Objective: Stereotactic radiosurgery (SRS), combined with contemporary targeted therapies and immunotherapies, has improved the overall survival of patients with lung adenocarcinoma (ADC). Given that histological subtypes reflect prognosis in patients with primary ADC, it is important to integrate pathological biomarkers to predict clinical outcomes after SRS in patients with brain metastases from lung ADC. Therefore, the authors investigated the prognostic relevance of various biomarkers of primary lung ADC for clinical outcomes after SRS.
Methods: A total of 95 patients with 136 brain metastases (1-4 oligometastases) who were treated with Gamma Knife radiosurgery between January 2017 and December 2020 were included. The Kaplan-Meier method and univariate and multivariate analyses using Cox proportional hazard regression models were used to identify prognostic factors for local control, survival, and distant brain control.
Results: Multivariate analysis revealed thyroid transcription factor 1 as an independent prognostic factor for local control (HR 0.098, 95% CI 0.014-0.698, p = 0.0203) and napsin A as a significant predictor of overall survival after SRS (HR 0.080, 95% CI 0.017-0.386, p < 0.01). In a subset analysis of epidermal growth factor receptor (EGFR) mutation, patients with EGFR exon 19 mutations showed better distant brain control than those with EGFR exon 21 mutations (p < 0.01).
Conclusions: Pathological biomarkers of primary cancer should be considered to predict clinical outcomes after SRS in patients with lung ADC. Use of such biomarkers may help to provide personalized treatment to each patient, improving clinical outcomes after SRS.
Keywords: EGFR; TTF-1; brain metastases; lung adenocarcinoma; napsin A; oncology; stereotactic radiosurgery.