Brain metastases are currently both common in clinical oncology and a critical problem, since they negatively affect patients' quality of life as well as survival. In the era of targeted therapy, survival for metastatic, recurrent lung cancer has improved. However, improved systemic treatment modalities have led to prolonged disease courses and subsequently to an increased incidence of brain metastases.
We recruited patients who were diagnosed with non-small cell lung cancer at a Samsung Medical Center from 2008 to 2017. We collected clinical characteristics and treatment pattern by medical chart review and analyzed their mutation status by NGS (ampliseq and cancer scan).
Among 12918 patients who were diagnosed with non-small cell lung cancer and received chemotherapy, 1566 patients received gamma knife surgery and 1209 patients received whole brain radiotherapy. 3922 were EGFR mutant non-small cell lung cancers and received EGFR tyrosine kinase inhibitors (erlotinib: 1424; gefitinib: 2210; afatinib: 606; dacomitinib: 24). Among EGFR-mutant patients, 663 (16.9%) patients received whole brain radiation therap (WBRT) and 765 (19.5%) received gamma-knife surgery. 320 patients who were diagnosed with ALK-positive non-small cell lung cancer received ALK inhibitors (crizotinib: 308; alectinib 54). Among them 51 (15.9%) received WBRT and 81 (25.3%) patients received gamma-knife surgery. 268 patients received gamma-knife surgery three times or more. 51 patients received gamma-knife surgery five times or more (maximum 14 of gamma-knife surgery). Among them, 27 (52.9%) patients were EGFR mutant and 11 (21.6%) patients were ALK-rearrangement non-small cell lung cancer.
In patients with EGFR-mutant or ALK-rearrangement non-small cell lung cancer, local treatment for brain metastasis was performed frequently. A minority of patients have well controlled extracranial disease but poorly controlled intracranial disease, and in these cases strategies to maintain systemic chemotherapy and persistent topical treatments for brain lesions are also helpful. Further research is needed to find out the unique tumor biology of patients with uncontrolled brain metastases.
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All authors have declared no conflicts of interest.