Clinicopathological features and clinical efficacy of crizotinib in Chinese patients with ROS1 -positive non-small cell lung cancer.

C-ros oncogene 1 receptor tyrosine kinase ( ROS1 ) rearrangement forms a novel molecular subgroup of non-small cell lung cancer (NSCLC). The present study explored the clinicopathological features and clinical efficacy of crizotinib in patients with ROS1 -positive NSCLC. A retrospective analysis of 2,617 cases of NSCLC diagnosed between January 2013 and December 2016 was performed. ROS1 fusion genes were detected by reverse transcription-quantitative polymerase chain reaction, fluorescence in situ hybridization or next-generation sequencing techniques, and patients positive for the ROS1 fusion gene received oral treatment with crizotinib. The ROS1 fusion was identified in 67 out of 2,617 cases (2.56%), including 21 cases that were male and 46 cases that were female. The median age was 68 years. Among these cases, 59 (88.06%) were adenocarcinoma and 8 were non-adenocarcinoma. According to Tumor-Node-Metastasis (TNM) staging, 4 cases were stage I-IIIa and 63 (94.02%) were stage IIIb-IV. The epidermal growth factor receptor (EGFR) gene status included 60 cases of wild-type, 1 case of co-mutation and 6 unknown cases. Statistically significant differences were identified for sex, TNM staging and EGFR gene status between ROS1 fusion gene-positive and -negative patients (P<0.001). A total of 23 patients received oral treatment with crizotinib, of which 13 (56.52%), 5 (21.74%) and 5 (21.74%) patients demonstrated a partial response, stable disease and progressive disease, respectively. The objective response rate was 56.52% and the disease control rate was 78.26%. Among all patients, the median progression-free survival (mPFS) time was 14.5 months. No differences were revealed in the mPFS time with regard to age, sex, smoking history, performance status score, histopathological type, TNM staging, tumor protein p53 gene status, EGFR gene status and first-line crizotinib treatment, whether by single or multiple factor analysis. The grade 3/4 treatment-associated adverse events included gastrointestinal disturbance, followed by increased transaminase concentration. In conclusion, the rate of ROS1 fusion in NSCLC among the patients is low, and crizotinib is an effective and safe drug for the treatment of ROS1 -positive advanced NSCLC.