Whole-Brain Radiotherapy Plus Sequential Or Simultaneous Integrated Boost For The Treatment Of Limited Number Of Brain Metastases In Non-Small Cell Lung Cancer

Objectives: There has been no definitive regimens on how to integrate whole brain radiotherapy(WBRT)and local boost for brain metastases(BMs).To compare the therapeutic effect and neurocognitive impairment in non-small cell lung cancer(NSCLC)patients with limited number of BMs(≤10)treated by WBRT plus sequential integrated boost(SEB)or simultaneous integrated boost(SIB).Methods: A total of 52 non-small cell lung cancer patients with limited number of BMs(≤10)who underwent IMRT from January 2013 to December 2016 were retrospectively analyzed.20 cases in group A were irradiated by WBRT+ SEB(first 3Gy*10Fx for WBRT then 4Gy*3Fx for BMs)and 32 case in group B were irradiated by WBRT+SIB(3Gy*10Fx for WBRT and the same 4Gy*10Fx for BMs).All patients had complete MMSE scores before radiotherapy,at the end of radiotherapy,1 month after radiotherapy,3 months after radiotherapy,and 6 months after radiotherapy.The efficacy and differences in cognitive impairment were compared between the two groups.Results: The Cumulative survival rates of 1,2 and 3 years in 52 patients were 52.5%,28.6% and 14.3%,respectively.The median survival time was 13 months.The Cumulative 1,2 and 3-year survival rates of group A were 60.0%,41.1%,27.4%,respectively.The median survival time was 15 months.The 1,2 and 3-year survival rates of group B were 47.8%,19.1%,0%,respectively.The median survival time was 10 months.The effect difference between group A and B was significant(P=0.046).Subgroup analysis revealed that 1,2 and 3 years survival rate and median survival time of group A were significantly superior to group B,especially to those patients with 1-2 BMs,male or age <60 years old(P<0.05).MMSE scores at the end of radiation and at 1 month after radiation were not significantly different from those before treatment in both group(P>0.05),however,the scores at 3 or 6 months after radiation were lower than before radiation,the difference was significant(P<0.05).There was no significant difference in MMSE scores in the two group before radiation,at the end of radiation,at 1 month after radiation and at 6 months after radiation(P> 0.05).The scores of group A at 3 months after radiation was higher than that of group B(P<0.05).Certainly,group A had longer radiotherapy time and more cost than group B(P<0.005).Conclusions: For limited number of BMs in non-small cell lung cancer,WBRT+SEB is better than WBRT+SIB,especially to 1-2 metastases,male or aged <60 years patients.Three months after treatment,the cognitive function of brain neurons decreased in both groups,but in the WBRT+SEB group,the decline was relatively mild.