STK11/LKB1 alterations worsen the poor prognosis of KRAS mutated early-stage non-squamous non-small cell lung carcinoma, results based on the phase 2 IFCT TASTE trial

Background: STK11/LKB1 mutations have been associated with primary resistance to PD-1 axis inhibitors and poor prognosis in advanced KRAS-mutant lung adenocarcinoma. This study aimed to assess the prognostic significance of STK11/LKB1 alterations in localized non-squamous non-small cell lung carcinoma (non-sq NSCLC). Patients and methods: Surgical samples from patients undergoing complete resection for stage IIa, IIb, or IIIa (N2 excluded) non-sq NSCLC in the randomized adjuvant phase II trial (NCT00775385 IFCT-1801 TASTE trial) were examined. Patients received either standard chemotherapy (Pemetrexed Cisplatin) or personalized treatment based on EGFR mutation (Erlotinib) and ERCC1 expression. Tumor molecular profiles were analyzed using targeted NGS and correlated with overall survival (OS) and disease-free survival (DFS), adjusting for relevant clinical variables. Additionally, interactions between treatment groups and molecular alterations on OS, PD-L1 expression, and tumor-circulating DNA in post-operative plasma samples were evaluated. Results: Among 134 patients (predominantly male smokers with adenocarcinoma), KRAS mutations were associated with shorter DFS (HR: 1.95, 95 % CI: 1.1-3.4, p = 0.02) and OS (HR: 2.32, 95 % CI: 1.2-4.6, p = 0.014). Isolated STK11/LKB1 mutations (n = 18) did not significantly impact DFS or OS. However, within KRAS-mutated samples (n = 53), patients with concurrent STK11/LKB1 mutations (n = 10) exhibited significantly shorter DFS (HR: 3.85, CI: 1.5-10.2, p = 0.006) and a trend towards shorter OS (HR: 1.80, CI: 0.6-5.3, p = 0.28). No associations were found between PD-L1 expression, other gene mutations, progression-free survival (PFS), or OS. Conclusion: This analysis reinforces KRAS mutations as predictive factors for relapse and poor survival in localized non-sq NSCLC. Furthermore, the presence of concomitant STK11/LKB1 mutations exacerbated the prognosis within the KRAS-mutated subset. These findings emphasize the clinical relevance of these molecular markers and their potential impact on treatment strategies in non-sq NSCLC.