Does a negative lung cancer gene test mean that targeted drugs must be ineffective, but this is not the case

A patient asked: "My father suffered from brain cancer when he underwent genetic testing. The mutation rate was 10%, which is too low. Doctors do not recommend using targeted drugs, but there are many patients who do not have gene mutations or are as effective as blind eating." How do doctors judge whether targeted drugs can be used?

Non-small cell lung adenocarcinoma in lung cancer has a higher probability of EGFR gene mutation, and EGFR gene mutation can use TKI targeted drugs Iressa, Tarceva or Conmana. Now there are second- and third-generation targeted drugs, such as afatinib and osimertinib. As far as lung cancer is concerned, genetic testing must be done before taking small-molecule TKI targeted drugs. The so-called targeting must have a suitable target to play a role. If the mutation abundance of genetic testing is too low, oral targeted Drug efficacy is very poor. Everyone knows that targeted drugs are very expensive because they have not been around for a long time. If they are taken blindly or by people who are negative for gene mutations, it will not only waste a lot of money, but may also delay the disease. There are indeed some patients who eat blindly. After all, the mutation rate of EGFR gene in Chinese is relatively high, especially for non-smoking female lung adenocarcinoma patients, the mutation rate reaches 50%. .

There are indeed patients with negative gene mutations and effective oral targeted drugs, but the probability is relatively low. Sometimes one or two patients are encountered clinically, and it feels a bit like winning a lottery, a low-probability event. There are many reasons for this. 1. It may be that the detection is inaccurate. Now there are so many genetic testing companies, good and bad, and there is a big difference in technology. In comparison, the accuracy of postoperative specimen testing is higher than that of genetic testing companies. Blood samples, and some patients cannot obtain samples or use blood samples for testing to save trouble. At this time, false negative results may appear. False negative means that there is an EGFR gene mutation, but it was not detected. 2. There is no mutation in the EGFR gene, but there is high expression of EGFR protein, that is, the amount of EGFR protein increases, which drives the occurrence of tumors. At this time, the use of targeted drugs such as small molecule tyrosinase inhibitors is also effective. 3. There is another situation, which is also a relatively high incidence. The specimens obtained when we do tumor diagnosis generally only account for a small part of the tumor (especially lung puncture). This small part may not have mutations, but the remaining The lower part of the tumor has a genetic mutation.

Therefore, under normal circumstances, doctors definitely recommend that patients do genetic testing before using targeted drugs. If necessary, multiple testing can be done to improve accuracy. It is best to provide tissue samples, such as postoperative tumor tissue samples, lung puncture samples, and pleural effusion exfoliated cell samples. Patients who cannot provide samples can draw blood for testing. Patients with mutations in genetic testing are recommended to take targeted drugs orally. If the test is negative, there is really no other treatment, and the economic conditions are better. After in-depth communication, you can also try targeted drugs.

Nowadays, new targeted drugs are emerging in an endless stream. For example, anlotinib can effectively inhibit VEGFR, PDGFR, FGFR, c-Kit and other kinases, and has the effect of anti-tumor angiogenesis and inhibition of tumor growth. This drug does not require genetic testing and is currently included in cancer treatment guidelines as a third-line drug for lung cancer. Apatinib targets c-kit, Ret and c-Src, etc., mainly VEGFR-2, which inhibits VEGF binding to it and autophosphorylation, thereby inhibiting angiogenesis, which has also been shown in many clinical studies of lung cancer. In terms of curative effect, this drug is mainly anti-tumor angiogenesis, and genetic testing is also not required.