Value of early radiotherapy for EGFR mutation-positive non-small cell lung cancer with brain metastasis in the era of third-generation targeted drugs: a single center retrospective study of 85 cases / 中华放射肿瘤学杂志

ABSTRACT

Objective:To explore the reasonable timing of radiotherapy for epidermal growth factor receptor ( EGFR) mutation-positive non-small cell lung cancer patients with brain metastasis in the era of third-generation targeted drugs. Methods:Clinical data of EGFR mutation-positive non-small cell lung cancer patients with brain metastasis who received first-line treatment with third-generation targeted drugs and stereotactic radiotherapy at Shanghai Armed Police Corps Hospital from September 2019 to May 2022 were retrospectively analyzed. According to the timing of radiotherapy before / after targeted drug resistance, all patients were divided into the early and salvage radiotherapy groups. The proportion of brain metastasis, physical fitness, complete response rate, objective response rate, delaying the progression of brain metastasis and overall survival (OS) were compared between two groups. Kaplan-Meier method was used for survival analysis, log-rank test was used for univariate prognostic analysis, and factors with P <0.1 were included in Cox multivariate analysis. Results:A total of 85 patients were included, including 51 (60%) cases receiving early radiotherapy. Patients who participated in early radiotherapy had a higher proportion of symptomatic brain metastasis (82% vs. 56%, P=0.013) and poorer physical fitness (Kanofsky performance score <70 61% vs. 26%, P=0.002) compared to patients who underwent salvage radiotherapy. Early radiotherapy significantly improved the complete response rate of intracranial lesions (35% vs. 12%, P=0.015) and objective response rate (88% vs. 71%, P=0.041), delayed the progression of brain metastasis (median intracranial progression free survival 23.0 months vs. 16.0 months, P=0.005; median intracranial secondary progression free survival 31.0 months vs. 22.0 months, P=0.021), and improved OS (median OS 44.0 months vs. 35.0 months, P=0.046). In multivariate analysis, diagnosis-specific graded prognostic assessment score <2.5, mutation of EGFR exon 21, and salvage brain radiotherapy were adverse prognostic factors for OS. Conclusion:In the era of third-generation targeted drugs therapy, early involvement of stereotactic radiotherapy in non-small cell lung cancer patients with brain metastasis can bring greater clinical benefits.