Central nervous system (CNS) metastases in lung cancer are a frequent cause of morbidity and mortality. There are conflicting data on the incidence of CNS metastases in stage IV ROS1-positive NSCLC and the rate of CNS progression during crizotinib therapy.

A retrospective review of 579 patients with stage IV NSCLC between June 2008 and December 2017 was performed. Brain metastases and oncogene status (ROS1, ALK receptor tyrosine kinase gene [ALK], EGFR, KRAS, BRAF, and others) were recorded. We measured progression-free survival and time to CNS progression in ROS1-positive and ALK-positive patients who were taking crizotinib.

We identified 33 ROS1-positive and 115 ALK-positive patients with stage IV NSCLC. The incidences of brain metastases for treatment-naive, stage IV ROS1-positive and ALK-positive NSCLC were 36% (12 of 33) and 34% (39 of 115), respectively. There were no statistically significant differences in incidence of brain metastases across ROS1, ALK, EGFR, KRAS, BRAF, or other mutations. Complete survival data were available for 19 ROS1-positive and 83 ALK-positive patients. The median progression-free survival times for ROS1-positive and ALK-positive patients were 11 and 8 months, respectively (p = 0.304). The CNS was the first and sole site of progression in 47% of ROS1-positive (nine of 19) and 33% of ALK-positive (28 of 83) patients, with no statistically significant differences between these groups (p = 0.610).

Brain metastases are common in treatment-naive stage IV ROS1-positive NSCLC, though the incidence does not differ from that in other oncogene cohorts. The CNS is a common first site of progression in ROS1-positive patients who are taking crizotinib. This study reinforces the importance of developing CNS-penetrant tyrosine kinase inhibitors for patients with ROS1-positive NSCLC.