Thoracic Radiotherapy and Radiation Time Would Affect the Efficacy of Advanced Non-Small Cell Lung Cancer for Patients Who Responded to TKIs Treatment.

[PURPOSE] This trial aimed to investigate the difference in treatment efficacy of thoracic radiotherapy before and after thoracic progression during treatment with EGFR-TKI to determine the optimal timing of consolidation thoracic radiotherapy.

[MATERIALS AND METHODS] 815 patients with histologically confirmed advanced NSCLC with EGFR mutation received 1-3 generation EGFR-TKIs or EGFR-TKIs treatment plus thoracic radiotherapy from May 2017 to May 2020.. For patients who received thoracic radiotherapy, 196 received thoracic radiotherapy before thoracic progression, and 244 patients received thoracic radiotherapy after thoracic progression. Kaplan-Meier analysis and log-rank test were used to compare survival differences for radiotherapy sequences.

[RESULTS] There was a significant statistical difference in the median OS[mOS: 31.8 vs 18.4 months, HR=0.60(0.479, 0.952), P=0.000] and PFS[mPFS: 22.6 vs 14.0 months, HR=0.60(0.485, 0.736), P=0.000] between TKIs plus radiotherapy group and TKIs group. For patients who received thoracic radiotherapy, 5-year OS rates were 43.6% and 28.2% in the pre-progression and post-progression groups, respectively (HR=0.67, P=0.047). The median OS was 33.7 months (22.10-38.1) and 27.8 months (19.16-27.90) for the two groups, respectively. 5-year progression-free survival rates were 71.8% and 54.5% in the pre-progression group and post-progression group, respectively (HR=0.73,P=0.043). The median PFS was 27.4 months (23.48-31.25) and 19.2 months (15.94-22.53) for the two groups, respectively.

[CONCLUSION] It indicated that advanced stage NSCLC with positive EGFR mutation had better long-term survival if patients underwent thoracic radiotherapy before thoracic progression in the TKIs treatment.