ESTRO 2024 - Abstract Book

S1733

Clinical - Lung

ESTRO 2024

Shandong Cancer Hospital and Institute,Shandong First Medical University and Shandong Academy of Medical Sciences, Department of Radiation Oncology, jinan, China

Purpose/Objective:

The probability of brain metastasis (BMs) in lung cancer patients with epidermal growth factor receptor (EGFR) mutation is always high. Craniocerebral radiotherapy is the cornerstone for the treatment of BM, which plays an indispensable role together with EGFR-TKI. However, the timing of intervention in craniocerebral radiotherapy has always been a controversial issue. The purpose of this study was to evaluate the efficacy of intervention timing of craniocerebral radiotherapy combined with third-generation EGFR-TKIs on prognosis of patients with EGFR mutant lung adenocarcinoma complicated with brain metastasis.

Material/Methods:

A total of 348 patients with advanced non-small cell lung cancer (NSCLC) and EGFR mutations were enrolled in this retrospective cohort study. Propensity score matching (PSM) was conducted using a nearest-neighbor algorithm (1:1) to adjust for demographic and clinical covariates. According to whether combined with craniocerebral radiotherapy, the patients were divided into two groups: EGFR-TKIs+craniocerebral radiotherapy group and EGFR TKI alone group. The patients were divided into two groups according to the timing of craniocerebral radiotherapy intervention.: b upfront-group and delay-group. Intracranial progression-free survival (iPFS) and overall survival (OS) were calculated. Kaplan – Meier analysis was used to compare iPFS and OS between the two groups.

Results:

Before PSM, The median OS was 61.4months, while the median iPFS was 15.0months. The median OS of patients in EGFR-TKI+craniocerebral radiotherapy group and EGFR-TKI alone group was 68.2 months and 53.9 months respectively, and there was significant difference (p=0.0444). After PSM, a total of 262 patients were successfully matched, with131 patients in each group. The median OS of EGFR-TKIs+craniocerebral radiotherapy group and EGFR-TKI alone group was 68.1 months and 48.4 months respectively, and there was significant difference between the two groups (p= 0.0178). A total of 206 patients enrolled this part of the study who received craniocerebral radiotherapy. For OS analysis of patients in upfront-group and delay-group showed that the median OS was 78.7 and 67.7 months respectively. There was no significant difference in median OS between upfront-group and delay-group (p =0.2439). In addition, patients were divided into group A (Lung-molGPA1-2) and group B (Lung-molGPA2.5-4) according to Lung-molGPA score. For group A, the median OS of upfront-group and delay-group was 27.9 and 45.3 months, respectively. In the low score group of Lung-molGPA, there was significant difference between upfront-group and delay-group (p = 0.0072). For patients in group B, there was significant difference in OS between the two groups (p = 0.0379). The median OS of the two groups was 110.0 and 70.5 months, respectively.

Conclusion:

EGFR-TKI combined with craniocerebral radiotherapy is more beneficial to the survival of patients with EGFR mutant lung adenocarcinoma with craniocerebral metastasis than EGFR-TKI alone. The importance of craniocerebral