Prognostic factors influencing overall survival in stage IV EGFR-mutant NSCLC patients treated with EGFR-TKIs

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the established first-line treatment for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations, but survival advantages in advanced-stage cases remain modest and show interpatient variability. This study seeks to delineate real-world survival outcomes in stage IV EGFR-mutant NSCLC patients undergoing treatment with EGFR-TKIs and to identify independent prognostic factors impacting overall survival (OS). The findings are expected to be a reference for clinicians in managing advanced lung cancer patients. Clinical characteristics from advanced EGFR-mutant NSCLC patients who received EGFR-TKIs were retrospectively analyzed to investigate the association between clinical factors and overall survival. The median OS was 40.60 months (95% confidence interval: 34.72–46.48 months), with expected 1-, 3-, and 5-year OS of 87.2%, 57.8%, and 34.0%, respectively. Patients exhibiting specific characteristics, such as being under 60 years old, having stage IVA disease, adenocarcinoma histology, no liver or brain metastases, negative for neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), cytokeratin fragment 19 (CYFRA 21 − 1), progastrin-releasing peptide (ProGRP), and those who received chemotherapy and radiotherapy exhibited significantly longer survival times compared to patients with the opposite characteristics (being 60 years or older, having stage IVB or IVC disease, non-adenocarcinoma histology, presence of liver or brain metastases, positive for CEA, NSE, ProGRP, CYFRA 21 − 1, and not receiving chemotherapy or radiotherapy) (P < 0.05). Cox univariate and multivariate analyses identified pathological type, liver metastasis, brain metastasis, NSE, CYFRA 21 − 1, EGFR-TKIs type, radiotherapy, and chemotherapy as independent prognostic factors for patients with stage IV NSCLC treated with EGFR-TKIs. Pathological type, liver metastasis, brain metastasis, NSE, and CYFRA 21 − 1 were identified as independent risk factors for stage IV NSCLC patients treated with EGFR-TKIs, while chemotherapy and radiotherapy were determined to be independent protective factors. Taking icotinib or gefitinib, as opposed to osimertinib, was an independent risk factor for advanced NSCLC patients.