Figure 5b:

Images show central nervous system (CNS) progression on crizotinib and subsequent response to alectinib in a patient with anaplastic lymphoma kinase (ALK)-rearranged advanced non–small cell lung cancer. (a) Baseline chest CT image shows dominant consolidative opacity in the right upper lobe and left lung nodules. Note right hydropneumothorax (_*) due to prior thoracentesis. (b, c) The tumor responded very well to crizotinib therapy, with a small residual band-like opacity in the lung (b) after 2 years of crizotinib therapy. However, a new enhancing lesion in the right cerebellum (arrow) was noted at brain MRI, suggesting CNS progression. The patient switched therapy from crizotinib to alectinib, and the cerebellar lesion is seen to have resolved on (d) image from initial follow-up brain MRI 1.5 months after the initiation of alectinib, demonstrating higher effectiveness of alectinib for CNS lesions because of better blood-brain barrier penetration.