Relationship between metastasis patterns and 1-year survival in advanced-stage EGFR-mutated non-small cell lung cancer patients at Dr. Sardjito General Hospital, Yogyakarta, Indonesia

Abstract

Non-small cell lung cancer (NSCLC) with an EGFR-positive mutation is a key subtype that responds to tyrosine kinase inhibitors (TKI). Although targeted therapy has transformed the treatment landscape, the role of metastasis patterns as a prognostic factor in the TKI era still needs comprehensive evaluation. This study aims to analyze the relationship between metastasis patterns and mortality in advanced-stage, EGFR-mutated NSCLC patients who receive TKI therapy. This was a retrospective cohort study of 60 advanced-stage, EGFR-mutated NSCLC patients who received TKI therapy at Dr. Sardjito General Hospital. The collected data included demographic characteristics, metastasis locations (liver, contralateral lung, bone, brain, and pleura), the number of metastatic organs, and survival time. Survival analysis was performed using the Kaplan-Meier and Cox regression methods. Statistical significance was set at p<0.05. Of the 60 patients, 65% were female with a median age of 60 years. The prevalence of metastasis was: pleura 76.7% (46/60), bone 52.5% (31/59), contralateral lung 49.2% (29/59), liver 30.5% (18/59), and brain 18.6% (11/59). The distribution of patients was 60% oligometastatic (1-2 organs) versus 40% polymetastatic (≥3 organs). The median overall survival was 8.8 months. Univariate analysis showed that only contralateral lung metastasis was a significant protective factor (log-rank p=0.041, HR=0.43, 95%CI: 0.19-0.97), with a median survival of 11.8 months compared to 7.2 months in patients without contralateral lung metastasis. Metastases in other locations—liver (p=0.634, median survival 7.5 vs 9.2 months), bone (p=0.835, median survival 8.7 vs 9.1 months), brain (p=0.861, median survival 8.9 vs 8.8 months), pleura (p=0.684, median survival 8.6 vs 9.5 months)—and the number of metastatic organs (p=0.493) did not show a significant effect on survival. Multivariate analysis confirmed that contralateral lung metastasis was the only significant metastasis location factor (p=0.036, HR=0.38, 95%CI: 0.16-0.94). Contralateral lung metastasis in this study was the only metastasis pattern associated with better survival. This may be linked to the better effectiveness of TKI therapy on metastatic lesions in the contralateral lung compared to other sites. Metastases in other locations and the number of metastatic lesions did not affect survival.