In this third part of the Hope With Answers Targeted Therapy series, learn more about acquired resistance to targeted therapy in lung cancer treatments. Janet Freeman Daily chat with Dr. Christine Lovly of Vanderbilt-Ingram Cancer Center to discuss the ways tumors can become resistant, and how there are now more treatments than just chemotherapy. In addition, she explains liquid biopsies and why they’re such an impact on lung cancer diagnosis and treatment.
What is Acquired Resistance to Targeted Therapy?
Acquired resistance means that tumors can find ways to get around these TKI drugs (tyrosine kinase inhibitors) and stop responding to treatments. Two ways that the cancer gets around the drugs:
- There’s a mutation or a change in the DNA of the tumor that keeps the targeted therapy drug from binding to the protein the way it did before.
- Tumors learn a way around the roadblock set up by the current targeted therapy. The cancer finds alternative routes – a way to get to the same endpoint which is to grow and not listen to the body’s normal checks and balances.
What Can You Do If Your Lung Cancer Targeted Therapy Stops Working?
Dr. Lovly’s advice when acquired resistance happens is “This is gonna be something where a patient wants to really talk to their doctor very closely to figure out what is the next step. And it can be very different depending on what markers in your tumor. We can treat it with another TKI that would be based on additional biomarker testing. So we wanna make sure that we’re bringing the precision to our next line of treatment, but that the actual drug that comes next is gonna depend on what the initial target was and then what the mechanism of resistance is.”
Liquid Biopsy Testing for a Different Targeted Therapy
Liquid biopsy may be used instead of the more invasive biopsy of the tumor. A liquid biopsy is a new alternative test in place of a biopsy where they have to go in and they go through your lung and they take a piece of the tumor out. A liquid biopsy is actually where they take your blood, just a normal blood test. These tests can actually find fragments of the tumor DNA floating around in the blood.