Evaluating Progression on First-Line Osimertinib and the Role of Rebiopsy

Julia Rotow, MD, of Dana-Farber Cancer Institute, opens this OncLive Insights discussion on EGFR-mutant non–small cell lung cancer with Ticiana Leal, MD, of Winship Cancer Institute of Emory University, by asking what progression on first-line osimertinib looks like in clinic. Dr Leal says the pattern varies and that she individualizes the next step, starting with restaging to distinguish oligometastatic progression from progression at multiple sites, imaging the central nervous system (CNS) for brain or leptomeningeal disease, and reinterrogating the tumor with a liquid biopsy plus a tissue biopsy when safe and feasible, in part to rule out small cell transformation. She estimates that about 30% of patients cannot undergo repeat biopsy because of CNS-only progression, illness, or declining the procedure. Dr Rotow adds that liquid biopsy offers a rapid first look but can miss histologic transformation and immunohistochemistry-based markers such as MET and HER2.