can benefit, the safety of treatment, etc., the patient's economic ability also needs to be considered.
Genetic testing determines the success or failure of personalized targeted therapy
Targeted drugs are not effective for all cancer patients. Clinical results show that the average effective rate of using targeted drugs without screening is only 30% -40%. Therefore, before taking targeted drugs, you need to conduct targeted drug screening through genetic testing.
The efficacy of targeted drugs is closely related to the state of gene mutation. The US Food and Drug Administration (FDA) stipulates that doctors must perform genetic testing for patients before they prescribe targeted drugs. Although there is no mandatory requirement in China, the drug's instructions clearly indicate the target of the drug.
For example: *** The instructions for the drug clearly indicate: "Patients who choose to use this drug for treatment must be diagnosed as a type ** tumor by a trained professional technician using a fully validated test method.
Be sure to take targeted drugs under the guidance of professional doctors, and avoid making unauthorized claims!
Which genes should be tested first in genetic testing?
As long as there is a corresponding drug-targeting gene, it needs to be tested.
For example, there are now targeted drugs for EGFR gene mutations, such as gefitinib, erlotinib, icotinib, etc. Therefore, the EGFR gene must be tested.
In addition, there is currently a targeted drug, crizotinib, which has a good effect on patients with ALK fusion gene mutations, ROS1 gene mutations, and rare NKRP1 fusion gene mutations.
There is also a special gene: HER2, which was originally a mutation in breast cancer patients, but why can lung cancer patients also do it?
At present, there seems to be some changes in the direction of international cancer treatment. A new concept of the same treatment for different cancers has been introduced, which basically means that there is no distinction between cancer types and genes. For example, even for patients with lung cancer, if a mutation in the HER2 gene is detected, using the corresponding targeted drug Herceptin can also achieve therapeutic effects!
Therefore, for patients with better family conditions, it is recommended that if there are available drug genes, testing is required. But if the economy is really under pressure, it is recommended to do the most common genetic testing of three targets: EGFR, ALK, ROS1.
Can targeted therapy not be genetically tested?
In the course of cancer treatment, some people choose not to do genetic testing before receiving targeted therapy, and this treatment is called a blind test.
Compared to genetic testing, blind testing also has its own advantages, such as saving money and time. So in what circumstances can skip genetic testing and directly target therapy?
Single targeted drug
Some types of cancer may have a single mutation type, and there is no room for targeted drugs. In this case, you can choose a blind test and change other treatments once you find no effect.
Lifetime is not optimistic
For some cancer patients, the doctor's estimated survival time is less than 6 months, and the financial conditions are not good. In this case, if you take half a month to wait for an uncertain result, it seems too risky, so it is better to conduct a blind test directly , Use money on the blade, choose the most probable to try, commonly known as "Chuangyun".
Of course, the blind test also has its own shortcomings. Before there is no genetic test, the medication basically depends on "guessing", and the effect is basically relying on "praying." Therefore, when treating cancer patients, you should consult the attending doctor about whether to conduct targeted therapy. Decide again.
If there is a genetic mutation, is there definitely a targeted drug available?
No. There are too many types of gene mutations. The vast majority of gene mutations are currently unclear whether they are related to tumors; most of them can identify gene mutations that are related to tumors (such as P53 mutation, KRAS mutation, MYC amplification, etc.). Targeted drugs already on the market. Therefore, some patients have detected genetic mutations, but there are still no suitable targeted drugs available on the market.
The consequences of "blind eating" targeted drugs
Without genetic testing, blindly using targeted drugs will not only increase the financial burden of patients, but also more likely to miss the time for optimal treatment. Once the targeted drug is misused, it will delay treatment and accelerate the deterioration of the disease.
In general, the genetic testing cycle is about 7-10 working days. After the operation, the patient also needs about two weeks to wait for the body to recover before proceeding to the next treatment. Therefore, this period of time can be fully used to wait for the test results. By conducting genetic testing as soon as possible, treatment plans can be formulated as soon as possible and applied in clinical treatment in a timely manner.
Are the side effects of targeted drugs large?
Compared with chemotherapy, targeted therapy is milder and has fewer side effects. Some patients can show rash and diarrhea in a short period of time, usually symptomatic treatment.
What if the targeted drugs become resistant?
The root cause of drug resistance is that the tumor has generated new genetic mutations, and it is best to conduct genetic testing again. If the patient's physical condition is not suitable for surgery or puncture, peripheral blood can be used as a substitute to detect circulating tumor DNA (ctDNA) in the blood.
It is recommended that the tissue and blood be tested together at the first test to obtain the most complete information and provide patients with effective personalized treatment to the greatest extent.
What should be paid attention to when storing targeted drugs?
Most targeted drugs require shading, closed storage, and storage in strict accordance with the storage conditions on the instructions. After opening the medicine jar, throw away the cotton or desiccant and take the medicine within the validity period.
