Figure 4.

Case example of high burden of baseline brain metastasis with durable response to osimertinib. Top row illustrates representative index lesions from the baseline (pre-osimertinib) scan. Middle row illustrates the first MRI after initiation of osimertinib which already had significant regression of disease. The patient remained controlled intracranially until 34 months post-osimertinib, at which point he developed a subcentimeter new lesion which was subsequently treated with SRS. MRI, magnetic resonance imaging; SRS, stereotactic radiosurgery.