Lung Cancer Diagnosis: Why Biomarker Testing Matters Before Treatment

For many patients who have received a lung cancer diagnosis, the immediate instinct is to start treatment and move fast.

But experts in lung cancer care say that urgency, while completely understandable, can sometimes lead patients away from the very treatment that would work best for them. Before any treatment decision is made, there is one step that should come first: comprehensive biomarker testing.

Not All Lung Cancers Are the Same

One of the most important shifts in oncology over the past two decades is the understanding that lung cancer is not a single disease. It is many diseases, each driven by different changes in the genes of the tumor. Some of those gene changes — called mutations or fusions — can be directly targeted by treatments designed specifically to block them.

"Not all lung cancers are the same," said Dr. Eric Singhi, a thoracic medical oncologist at The University of Texas MD Anderson Cancer Center. "Some are driven by specific changes in the genes of the tumor, changes we can now test for, should be testing for, and in many cases directly target with drugs designed to block them."

Knowing which gene change, if any, is driving a patient's cancer can completely change the treatment plan — and potentially the outcome.

A Patient's Story: The Wait That Changed Everything

Leah Phillips was 43 years old, healthy, and raising three small children when she was diagnosed with stage 4 lung cancer. The experience of waiting for biomarker test results — results that would reveal whether her cancer had a targetable gene change — is something she describes vividly. "I remember sitting on the floor... cancer is in my body, and I'm not doing anything to stop it," Phillips said. "And I know it. It was shocking."

Her community oncologist had already told the family they would start chemotherapy and immunotherapy before the biomarker results were back. It was only through a connection to Vanderbilt's thoracic department that her family learned that doing so could be harmful if her tumor turned out to have a targetable mutation. So, she called off the treatment appointment. On Dec. 30, the results came back: Phillips had an EGFR exon 19 mutation, one of several targetable alterations in lung cancer. That finding opened the door to a targeted therapy that has kept her cancer controlled for more than six years.

"That cancer didn't just pop up 14 days ago. Nobody can tell you how long it's been there, but in the big scheme of things, these 14 days, if you can distract yourself and get yourself in order, could save your life," said Phillips.

The Wait for Biomarker Testing — and Why It Matters

For patients waiting on biomarker results, the timeline — often 10 to 14 days for comprehensive next-generation sequencing — can feel unbearable. As a result, Phillips now uses her own story to help newly diagnosed patients understand what to do with that time.

"Instead of thinking of this as sitting here doing nothing, think about how you can do things to prepare," she tells patients. That means making a list of questions for the care team, asking about scan schedules, finding out about advocacy groups, learning how to use patient portals, and making sure all recommended imaging — including a brain MRI — has been completed.

Lisa Spain, executive director of Rexana's Foundation and a 20-year lung cancer advocate, echoes that message. She founded the organization after losing her closest friend to lung cancer 60 days after diagnosis, at a time when options were limited and targeted therapy was not yet a reality.