The prognostic impact of KRAS, its codon and amino acid specific mutations, on survival in resected stage I lung adenocarcinoma.

BACKGROUND: Despite complete surgical resection, patients with stage I non-small-cell lung cancer (NSCLC) are at risk for disease recurrence. The impact of common oncogenic driver mutations on prognosis in stage I NSCLC is limited. The pure prognostic value of KRAS mutational status was explored in resected stage I lung adenocarcinoma.

METHODS: Mutation status was tested in patients who had complete resection of stage I lung adenocarcinoma without any adjuvant therapy, using a multiplex polymerase chain reaction)-based assay. Disease-free survival (DFS) and overall survival (OS) were compared between patients with KRAS-mutant (KRAS-MUT), KRAS-MUT subtypes, and KRAS wild-type (KRAS-WT) tumors.

RESULTS: A total of 312 patients were included in this analysis; 127 harbored KRAS mutations and 185 had KRAS-WT tumors. When compared with KRAS-WT, KRAS-MUT was associated with significantly shorter OS (hazard ratio 4.36, 95% confidence interval 2.09-9.07; p < 0.0001) and DFS (hazard ratio 3.62, 95% confidence interval 2.11-6.22; p < 0.0001). When stratifying KRAS-WT patients based on EGFR status, KRAS-MUT patients had worse OS (p = 0.0001) and DFS (p < 0.0001) than patients with EGFR-MUT and EGFR-WT/KRAS-WT (WT/WT). Patients with codon 12 mutations had superior DFS (p = 0.0314), but there were no differences in OS compared with mutations found in codons 13 and 61 (p = 0.1772). We observed better DFS associated with G12C/G12V mutations compared with other amino acid specific KRAS mutations (p = 0.0271) with a trend towards improved OS (p = 0.0636). Multivariate analysis identified KRAS mutation as independent predictor of worse OS (p = 0.001) and DFS (p < 0.0001).

CONCLUSION: KRAS is an independent prognostic marker in resected stage I lung adenocarcinoma. Differential outcomes are associated with codon and amino acid specific KRAS mutations.