What you need to know about genetic testing for lung cancer

The article is written by Master, Doctor Mai Vien Phuong - Gastroenterologist - Department of Medical Examination & Internal Medicine - Vinmec Central Park International General Hospital.

Non-small cell lung cancer (NSCLC) is the term for a condition caused by more than one genetic mutation in the lungs. Testing for these different mutations can influence treatment decisions and outcomes. Follow the article below to learn about the different types of NSCLC, the tests and treatments available.

The biggest risk factor for lung cancer is smoking. Includes cigarettes, cigars and pipes. Tobacco products contain thousands of harmful substances.
According to the Centers for Disease Control and Prevention (CDC), smokers are 15 to 30 times more likely to develop lung cancer than non-smokers. The longer you smoke, the greater your chances of getting lung cancer. Quitting smoking can reduce that risk.
Secondhand smoke inhalation is also a major risk factor. Each year in the United States, about 7,300 people who have never smoked die from lung cancer from breathing secondhand smoke.
Exposure to radon gas, a natural gas also increases the risk of lung cancer. Radon rises from the ground, entering buildings through small cracks. It is the leading cause of lung cancer in non-smokers.
Your risk of developing lung cancer is also higher if you are exposed to harmful substances such as asbestos or diesel exhaust in the workplace.
Other risk factors include:
Family history of lung cancer. Personal history of lung cancer, especially if you are a smoker. Had radiation therapy to the chest.

Gene mutations, whether inherited or not, contribute to the development of cancer. Many mutations associated with NSCLC have been identified. This helps researchers develop drugs that target some of those specific mutations.
Understanding which mutations are causing the cancer can help doctors see how the cancer will progress. This can help determine which medications are most likely to work and which aren't.
That's why genetic testing after a diagnosis of NSCLC is so important. It helps personalize your treatment. Targeted treatments for NSCLC are continuing to increase. We can expect to see more progress as researchers discover more about the specific genetic mutations that lead to NSCLC progression.

There are two main types of lung cancer: small cell lung cancer and non-small cell lung cancer. About 80 to 85% of all lung cancers are NSCLC, which can be divided into the following subtypes:
Adenocarcinoma : Starts in young cells that secrete mucus. This type is usually found in the outer parts of the lungs. It tends to occur more often in women than men and in younger people. In general, this is a slow-growing cancer that is easier to detect in its early stages. Squamous cell carcinoma: Starts in the flat cells that line the inside of the air passages in your lungs. This type is likely to start near the main airway in the middle of the lungs. Large cell carcinoma: Can start anywhere in the lung and can be very malignant. Once you know what type of NSCLC you have, the next step is often to identify the specific genetic mutations that may be involved.

At the initial biopsy step, the pathologist is checking for the presence of cancer. The same tissue sample from your biopsy is often used for genetic testing. Genetic tests can screen for hundreds of mutations.
These are some of the most common mutations in NSCLC:
EGFR mutations occur in about 10% of people with NSCLC. About half of people with NSCLC who have never smoked are found to have this gene mutation. EGFR T790M is a variant of the EGFR protein. KRAS mutations are involved in about 25% of cases. The ALK/EML4-ALK mutation is found in about 5% of people with NSCLC. It tends to involve younger people and non-smokers or light smokers with adenocarcinoma. Less common genetic mutations associated with NSCLC include:
BRAF. HER2 (ERBB2). MEK. MET. RET. ROS1.

There are different treatments for NSCLC. Since not all NSCLCs are the same, treatment must be carefully considered.
Detailed molecular tests can tell you, whether your tumor has a specific gene or protein mutation. Targeted therapies are designed to treat specific features of the tumor.
Here are some targeted therapies for NSCLC:
EGFR EGFR inhibitors block signaling from the growth-promoting EGFR gene. Includes:
Afatinib (Gilotrif). Erlotinib (Tarceva). Gefitinib (Iressa). These are all drugs. For advanced NSCLC, these drugs may be used alone or in combination with chemotherapy. When chemotherapy doesn't work, these drugs can still be used even if you don't have the EGFR mutation.
Necitumumab (Portrazza) is another EGFR inhibitor used for severe squamous cell NSCLC. It is given through an intravenous (IV) line in combination with chemotherapy.
EGFR T790M EGFR inhibitors help shrink tumors, but these drugs may wear off at some point. The doctor may then order an additional tumor biopsy to see if the EGFR gene has developed another mutation called T790M.
In 2017, the US Food and Drug Administration (FDA) approved the drug osimertinib (Tagrisso). This drug treats severe NSCLC associated with the T790M mutation. Treatment is indicated when EGFR inhibitors do not work.
ALK/EML4-ALK Therapies that target the abnormal ALK protein include:
Alectinib (Alecensa). Brigatinib (Alunbrig). Ceritinib (Zykadia). Crizotinib (Xalkori). These oral medications may be used in place of chemotherapy or after chemotherapy has worn off.
Other targeted therapies include:
BRAF: Dabrafenib (Tafinlar). MEK: Trametinib (Mekinist). ROS1: Crizotinib (Xalkori). Currently, there is no approved targeted therapy for the KRAS mutation but studies are ongoing.
Tumors need to form new blood vessels to keep growing. Your doctor may prescribe therapy to stop new blood vessel growth in severe NSCLC, such as:
Bevacizumab (Avastin), which may be used with or without chemotherapy. Ramucirumab (Cyramza), which can be combined with chemotherapy and is usually given after other treatments have stopped working. Other treatments for NSCLC may include:
Surgery. Chemotherapy. Radiation. Palliative therapy to relieve symptoms. Clinical trials are a way to test the safety and effectiveness of experimental therapies that have not been approved for use. Talk to your doctor if you want to learn more about clinical trials for NSCLC.
When there are suspected signs of lung cancer, you can go to Vinmec International General Hospital for examination and treatment. Vinmec provides a full range of necessary medical care services for cancer patients including: Chemotherapy, radiation therapy, surgical treatment, medical treatment, stem cell transplant,...; At the same time, helping to control pain by physiotherapy, peripheral nerve block, sympathomimetic block,...
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