The Importance of PD-L1 Testing
- If you have non-small cell lung cancer (NSCLC), your doctor will recommend PD-L1 testing. This test will help your doctor understand if you can be treated with a type of cancer drug called immune checkpoint inhibitors.
- About a third of patients with late-stage NSCLC have high levels of PD-L1 and can potentially benefit from immunotherapy.
- If your cancer has certain genetic mutations, immune therapy may still work, but targeted therapy will be recommended first.
The Importance of PD-L1 Testing – At a Glance
- If you have non-small cell lung cancer (NSCLC), your doctor will recommend PD-L1 testing. This test will help your doctor understand if you can be treated with a type of cancer drug called immune checkpoint inhibitors.
- About a third of patients with late-stage non-small cell lung cancer (NSCLC) have high levels of PD-L1 and can potentially benefit from a treatment option called immunotherapy.
- If your cancer has certain genetic mutations, immune therapy may still work, but targeted therapy will be recommended first and foremost.
- It is OK to discuss PD-L1 testing as well as genetic mutation testing with your oncologist and/or healthcare team to ensure you are your biggest advocate for better health.
PD-1, referred to as programmed cell death 1, is a protein that is found on the outer surface of cells in your immune system. PD-L1, referred to as programmed cell death ligand, is on the outer layer of some normal blood cells, as well as some cancer cells. When PD-1 binds to PD-L1, this puts the brakes on the immune system and can prevent immune cells from attacking and killing cells. Normally, this acts as a braking mechanism to prevent our immune systems from becoming overactive and going somewhat haywire by attacking our normal cells. Cancer cells can take over or override this innate mechanism, preventing cancer cells from dying.
Fast Facts: Lung Cancer
- Lung cancer is the second most common form of cancer and the leading cause of cancer deaths in both men and women in the United States.
- Smoking is, of course, the primary cause of lung cancer, but non-smokers can and do develop this disease.
- The good news is that if you quit smoking, your risk for lung cancer decreases.
- There are several surgeries for lung cancer, and the decision about which is best is based on the location of your cancer, its size, and whether it has spread.
PD-L1 Testing Guidelines – Know the Basics
This type of test is used to ensure specific therapies are used during treatment that targets the PDL/PD-L1 interaction. This type of testing is performed for patients with lung cancer. Still, it can also be utilized when a patient has any of the following other cancer types: melanoma, Hodgkin lymphoma, bladder, breast, or kidney. Researchers are looking for new cancers that may benefit from immunotherapy every day and are hopeful that this list will expand in the future. A biopsy is used to remove a sample of cells (or, in some cases, fluid) of the cancerous tumor for testing PD-L1 levels. The three standard biopsy procedures are fine needle, surgical, and core needle. The certain type of procedure depends on practitioner preference, tumor characteristics, and patient age. Biopsies are relatively routine and minimally invasive procedures. Although it may be nerve-racking to undergo any procedure, it is of utmost importance to do so to make informed treatment options.What are the risks?
Common risks or side effects of a biopsy procedure that is used to obtain cancer cells for evaluation and analysis include localized tenderness, bleeding, and bruising at the procedure site. There is also a risk of infection after the procedure is complete. Your physician may provide you with a prophylactic antibiotic in the event this occurs. Patients with a history of frequent infections or certain medical issues are more likely to get a prophylactic antibiotic than the general population. A surgical biopsy is a more initiative procedure, which may cause additional discomfort or pain to the patient.Preparing for the Procedure – What to Know
Your oncologist and healthcare team should provide you with detailed instructions regarding proper preparation for your biopsy. Some procedures only require the use of a local anesthetic. If this is the case, no specific preparation is required. However, fasting will likely be needed if anesthesia is required to obtain a sample of the cancerous cells. It is very common to feel uneasy and anxious prior to any procedure, let alone a biopsy. If this is the case, your physician may provide you with a prescription for an anti-anxiety medication to be used prior to the procedure. This will help you “shake off the nerves” and relax in time for the procedure.
PD-L1 Testing Results – What Does it All Mean?
This test will provide you with the level of PD-L1 in your cancerous tumor cells. This will typically be recorded in a percentage. A high level of PD-L1 is a good indication that certain immunotherapy treatment options will be effective for you. On the other hand, if test results show a low level of PD-L, you may not be a candidate for certain treatment options which target this specific (PD-1/PD-L1) pathway. Regardless of the results, this testing is essential for making the best decisions possible in your journey of fighting cancer.
If Your PD-L1 Is Greater than 50%
“The PD-L1 test allows you to understand if the patient will benefit from immunotherapy alone or if for the patient we need chemo,” explains Dr. Narjust Duma, a thoracic oncologist at Dana-Farber Cancer Institute, “If their PDL1 is higher than fifty percent, the patient can undergo only immunotherapy and skip the chemo. There are several caveats to that, but that is the general knowledge.”
Suppose you have NSCLC that has spread (metastatic), and your PD-L1 is greater than fifty percent. In that case, three types of immunotherapy can be used, which include the following medications: pembrolizumab (Keytruda®), atezolizumab (Tecentriq®), and cemiplimab (Libtayo®).
Of note, these pharmacological agents have not previously been compared to each other. In addition, PD-1/PD-L1 blockers alone have not been compared in a clinical trial to PD-1/PD-L1 blockers combined with chemotherapy. In most patients, immunotherapy can be started as first-line treatment. If the cancer progresses while on immunotherapy, you can receive chemotherapy when and if you need it. However, you may be recommended for immunotherapy plus chemotherapy if your cancer shows signs of aggressive or rapid progression.
But many people with higher PD-L1 expression show prolonged immunotherapy responses, “Some patients with PDL1 are living years and some patients are being taken off therapy for a while because the response is so long, and when the tumor grows, they go back on it,” Dr. Duma says.
If Your PD-L1 is Less Than 50%
If your PD-L1 expression is less than 50 percent, the standard treatment is chemotherapy and pembrolizumab (Keytruda®) (for squamous and non-squamous non-small cell lung cancer). Chemotherapy with bevacizumab (Avastin®) and atezolizumab (Tecentriq®) is an approved alternative (IMpower 150 trial) for non-squamous only. Immunotherapy can be used as monotherapy for patients who cannot have chemotherapy.
Immunotherapy is used as a first-line treatment in patients who do not have lung cancer driver mutations, such as EGFR or ALK. However, it may be used if cancer progresses while on agents that target these specific mutations.
Will Immunotherapy Work for My Lung Cancer?
About a third of patients with advanced-stage NSCLC have high levels of PD-L1 and can potentially benefit from immunotherapy:
- The Keynote 024 trial for patients with late-stage NSCLC and a PD-L1 score of at least fifty percent showed an overall survival of 26.3 months in patients who received pembrolizumab (Keytruda®), compared to 13.4 months in a patient who received chemotherapy treatment.
- Progression-free survival was 24.1 months in the pembrolizumab group, compared to 8.5 months in the chemotherapy group.
Thus, for many patients, PD-L1 drugs can provide a meaningful improvement in survival. If your cancer has specific mutations, immune therapy may still work, but targeted therapy will be recommended first.
Questions to Ask Your Doctor – Moving Forward
- Does my cancer have a target mutation? If so, which one?
- Am I eligible for targeted therapy?
- Have you checked my cancer’s PD-L1 status?
- Does my PD-L1 status enable me to use immunotherapy?
- If my PD-L1 status does not support the use of immunotherapy, what other drugs or therapies can I use?
Be Your Own Advocate
It is important that YOU are your biggest advocate when it comes to all aspects of healthcare, especially during cancer diagnosis and treatment. It is of utmost importance to stay informed on current treatments and diagnostic standards as well as new therapies coming down the pipeline. It is OK to ask your practitioner and your clinical care team about laboratory testing, like PD-L1. Doing so will ensure all your bases are covered when it comes time to create the best treatment action plan possible to prolong survival, improve quality of life, and hopefully conquer your cancer journey. Stay informed and participate actively in your healthcare as you are in the driver’s seat accompanied by your oncology team.
Final Thoughts
Undergoing numerous laboratory tests may seem daunting at times as well as cumbersome. However, testing for PD-L1 levels and genetic mutations will ensure the best possible treatment options are used to treat your specific cancer type. Not all cancer types are made equal. That said, treatment action plans must be individualized based on information gathered through diagnostics and other laboratory tests. It is essential to stay educated and understand all aspects of your cancer journey. Doing so will keep you on track to better health.
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