You may hear genetic testing referred to by other terms, such as biomarker testing, mutation testing, genomic testing, or molecular testing. But what does this all mean? And why should you talk to your doctor about it? Each cell in your body contains chromosomes, which are made up of thousands of genes that control how the cell functions. Mutations in the DNA of these genes can affect how cells grow and divide. Some mutations activate the cell to continue growing, even if it shouldn’t. Others interfere with processes that slow down cell division or tell cells to die, which can also lead to out-of-control cell growth. “These cells can ultimately become aggressive and start growing irrationally, and that’s what causes cancer — and causes it to spread,” says Dr. Adusumilli. Genetic mutations can be inherited, but most are acquired during your lifetime through exposure to cancer-causing compounds, such as cigarette smoke, air pollution, or radon. Some mutations occur randomly and have no known cause. Genetic testing looks for acquired mutations, which affect only the cells that grow from a mutated cell, unlike inherited mutations, which affect every cell in your body — both cancer cells and healthy ones. Your tumor tissue or blood sample is sent to a lab, where it is analyzed for biomarkers such as DNA mutations or levels of specific proteins in the genes that may be causing your tumor or driving its behavior. Comprehensive genetic testing looks for a large number of mutations, such as those on EGFR, ALK, BRAF, ROS1, and NTRK genes. This analysis provides doctors with a genetic profile of your tumor and gives them a better understanding of how your condition may change over time — and what the most effective course of treatment may be. Results will show if your tumor has any mutations that can be treated with an FDA-approved targeted therapy, or if it has any mutations with therapies currently being studied in clinical trials. Even if you don’t have mutations that are currently treatable with targeted therapies, the results of your genetic test can still affect treatment decisions and outcomes, including whether your cancer is likely to return. If you are prescribed a targeted therapy but eventually develop a resistance to it, or you go through treatment and later experience a relapse, your doctor may suggest additional genetic testing to find out if your tumor has developed a new mutation. Second- and third-line therapies are increasingly becoming available to treat such cases. Genetic testing can also reveal information about other potential complications, such as an elevated risk for heart attack, which may impact your treatment plan. Targeted therapies directly target gene mutations to stop or slow lung cancer growth while also limiting damage to healthy cells. Although only about 15 percent of known mutations associated with lung cancer currently have targeted therapies, the drugs that are available to treat these mutations have proven to be highly successful, resulting in better clinical outcomes and improved overall survival rates for people with locally advanced and metastatic NSCLC. Targeted therapy drugs are designed to interact with a specific molecular target. They typically work by either blocking signals that tell NSCLC cells to grow and spread, shrinking tumors, or disabling certain proteins. Some, such as angiogenesis inhibitors, block tumor blood vessel growth, which in turn suppresses tumor growth. There are currently FDA-approved targeted therapies for mutations found in EGFR, ALK, ROS1, BRAF, and NTRK genes. When creating a treatment plan, your doctor will consider your diagnosis, your overall health and wellness, and any risk factors or other complicating factors, along with your personal preferences for treatment. Your doctor may recommend: Surgery to remove the lung tumor. Your doctor may also want to remove one of the lung’s five lobes, a portion of the lobe, or the entire afflicted lung. Chemotherapy drugs to kill cancer cells by preventing them from growing and dividing. Because they travel throughout the body, these drugs may also affect healthy cells. Radiation therapy, which typically involves using an external-beam x-ray machine to destroy cancer cells. Immunotherapy to help reactivate the body’s immune system and its natural defenses against the cancer. This therapy is increasingly being used in conjunction with targeted therapy drugs, and Adusumilli believes that the combination of these two therapies is going to drive the NSCLC treatment field over the next five years. Palliative care to relieve symptoms and treatment side effects and to address your emotional needs. This option may include pain medications, interventions to treat fluid buildup around the lungs or heart, supplemental oxygen, and other treatments to improve quality of life. Everyone with metastatic NSCLC should talk to their doctor about having their tumor tested for mutations. If your doctor doesn’t bring it up, ask if you may be a good candidate for genetic testing. Here are some key questions to get the conversation started: Images: iStock
