Clinical Outcome With Platinum-Based Chemotherapy in Patients With Advanced Nonsquamous EGFR Wild-Type Non–Small-Cell Lung Cancer Segregated According to KRAS Mutation Status

BackgroundWe hypothesized that KRAS mutations function as a marker of poor sensitivity to first-line platinum-based chemotherapy in patients with advanced nonsquamous EGFR wild-type (WT) non–small-cell lung cancer (NSCLC).Patients and MethodsConsecutive advanced nonsquamous EGFR WT NSCLCs treated at the Medical Oncology of Perugia with simultaneous assessment of KRAS mutation status were eligible. Anaplastic lymphoma kinase (ALK) gene status was known in roughly half of the patients who had KRAS WT.ResultsTwo hundred four patients were included. Among them, the 77 individuals carrying a KRAS-mutant phenotype experienced a significantly inferior outcome in terms of response rate (P = .04), disease control rate (P = .05), and progression-free survival (PFS) (P = .05) compared with the EGFR WT/KRAS WT population. The association between KRAS mutation and shorter PFS remained statistically significant at multivariate analysis (hazard ratio [HR], 1.45). In addition, patients with KRAS mutations reported a significantly shorter overall survival (OS) compared with patients with EGFR WT/KRAS WT/ALK negativity (n = 64) (P = .02). Among patients with KRAS mutations, those harboring a mutation at codon 13 (n = 12) performed worse than those with a mutation at codon 12 (n = 62) in terms of both PFS and OS (P = .09 for both).ConclusionKRAS mutation appears to negatively affect sensitivity to first-line platinum-based chemotherapy in patients with advanced nonsquamous EGFR WT NSCLC. Studies on larger case series are needed to address differences in clinical outcome according to the type of mutation.