Thirty patients were evaluable for progression-free survival (PFS), and 29 patients were evaluable for best response....Crizotinib was highly active at treating lung cancer in patients with a ROS1 rearrangement, suggesting that patients with lung adenocarcinomas should be tested for ROS1....Crizotinib seems to be the current treatment of choice for ROS1-positive patients.

We present the case of ROS1- rearranged lung cancer successfully resected after response to crizotinib….ROS1 rearrangement was detected by reverse transcriptase polymerase chain reaction. The patient was diagnosed with ROS1-rearranged lung adenocarcinoma (cT4N2M0, stage IIIB) and was treated with crizotinib (250 mg twice daily) as first-line chemotherapy. After 8 weeks of treatment, chest CT showed a significant decrease in the size of the tumor and lymph nodes (Fig. 1e, d), especially mediastinal lymph nodes were markedly reduced.

CONTRADICTING EVIDENCE: Molecular testing of the lung tumor revealed a ROS1 rearrangement by fluorescence in situ hybridization (FISH)….received crizotinib 250 mg twice a day with tumor reduction (best response of 30.1% reduction according to RECIST version 1.1). After 43 months, imaging revealed isolated progression of a left lower lobe lung nodule, with continued response elsewhere. Repeat biopsy of this lung nodule (T2, Fig. 1a) confirmed adenocarcinoma.