Genomic Analysis and Clinical Correlation of Non-Small Cell Lung Cancer with Special Reference to Brain Metastasis

Next-generation sequencing (NGS) has improved genomic analysis depth in precision oncology. This study analyzed genomic biomarker testing in stage IV NSCLC, focusing on brain metastasis and clinicopathological correlations.

To study molecular markers and clinicopathological correlations in stage IV NSCLC patients, with and without brain metastasis.

A total of 169 stage IV NSCLC patients were studied from April 2023 to May 2025. Demographic data, clinical presentations, and mutation analyses were assessed using NGS on tissue blocks or liquid biopsies.

Among 169 patients, 41.42% (n = 70) had brain metastasis (NSCLC-BM), while 58.58% (n = 99) had no brain metastasis (mNSCLC). Median ages were 51.5 and 56 years, respectively. Adenocarcinoma comprised 95.27% (n = 161) of cases. The cerebral hemisphere was the most common intracranial metastatic site, while skeletal involvement was the most common extracranial site. Headache was the predominant neurological symptom. EGFR mutations were the most common overall. EGFR > TP53 > ALK > other mutations were observed in NSCLC-BM, while EGFR > TP53 > KRAS > other mutations were seen in mNSCLC. Mutation analysis stratified by smoking history (χ²(1) = 1.347, p = 0.245) and sex (χ²(1) = 0.0302, p = 0.862) was not statistically significant. The benefit of gefitinib plus chemotherapy in EGFR exon 19 and exon 21 L858R mutations was greater in mNSCLC (log-rank χ²(1) = 10.813, p = 0.001) than in NSCLC-BM (log-rank χ²(1) = 3.100, p = 0.078). Median survival was 11 months (95% CI: 7.506-14.494) for NSCLC-BM versus 21 months (95% CI: 8.365-33.635) for mNSCLC, with a statistically significant difference (log-rank χ²(1) = 8.639, p = 0.003).

NSCLC-BM showed higher genomic biomarker enrichment (80% vs. 68.68%) but poorer outcomes than mNSCLC. EGFR was the most common targetable mutation, followed by ALK in NSCLC-BM and KRAS in mNSCLC.