Fifty-five months progression-free survival with crizotinib treatment in coexistence of ALK and ROS1 rearrangements in lung adenocarcinoma: an extremely rare case and review of the literature.

We wanted to present a case with coexistence of anaplastic lymphoma kinase (ALK) and c-ros oncogene 1 (ROS1) rearrangements that has been in remission for a long time with crizotinib. A 62-year-old nonsmoker male patient was diagnosed with Non-small cell lung cancer. Progression developed 9 months after the treatment, and coexistence of ALK and ROS1 positivity were detected in driver mutation analysis performed with fluorescent in situ hybridization. Crizotinib 2 × 250 mg was started in November 2016. The treatment of the patient, who has been in remission for approximately 55 months since then, continues. Until recently, the use of next-generation sequencing (NGS) was not common, but the more frequent epidermal growth factor receptor, then ALK, and finally ROS1 mutation were studied in tumor tissues. Sometimes ROS1 was not studied because there was not enough tissue left. We think that this rate will increase a little more with the widespread use of NGS from now on. Showing that ALK and ROS1 are positive together, longer survivals can be obtained by choosing therapies that are responsive to both.