Temozolomide Combine With Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost for Non Small Cell Lung Cancer Brain Metastases

With the improvement of systemic therapeutic effect(especially in the population with driver gene mutation), the incidence of brain metastases had significantly increased. Conventional Whole Brain radiotherapy(WBRT) was less effective, the stereotactic radiosurgery(SRS) technique had improve the local efficacy for 1-3 lesions, but the probability of intracranial recurrence was increased, Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost(SIB-IMRT) is a new radiotherapy technology, Giving a standard radiation dose of whole brain ,at the same time can boost the high-risk region in target, So that it can significantly shorten the treatment time, at the same time can improve the local control rate of brain metastases. In the aspect of normal tissue protecting, SIB was better than WBRT plus SRS sequential treatment pattern. 30Gy to the whole brain had a negative effects on cognitive function, the investigators previous study found that 25Gy to the whole brain while the tumor bed Simultaneous push to 50Gy was safe and effective, while reducing the impact on cognitive function. Hippocampus is a part of the brain located in the temporal lobe, Mainly responsible for long-term memory storage conversion and orientation. Many investigators point out that hippocampus is the main commander of neurocognitive function, Reduce the dose of hippocampus can significant improve the neurocognitive function. Temozolomide capsule is an anti-tumor alkylation agent for glioblastoma multiforme and anaplastic astrocytoma. In recent years, some researchers find that Temozolomide capsules combine with radiotherapy such as SRS, WBRT or The two combined, can improve Objective response(OR) and prolong the Progress Free Survival(PFS),while with tolerable therapeutic toxicity. In order to better reduce the impact on cognitive function and improve the local control rate, the investigators present this trial, under the SIB-IMRT technique, the investigators want to explore the effe