KRAS mutation is a weak, but valid predictor for poor prognosis and treatment outcomes in NSCLC: A meta-analysis of 41 studies

// Wei Pan 1, 2 , Yan Yang 1 , Hongcheng Zhu 1 , Youcheng Zhang 3 , Rongping Zhou 3 , Xinchen Sun 1 1 Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China 2 Department of Oncology, The Second Hospital of Nanjing Jiangning, Nanjing, Jiangsu, P.R. China 3 Department of Oncology, Nanjing Jiangning Hospital, Nanjing, Jiangsu, P.R. China Correspondence to: Xinchen Sun, e-mail: starrystyle@hotmail.com Keywords: non-small cell lung cancer, KRAS mutation, prognosis, EGFR-TKI, meta-analysis Received: July 30, 2015      Accepted: January 13, 2016      Published: January 30, 2016 ABSTRACT Mutation of oncogene KRAS is common in non-small cell lung cancer (NSCLC), however, its clinical significance is still controversial. Independent studies evaluating its prognostic and predictive value usually drew inconsistent conclusions. Hence, We performed a meta-analysis with 41 relative publications, retrieved from multi-databases, to reconcile these controversial results and to give an overall impression of KRAS mutation in NSCLC. According to our findings, KRAS mutation was significantly associated with worse overall survival (OS) and disease-free survival (DFS) in early stage resected NSCLC (hazard ratio or HR=1.56 and 1.57, 95% CI 1.39-1.76 and 1.17-2.09 respectively), and with inferior outcomes of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) treatment and chemotherapy (relative risk or RR=0.21 and 0.66 for objective response rate or ORR, 95% CI 0.12-0.39 and 0.54-0.81 respectively; HR=1.46 and 1.30 for progression-free survival or PFS, 95%CI 1.23-1.74 and 1.14-1.50 respectively) in advanced NSCLC. When EGFR mutant patients were excluded, KRAS mutation was still significantly associated with worse OS and PFS of EGFR-TKIs (HR=1.40 and 1.35, 95 % CI 1.21-1.61 and 1.11-1.64). Although KRAS mutant patients presented worse DFS and PFS of chemotherapy (HR=1.33 and 1.11, 95% CI 0.97-1.84 and 0.95-1.30), and lower response rate to EGFR-TKIs or chemotherapy (RR=0.55 and 0.88, 95 % CI 0.27-1.11 and 0.76-1.02), statistical differences were not met. In conclusion, KRAS mutation is a weak, but valid predictor for poor prognosis and treatment outcomes in NSCLC. There’s a need for developing target therapies for KRAS mutant lung cancer and other tumors.