Bridging East and West: Real-World Clinicogenomic Landscape of Metastatic NSCLC in Türkiye

Background/Objectives: Genomic profiling guides treatment in metastatic non-small-cell lung cancer (mNSCLC), yet country-level data from Türkiye remain limited. Methods: We retrospectively analyzed consecutive patients with mNSCLC diagnosed between January 2018 and March 2025 across tertiary centers in all seven regions. Variables included demographics, smoking, histology, testing modality (single-gene vs. next-generation sequencing [NGS]), targetable genomic alterations (TGAs) and co-mutations, and programmed death-ligand 1 (PD-L1) tumor proportion score. Results: Among 1023 patients (mean age 64 years; 76.4% male), tobacco exposure was frequent (mean 42.1 pack-years); 16.9% were never-smokers. NGS use increased over time, exceeding 90% by 2025. TGAs were detected in 28.3% (EGFR 16.0%, ALK 5.0%, KRAS G12C 2.6%, BRAF V600E 3.2%; ROS1, MET exon 14, HER2, NTRK ≤ 2.5%; no RET). EGFR alterations occurred in 19% of non-squamous carcinomas and 6% of squamous cell carcinomas (SCCs), suggesting an intermediate East–West pattern. Among NGS-tested samples, TP53 was the most frequent co-mutation (33.1%), followed by alterations in CDKN2A, PIK3CA, FGFR, STK11, and KEAP1. Conclusions: In this large, multicenter Turkish real-world cohort, the TGA spectrum broadly mirrors global patterns while revealing local nuances; EGFR mutations were more frequent than expected in SCC, and nationwide NGS adoption is accelerating. Limitations include retrospective design, non-centralized PD-L1 testing, and missing data. Prospective, standardized studies integrating outcomes and resistance mechanisms are warranted to refine regional precision oncology.