Clinical Impact of Continued Crizotinib Administration after Isolated Central Nervous System Progression in Patients with Lung Cancer Positive for ALK Rearrangement

Introduction: Although crizotinib manifests marked antitumor activity in individuals with non-small-cell lung cancer positive for ALK abnormalities, all treated patients ultimately develop resistance to this drug. The central nervous system (CNS) is a frequent site of disease progression in such patients, with palliative radiotherapy usually being administered for the CNS metastasis. However, subsequent chemotherapy has not been optimized in these patients. Methods: We retrospectively evaluated the continuation of crizotinib treatment after radiotherapy for isolated CNS progression in ALK-rearrangement-positive non-small-cell lung cancer patients. Results: Among 21 ALK-rearrangement-positive patients treated with crizotinib, seven individuals resumed daily crizotinib administration after the completion of radiotherapy for isolated CNS failure. All these patients continued to receive crizotinib for at least 4 months after radiotherapy without disease progression. One patient experienced a recurrent isolated CNS failure during the second period of crizotinib administration but subsequently resumed crizotinib treatment again for at least 8.5 months after another application of radiotherapy. Conclusions: Development of isolated CNS metastasis is emerging as a clinical concern for patients treated with crizotinib. Our data suggest that continued administration of crizotinib after radiotherapy for isolated CNS progression is a potential treatment option for such patients.