P3.02b-074 Brain Radiotherapy with EGFR-TKI Plays an Important Role in 181 EGFR Mutant Non-Small Cell Lung Cancer Patients with Brain Metastasis: Topic: EGFR Clinical

Abstract

To perform a retrospective analysis of patients with epidermal growth factor receptor (EGFR)-mutant NSCLC patients who developed brain metastases (BM) to assess the appropriate use of EGFR tyrosine kinase inhibitors (TKIs), and radiation therapy (RT) for symptomatic and asymptomatic BM. There were 482 patients diagnosed with EGFR mutant NSCLC between June 2006 and December 2015 at Zhejiang Cancer Hospital. Treatment outcomes had been retrospectively evaluated in 181 patients with 132 asymptomatic BM and 49 symptomatic BM. 39 patients received first-line brain RT, 23 patients received delayed brain RT, and 34 patients did not receive brain RT. In all 49 symptomatic BM patients received radiotherapy, except 4 patients were refusal of treatment. There were 45 patients had brain radiotherapy, 39 received WBRT and 6 were SRS. Among 132 asymptomatic brain metastasis patients, 74 received radiotherapy (63 WBRT and 11 SRS). The BM of 26 patients had still stable by the follow-up time. 22 patients did not get information about brain RT after intracranial progression and until the last follow-up. 10 patients were refusal of brain RT treatment. In 49 symptomatic BM patients, 45 received RT including 40 WBRT and 5 SRS. Among 6 SRS. The iPFS for patients treated with SRS and WBRT was 12.4 months and 9.5 months (P=0.895). Median OS in the SRS group was also greater than in those treated with WBRT (37.7 vs 21.1 months)(P=0.194). In the group of 132 asymptomatic BM patients, There were 86 patients who had not received brain radiotherapy before TKI and 46 received RT whether upfront or concurrent TKI. The median OS in the upfront RT group was also longer than in the upfront TKI (24.9 vs 17.4 months)(P=0.035). Further analysis with subgroup to the timing of using radiotherapy, among the 74 patients, 33 underwent concurrent TKI and radiation therapy, 13 were given TKI after failure of first-line radiotherapy plus chemotherapy and 28 patients received radiotherapy after TKI. The iPFS of three groups was 11.1 months, 11.3 months and 8.1 months (P=0.032). The mOS of three groups was 21.9 months, 26.2 months and 17.1 months (P=0.085). The study suggests that the deferral of brain RT may result in inferior OS in NSCLC patients harboring EGFR mutations and asymptomatic BM. For now, the standard-of-care treatment for newly diagnosed BM whether symptomatic or asymptomatic brain metastases should remain upfront RT followed by EGFR-TKI therapy. First-line brain RT may improve long-term survival in EGFR mutation patients.