Dr. Tejas Patil discusses the necessity of re-testing lung cancer patients over the course of their treatment, including when additional molecular testing may be appropriate.
Dr. Tejas Patil is an academic thoracic oncologist at the University of Colorado Cancer Center focused on targeted therapies and novel biomarkers in lung cancer. Learn more about Dr. Patil, here.
Is it necessary to retest at any time?
In general, I strongly advocate that patients who are on targeted therapies obtain additional molecular testing after they’ve progressed, and the reason is the following.
Cancer cells evolve resistance mechanisms to overcome targeted therapies and understanding these resistance mechanisms can be quite helpful in designing next lines of treatments.
A very good example of this is in EGFR lung cancer. The very first type of targeted therapy for EGFR positive lung cancer was a drug called Erlotinib. What we had seen was that when patients were on this drug, Erlotinib, they would respond, and they would do really well for a period of time.
But after a period of time, patients would progress on this therapy, and a very common mutation that we would find, once they progressed was a mutation called T790M. By biopsying this patient and finding this mutation, it was very helpful because it allowed the medical community and researchers to investigate a new drug called Osimertinib, which can overcome that resistance mutation.
And we’re learning a lot about resistance pathways and resistance mutations in lung cancer, so I think it’s very important that patients who are on targeted therapies specifically get retested and re-biopsied.