title: Risk factors of brain metastases in completely resected pathological stage IIIA-N2 non-small cell lung cancer.
abstract: BACKGROUND
  Brain metastases (BM) is one of the most common failures of locally advanced non-small cell lung cancer (LA-NSCLC) after combined-modality therapy. The outcome of trials on prophylactic cranial irradiation (PCI) has prompted us to identify the highest-risk subset most likely to benefit from PCI. Focusing on patients with completely resected pathological stage IIIA-N2 (pIIIA-N2) NSCLC, we aimed to assess risk factors of BM and to define the highest-risk subset.
  
  
  METHODS
  Between 2003 and 2005, the records of 217 consecutive patients with pIIIA-N2 NSCLC in our institution were reviewed. The cumulative incidence of BM was estimated using the Kaplan-Meier method, and differences between the groups were analyzed using log-rank test. Multivariate Cox regression analysis was applied to assess risk factors of BM.
  
  
  RESULTS
  Fifty-three (24.4 %) patients developed BM at some point during their clinical course. On multivariate analysis, non-squamous cell cancer (relative risk [RR]: 4.13, 95 % CI: 1.86-9.19; P = 0.001) and the ratio of metastatic to examined nodes or lymph node ratio (LNR) ≥ 30 % (RR: 3.33, 95 % CI: 1.79-6.18; P = 0.000) were found to be associated with an increased risk of BM. In patients with non-squamous cell cancer and LNR ≥ 30 %, the 5-year actuarial risk of BM was 57.3 %.
  
  
  CONCLUSIONS
  In NSCLC, patients with completely resected pIIIA-N2 non-squamous cell cancer and LNR ≥ 30 % are at the highest risk for BM, and are most likely to benefit from PCI. Further studies are warranted to investigate the effect of PCI on this subset of patients.
authors: Department of Radiation Oncology, Cancer Hospital & Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Chao yang District, Beijing, China.
authors: Xiao
authors: X
authors: Ding
authors: Honghai
authors: H
authors: Dai
authors: Zhouguang
authors: Z
authors: Hui
authors: Wei
authors: W
authors: Ji
authors: Jun
authors: J
authors: Liang
authors: Jima
authors: J
authors: Lv
authors: Zongmei
authors: Z
authors: Zhou
authors: Weibo
authors: W
authors: Yin
authors: Jie
authors: J
authors: He
authors: Luhua
authors: L
authors: Wang
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000556:secondary*; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D012307:Risk Factors