In the past two days, a classmate from Shandong asked me for advice. His father had just undergone laparoscopic surgery for pulmonary nodules. On the day of the surgery, the doctor asked the family if they wanted to do genetic testing. The cost is relatively high. This classmate thought of asking me for the first time, is this genetic test necessary? I answered him, at least we have to wait for the major pathology of the surgery to come out, and then decide based on the postoperative pathological conditions and staging. After all, more than 10,000 yuan is not a small amount. A week later, the pathological result was carcinoma in situ. I explicitly told him that genetic testing was not required.
It’s true that many people don’t know what genetic testing is for and whether to do it or not. Many people think that since the doctor has suggested it, it is better to do it than not to do it well, and spend money to buy peace of mind. The purpose of genetic testing is to determine whether the corresponding targeted drugs can be used, to determine the effect of immune drugs, and to determine the prognosis of patients. Of course, the more items, the more expensive, and the more information they provide. But in fact, not all lung cancer patients need genetic testing. For example, my classmate’s father, with lung cancer in situ, has a 100% cure rate and does not require any postoperative treatment, so there is no need for genetic testing.
In terms of staging, stage 0 carcinoma in situ and stage IA minimally invasive carcinoma are 100% cured, and no genetic testing is required. Patients with stage IA do not need any adjuvant therapy, including targeted therapy, after surgery according to the guidelines for the diagnosis and treatment of lung cancer. In theory, there is no need for genetic testing. However, in stage IA, especially in stage IA3 with many high-risk factors, some patients may have recurrence and metastasis in the following years. For such patients, genetic testing can be done according to the wishes of their families. On the one hand, patients use targeted drugs according to their own wishes and detection conditions. On the other hand, it is difficult for some patients to obtain specimens from biopsy after recurrence and metastasis. Genetic testing in advance can also guide the use of targeted drugs in future recurrence and metastasis.
For lung adenocarcinoma patients with stage IB and above, genetic testing is routinely performed, because adenocarcinoma patients in my country have a relatively high mutation rate of sensitive genes, and there is a greater chance of using targeted drugs. It was also updated last year, recommending adjuvant targeted therapy for patients with IB and above after surgery, and osimertinib is preferred for patients with positive EGFR mutations.
Therefore, for patients with adenocarcinoma in the major postoperative pathology, and patients with stage IB and above routinely need to do genetic testing, and patients with squamous cell carcinoma in the major pathology after radical resection, 12 targets may not be used. However, it is recommended to perform immunotherapy-related indicators such as PDL1, TMB, MSI, etc., to guide subsequent immunotherapy.
For patients with advanced lung cancer, if it is a small specimen obtained by puncture or bronchoscopy, genetic testing must be done to diagnose adenocarcinoma. For squamous cell carcinoma or small cell lung cancer, genetic testing can be considered depending on the economic situation. Because the small sample tissue is too small, it may not reflect the state of the overall tumor tissue. For example, some mixed tumors have both squamous cell carcinoma and adenocarcinoma components, or small cell carcinoma components. The tissue taken at this time may not be completely covered. The true type of tumor. If adenocarcinoma is combined, it may also benefit from targeted drugs.
Since squamous cell carcinoma is relatively effective in immunotherapy, patients with advanced squamous cell carcinoma are recommended to target immunotherapy-related targets, because if PDL1 is highly expressed (PDL1>49%), single-drug immunotherapy will not be effective. can play a very good role.
In terms of the selection of genetic testing methods, if it is a large postoperative specimen, the first-generation ARMS method can be selected, covering 10-15 genes, and the price is low. For advanced patients, because it is difficult to repeatedly obtain materials, it is recommended to choose the second-generation NGS test, which can detect many genes at one time, but the price is expensive. In addition, blood drawing, pleural and ascites exfoliated cells can also be tested by NGS, and this method can also be considered for patients who cannot obtain specimens.