Kirsten Rat Sarcoma Virus Mutations Effect On Tumor Doubling Time And Prognosis Of Solid Dominant Stage I Lung Adenocarcinoma

Introduction: To analyze the impact of Kirsten-Rat-Sarcoma Virus (KRAS) mutations on tumor-growth as estimated by tumor-doubling-time (TDT) among solid-dominant clinical-stage I lung adenocarcinoma. Moreover, to evaluate the prognostic role of KRAS mutations, TDT and their combination in completely-resected pathologic-stage I adenocarcinomas. Methods: In this single-center retrospective analysis, completely resected clinical-stage I adenocarcinomas presenting as solid-dominant nodules (consolidation-to-tumor ratio > 0.5) in at least 2 preoperative computed-tomography scans were enrolled. Nodules’ growth was scored as fast (TDT < 400 days) or slow (TDT > 400 days). KRAS-mutated adenocarcinomas were identified with next-generation sequencing. Logistic- and Cox-regressions were used to identify predictors of fast-growth and disease-free survival (DFS), respectively. Results: Among 151 patients, 83 (55%) had fast-growing nodules and 64 (42.4%) were KRAS-mutated. Fast-growing nodules outnumbered in the KRAS-mutated group (n = 45; 70.3%), median TDT 95-days (interquartile range, IQR 43.5-151.5) compared to the KRAS wild-type group (38, 43.7%), median TDT 138-days (IQR 70.3-278.5). KRAS-mutations predicted faster-growth at multivariable analysis (P = .009). In a subgroup analysis including 108 pathologic-stage I adenocarcinomas, neither KRAS-mutations (P = .081) nor fast-growing pattern (P = .146) affected DFS. Nevertheless, the association of KRAS-mutations and fast-growing pattern identified a subgroup of patients with worse DFS (P = .02). The combination of fast-growing and KRAS-mutations (hazard-ratio 2.97 [95%CI 1.22-7.25]; P = .017) and average nodule diameter at diagnosis (hazard-ratio 1.08 [95%CI 1.03-1.14]; P = .004) were independent predictors of worse DFS. Conclusion: KRAS mutations are associated to faster growth, in clinical-stage I adenocarcinoma presenting at diagnosis as solid-dominant nodules undergoing complete resection. Moreover, faster-growth identifies a subgroup of pathologic-stage I KRAS-mutated adenocarcinomas with higher recurrences.