title: [Clinical verification of a mathematical model for prediction of brain metastases in patients with locally advanced non-small cell lung cancer.].
abstract: BACKGROUND
  Brain metastases are the main determining factor in the failure of patients with locally advanced non-small cell lung cancer (LA-NSCLC) by multimodality treatments. Whether we can use PCI to the patients with NSCLC and how to screen out high-risk patients are still controversial. We have reported a mathematical model, through which we can predict high-risk brain metastases in patients with postoperative LA-NSCLC. The purpose of this study is to verify the accuracy of the mathematical model, using new cases information.
  
  
  METHODS
  A total of 196 patients of stage III NSCLC treated with surgical resection were retrospectively analyzed, to verify the consistency between actual and predictive brain metastases.
  
  
  RESULTS
  The median survival time after surgery for all patients was 32.1 months. The one-, two- and three- year survival rate were 84.7%, 63.9%, 51.7%. The incidence rate of brain metastases was 42.3% (83/196). The incidence rate of brain metastases as the first site of recurrence was 28.1% (55/196). Results of accuracy of the mathematical model were sensitivity of 84.3%, specificity of 64.6%, positive predictive value of 63.6% and a negative predictive value of 84.9%, Measure of agreement Kappa value of 0.47 (P <0.001).
  
  
  CONCLUSIONS
  The mathematical model can predict brain metastases high risk patients with LA-NSCLC after surgery. It can be used as a basis to screening out patients of high risk brain metastases in future clinical trails about PCI.
authors: Thoracic Department, Cancer Center of Sun Yat-sen University, GuangzhouGuangdong 510060, China.
authors: Binbin
authors: B
authors: Zhang
authors: Siyu
authors: S
authors: Wang
authors: Wei
authors: W
authors: Qu
authors: Yongbin
authors: Y
authors: Lin
authors: Hua
authors: H
authors: Yang
authors: Haibo
authors: H
authors: Sun