title: Whole brain radiotherapy plus simultaneous in-field boost with image guided intensity-modulated radiotherapy for brain metastases of non-small cell lung cancer.
abstract: BACKGROUND
  Whole brain radiotherapy (WBRT) plus sequential focal radiation boost is a commonly used therapeutic strategy for patients with brain metastases. However, recent reports on WBRT plus simultaneous in-field boost (SIB) also showed promising outcomes. The objective of present study is to retrospectively evaluate the efficacy and toxicities of WBRT plus SIB with image guided intensity-modulated radiotherapy (IG-IMRT) for inoperable brain metastases of NSCLC.
  
  
  METHODS
  Twenty-nine NSCLC patients with 87 inoperable brain metastases were included in this retrospective study. All patients received WBRT at a dose of 40 Gy/20 f, and SIB boost with IG-IMRT at a dose of 20 Gy/5 f concurrent with WBRT in the fourth week. Prior to each fraction of IG-IMRT boost, on-line positioning verification and correction were used to ensure that the set-up errors were within 2 mm by cone beam computed tomography in all patients.
  
  
  RESULTS
  The one-year intracranial control rate, local brain failure rate, and distant brain failure rate were 62.9%, 13.8%, and 19.2%, respectively. The two-year intracranial control rate, local brain failure rate, and distant brain failure rate were 42.5%, 30.9%, and 36.4%, respectively. Both median intracranial progression-free survival and median survival were 10 months. Six-month, one-year, and two-year survival rates were 65.5%, 41.4%, and 13.8%, corresponding to 62.1%, 41.4%, and 10.3% of intracranial progression-free survival rates. Patients with Score Index for Radiosurgery in Brain Metastases (SIR) >5, number of intracranial lesions <3, and history of EGFR-TKI treatment had better survival. Three lesions (3.45%) demonstrated radiation necrosis after radiotherapy. Grades 2 and 3 cognitive impairment with grade 2 radiation leukoencephalopathy were observed in 4 (13.8%) and 4 (13.8%) patients. No dosimetric parameters were found to be associated with these late toxicities. Patients received EGFR-TKI treatment had higher incidence of grades 2-3 cognitive impairment with grade 2 leukoencephalopathy.
  
  
  CONCLUSIONS
  WBRT plus SIB with IG-IMRT is a tolerable and effective treatment for NSCLC patients with inoperable brain metastases. However, the results of present study need to be examined by the prospective investigations.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhou
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Jianxin
authors.initials: J
authors.lastname: Xue
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.forename: Youling
authors.initials: Y
authors.lastname: Gong
authors.forename: Lei
authors.initials: L
authors.lastname: Deng
authors.forename: Shichao
authors.initials: S
authors.lastname: Wang
authors.forename: Renming
authors.initials: R
authors.lastname: Zhong
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Ding
authors.affiliation: Department of Thoracic Cancer, Cancer Center, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China. radyoulu@hotmail.com.
authors.forename: You
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D016371:Cranial Irradiation / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D056784:Leukoencephalopathies / Q000209:etiology*; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies