1342P - Effect of the timing of intervention in craniocerebral radiotherapy on prognosis of patients with EGFR-mutant lung adenocarcinoma with brain metastasis

Background

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 craniocerebral radiotherapy in patients with EGFR mutant lung adenocarcinoma BM before and after EGFR-TKI resistance.

Methods

A total of 217 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. The patients were divided into two groups according to the timing of craniocerebral radiotherapy intervention.: before EGFR-TKI resistance and after EGFR-TKI resistance. 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. Brain radiotherapy included WBRT, local radiotherapy, and WBRT+Boost.

Results

The median age at diagnosis was 54 years (range: 32–81 years). Most patients were female (65.9%) and non-smokers (77.4%). Eighty-nine pairs of patients were matched using PSM. The median iPFS for before EGFR-TKI resistance (n=46) and after EGFR-TKI resistance (n=46) was 17.9 and 9.5 months, respectively(P=0.0376). The median OS for before EGFR-TKI resistance (n=89) and after EGFR-TKI resistance (n=89) was 36.9 and 42.1 months, respectively(P=0.6626).

Conclusions

In EGFR-mutant lung adenocarcinoma patients with BM, craniocerebral radiotherapy before EGFR resistance is beneficial to the prolongation of iPFS in patients, but this prolongation does not translate into the benefit of OS.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.