Materials and Methods: One hundred four NSCLC patients with ALK or ROS1 gene rearrangement were enrolled for first-line therapy with ALK inhibitors (crizotinib in 25 patients, brigatinib in 22 patients, and alectinib in 41 patients) or the ROS1 inhibitor (crizotinib in 16 patients) as part of daily clinical practice in two Polish cancer centers. The gene discussed is ALK; the disease is non-small cell lung carcinoma.