Importance of Biomarker Testing in NSCLC


Paul K. Paik, MD, reviews the importance of biomarker testing and best practices in testing in patients with non-small cell lung cancer.

Briana Contreras: Welcome to this Managed Healthcare Executive® program titled “Advances in Biomarker-Driven Therapy for Advanced NSCLC [non–small cell lung cancer].” I’m Briana Contreras, an associate editor of Managed Healthcare Executive®. Joining us today is Dr Paul Paik, the clinical director of thoracic oncology service at Memorial Sloan Kettering Cancer Center in New York[, New York]. In today’s discussion, Dr Paik and I will focus on the targeted therapy treatment landscape for non–small cell lung cancer. Let’s get started.

Dr Paik, first, we would like to review the importance of biomarker testing for patients with non–small cell lung cancer and the best practices for testing. The first question I want to ask: Why is biomarker testing important for patients with non–small cell lung cancer?

Paul K. Paik, MD: Biomarker testing is important in the treatment of patients with non–small cell lung cancers because there are many therapies that we now have that are linked to finding these biomarkers in our patients. This really has become standard of care to the point where we now have 7 biomarkers with multiple approved therapies. It’s quite important to do this testing to find the right treatments for our patients.

Briana Contreras: What percentage of patients with advanced non–small cell lung cancer have targetable mutations? What do we know about their response to the standard of care like, for example, nontargeted therapies?

Paul K. Paik, MD: The number of patients with targetable mutations varies depending on how you define targetable, whether this is with FDA-approved treatments or, increasingly, treatments that are in development in clinical trials where there has been a good signal—where we will likely get an approval, but where 1 does not exist yet. Probably more than 75% of patients, or 3 of 4, have a targetable mutation that’s found at the beginning, or that we will find in time. As to what the response these patients will have to our standard of care, that depends. Some of the standard of care is the targeted therapy, and that’s the important point behind testing. The responses in general to these targeted therapies for folks who have these biomarkers present is very high, and it exceeds what we have seen with standard chemotherapy, for example, or even chemo-immunotherapy.

Briana Contreras: Can a patient with non–small cell lung cancer have more than 1 biomarker?

Paul K. Paik, MD: In general, patients with non–small cell lung cancers who do have these alterations, these biomarkers, have 1 at the time of diagnosis. This gets at the biology, where that biomarker, that alteration is so important that that’s all the cancer cell needs to grow and divide. A good example would be patients who have EGFR mutations, for example. We consider this mutually exclusive of other biomarkers or genetic alterations that we find. This story gets a bit more complicated when patients progress on targeted therapies—where we can find more than 1—but that gets into the land of some additional subtlety, which we can go over later.

Briana Contreras: Thank you. When and for whom do you test for biomarkers? Should every patient with non–small cell lung cancer be tested? If so, when?

Paul K. Paik, MD: That’s a great question. Basically, everyone with non–small cell lung cancers should be tested for different biomarkers. This includes patients with lung adenocarcinoma, squamous cell lung cancers, and poorly differentiated cancers. The reason is because we’ve come to understand that a low frequency can be found in anyone who has non–small cell lung cancer. Even at low frequency, because there are so many patients diagnosed with lung cancer, that ends up being a lot of patients. Of course, for the individual patient it is a 9-day finding if we do end up identifying a biomarker, so for that individual patient it’s incredibly important. Because these things can make such a dramatic difference in outcomes for patients, we recommend that patients get the testing done as soon as possible at the time of diagnosis.

Briana Contreras:Do you always use NGS [next generation sequencing] testing? Why or why not?

Paul K. Paik, MD: That’s a great question. At the end of the day, we always use NGS testing because it’s the most comprehensive. There are many biomarkers at this point that we need to test for, and doing this on a single-test basis is slow. It’s also wasteful because these biopsies that we get for patients with lung cancer end up being small-needle biopsies most of the time, and there’s not a lot of material in these samples. Everyone eventually gets NGS testing because some institutions and some pathology departments do stage testing. They will test using a faster turnaround time assay for some of these more common alterations, which we know are mutually exclusive, to get that information as fast as possible for patients, and then we’ll go on to NGS testing afterward if those initial assays are negative.

Briana Contreras: Do you always use tissue when testing for biomarkers? Or do you sometimes use ctDNA [circulating tumor DNA]? If you use ctDNA, when do you do so?

Paul K. Paik, MD: Tissue testing for these biomarkers is the gold standard, and it’s the gold standard in part because there’s a lot of material that is present in these samples, particularly the DNA and RNA used for testing. From that standpoint, it’s going to be the most sensitive for test results. We use ctDNA testing as a companion to tissue testing in part because the tissue biopsies are invasive. Often, these are lung biopsies, so there’s risk associated with the procedure, and sometimes that risk is too high for a given patient—ctDNA testing is through the blood, and that’s not terribly invasive for most patients. The other reason we use ctDNA testing is because the turnaround time is still faster than tissue testing, so some of these assays will get results back within 5 to 7 business days. Because finding these biomarkers at the beginning is so important, a lot of doctors are using this earlier to find these alterations.

Transcript edited for clarity.

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