Abstract
Introduction : Brain metastasis (BM) commonly occur in non-small cell lung cancer (NSCLC). Data on predictive value of radio-sensitivity of epidermal growth factor receptor (EGFR) mutation in BM are inconclusive. The aim of our study was to evaluate the radio-sensitivity of brain metastasis depending on the genomic status (EGFR, KRAS) of the primary NSCLC tumor. Material and Methods : Between January 2007 and December 2012, we retrospectively reviewed the data from 1971 patients who underwent a molecular testing for NSCLC and focused on 157 patients who underwent a radiation therapy (RT) for BM. Primary endpoint was radio-sensitivity assessed by RECIST criteria. Results : The median age was 58 years-old (28-90). Median follow-up time was 6.5 months (1-60). EGFR was mutated (mEGFR) in 16 patients (10.2%) whereas KRAS was mutated (mKRAS) in 45 patients (28.7%). Radio-sensitivity was significantly higher for mEGFR cases compared to wild type (WT) (OR: 4.96 (95% CI : 1.07 - 23.09, p=0.05)) or mKRAS patients (OR : 1.81 (95% CI : 1.21 – 3.95, p=0.03). Association of RT and treatment by EGFR-tyrosine kinase inhibitors (EGFR-TKI) showed a benefit on radio-sensitivity in mEGFR patients (OR : 5.32 (95% CI : 1.16 – 24.29, p=0.04), and on overall survival (OS) for mEGFR (22 months versus 8 months, p=0.06) as well as for EGFR/KRAS WT patients (17 months versus 8 months, p=0.04). Conclusion: mEGFR seems to be associated with higher radio-sensitivity than WT or mKRAS patients. The association of RT and EGFR-TKI seems to be beneficial on OS in mEGFR and EGFR/KRAS WT patients.
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