Clinical study on different doses and fractionated radiotherapies for multiple brain metastases of non-EGFR mutant lung adenocarcinoma.

BACKGROUND: To study the effects and adverse reactions of different doses and fractionated radiotherapies on non-epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma patients with multiple brain metastases. METHODS: In total, 80 patients eligible for inclusion were randomly divided into 4 groups. Group A included whole brain radiotherapy (WBRT) alone 300 cGy/fraction ×10 fractions, at a total dose of 3,000 cGy. Group B included WBRT alone 180 cGy/fraction ×22 fractions, at a total dose of 3,960 cGy. Group C included intracranial metastases radiotherapy alone 250 cGy/fraction ×22 fractions at a total dose of 5,500 cGy. Group D included the whole brain + intracranial metastases group (SIB group) whole brain 180 cGy/fraction ×22 fractions intracranial metastases 250 cGy/fraction ×22 fractions, at a total dose 3,960 cGy, 5,500 cGy, respectively. RESULTS: The median survival time of intracranial disease-free survival (IPFS) in group A, group B, group C, and group D was 6, 9, 8, and 13 months, respectively (P=0.000). The median overall survival (OS) time was 16, 24.5, 24, and 30 months, respectively (P=0.150). There was a significant difference in IPFS between different doses and fractionated radiotherapies, but there was no difference in OS. Multivariate analysis showed that the radiotherapy dose of intracranial metastases was positively correlated with IPFS and OS. The incidence rate of adverse reaction of memory decline in 0.5, 1, and 2 years in group A, group B, group C, and group D was respectively 10.0%, 15.0%, 5.0%, and 15.0% (P=0.006); 20.0%, 45.0%, 30.0%, and 60.0% (P=0.000); 10.0%, 20.0%, 35.0%, and 65.0% (P=0.000). The incidence rates of memory decline in the groups of WBRT were significantly more increased than in the non-WBRT group. CONCLUSIONS: Radiotherapy is effective for multiple brain metastases of lung adenocarcinoma, the increase of radiotherapy dose can improve IPFS and OS, and the adverse reaction of memory decline after WBRT is increased but tolerable. Therefore, WBRT and simultaneous integrated boost (SIB) radiotherapy of intracranial metastases is recommended for multiple brain metastases of non-EGFR-mutant lung adenocarcinoma.