Crizotinib was approved for ROS1 fusion gene-positive non-small cell lung cancer, and a ROS1 fusion gene detection kit based on the reverse transcription-polymerase chain reaction (RT-PCR) method was approved to detect the ROS1 fusion gene. It is recommended that a fresh specimen be used because the RNA present in the analysis sample often degrades when stored over a longer period.
A 70-year-old man who underwent right upper lobectomy for lung adenocarcinoma 14 years previously was referred to us for detailed examination of a mass on the right side of the back. Biopsies of the tumor confirmed a diagnosis of metastatic ROS1 fusion gene-positive non-small cell lung cancer, and a lung cancer surgical specimen collected 14 years earlier was revealed to be ROS1 fusion gene-positive. We report a case in which an existing lesion confirmed late recurrence of lung adenocarcinoma for which he had received surgery many years earlier.