Biomarker Testing in Lung Cancer Continues to Improve Outcomes, Move the Field Forward

Treating lung cancer is more precise than ever, thanks to biomarker testing, which gives clinicians a better understanding of individual’s tumors.

Years ago, many patients with lung cancer were treated the same, as there was limited knowledge about the disease and limited therapies to treat it. Then, biomarker testing brought precision medicine into the world of lung cancer, and now patients are treated with drugs specifically designed to treat cancer with certain characteristics.

“When we think about precision medicine in cancer treatment, we think about unique therapies that treat an individual’s cancer that are based on the biomarkers of that person’s cancer,” said Elisabeth M. King, the executive director of Genomics and Precision Medicine at City of Hope.

Biomarkers are the proteins, genes and other molecules that usually are caused by genetic changes that affect how cancer cells grow, multiply, die and respond to drugs in the body. King explained the importance of biomarkers in CURE®’s recent Educated Patient® Lung Cancer Summit.

“All patients are different; all cancers are different,” she said. “And even when you think about lung cancers, all lung cancers are different. And we can really use this (biomarker) information to determine the exact drugs or treatments that have the best chance of working for that individual patient’s specific cancer.”

Biomarker Testing Processes

There are a few ways that patients can undergo biomarker testing.

They can have direct sampling of tumor tissue, where a small part of the actual tumor is taken out and tested. King referred to this as the “gold standard” of biomarker testing. This gives clinicians important pathological information, as well as biomarker information that may be specific to the tumor and not found in the person’s DNA.

But on the downside, this method tends to have a longer turnaround time, is more invasive and some patients may have barriers to accessing it.

Patients can also undergo a liquid biopsy, which is a less-invasive procedure, and is similar to a blood test. Liquid biopsies are more readily available and have a quicker turnover time than tumor testing, though the same cost and access barriers remain, and through this method, clinicians cannot get access to non-DNA (tumor-specific) biomarkers.

Who Should Be Tested, and Why?

Current recommendations are that patients with stage 1 through 3 squamous cell lung cancer only undergo biomarker testing for clinical trial purposes. At stage 4, patients may be tested for PD-L1 to determine if they will benefit from checkpoint blockade immunotherapy agents. These patients may also be tested for EGFR or ALK mutations if their doctor thinks that the tumor may have adenocarcinoma cells.

Patients with adenocarcinoma at stage 1 through 3 should be tested for EGFR, ALK, KRAS, ROS1 and BRAF V600E mutations as well as PD-L1 protein levels. This typically happens if the doctor deems it appropriate or if the patient is not eligible for surgery. Patients with stage 4 adenocarcinoma should undergo all of the aforementioned testing.

While biomarker testing is currently underutilized, it can lead to major implications in treatment decision making. King mentioned a study of nearly 10,000 patients with lung cancer who were tested for EGFR, ALK, ROS1, BRAF and NTRK mutations, as well as PD-L1 status. Nearly all of them were found to have biomarkers that have available therapies or clinical trials testing treatments that target certain tumor characteristics.

“What they found was that 96% of these patients were eligible for biomarker-associated therapies in clinical trial enrollment,” King said.

Looking ahead, King commented that she is optimistic about the continued development of precision medicine in the field of lung cancer. In fact, she noted that there are currently thousands of clinical trials geared toward doing just that.

“This is the direction that lung cancer treatment is going and continues to go, which is really exciting because we know if these treatments work better, they have fewer side effects,” King said. “We don’t want to hit the lung cancer with a hammer. We want to use more targeted therapy.”

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