Upfront thoracic radiotherapy to primary lesion improves outcomes in patients with stage IV non-small cell lung cancer harboring EGFR mutations.

PURPOSE: The role of thoracic radiotherapy in the treatment of metastatic EGFR mutant non-small cell lung cancer (NSCLC) patients in literature data are insufficient.The purpose of this study was to examine the effectiveness of upfront thoracic radiotherapy in metastatic EGFR mutant NSCLC patients treated with chemotherapy or tyrosine kinase inhibitors (TKI). METHODS: This study was designed as a hospital-based retrospective observational case-series study. A total of 141 patients with metastatic EGFR mutant NSCLC who were followed in two different oncology centers in Turkey between 2014 and 2019 have been included into this study. RESULTS: The median patient age was 63 years (range 35-91). EGFR mutation results of exon 19 deletion, exon 21 mutation and exon 18 mutation were found in 82 (58.2%), 56 (39.7%) and 3 (2.1%) patients, respectively.The median follow-up time was 22 months and 94 (33.3%) patients died during follow-up. Median overall survival (OS) was 26 months and progression free survival (PFS) (for first line treatment) was 10 months for the whole cohort, respectively. Radiotherapy was given to the primary tumor site in 32 (22.6%) patients. Patients receiving radiotherapy to primary tumor site had better OS than those who had not (31 versus 23 months respectively, p=0.02). Survival advantage was also seen for patients group taking TKI at upfront setting (33 versus 23 months respectively, p=0.05). CONCLUSION: In this study, we have shown that upfront thoracic radiotherapy to primary lesion as combination with EGFR-TKI treatment may improve the outcome in advanced stage IV NSCLC patients harboring EGFR mutations.