title: [Classification and regression tree analysis of clinical patterns that predict survival in 127 Chinese patients with advanced non-small cell lung cancer treated by gefitinib who failed to previous chemotherapy].
abstract: OBJECTIVE
  It has been proven that ge-tinib produces only 10%-20% tumor regression in heavily pretreated, unselected non-small cell lung cancer (NSCLC) patients as the second- and third-line se ing. Asian, female, nonsmokers and adenocarcinoma are favorable factors; however, it is difficult to -nd a patient satisfying all the above clinical characteristics. The aim of this study is to identify novel predicting factors, and to explore the interactions between clinical variables and their impact on the survival of Chinese patients with advanced NSCLC who were heavily treated with getinib in the second- or third-line setting.
  
  
  METHODS
  The clinical and follow-up data of 127 advanced NSCLC patients referred to the Cancer Hospital & Institute, Chinese Academy of Medical Sciences from March 2005 to March 2010 were analyzed. Multivariate analysis of progression-free survival (PFS) was performed using recursive partitioning, which is referred to as the classification and regression tree (CART) analysis.
  
  
  RESULTS
  The median PFS of 127 eligible consecutive advanced NSCLC patients was 8.0 months (95%CI: 5.8-10.2). CART was performed with an initial split on -rst-line chemotherapy outcomes and a second split on patients' age. Three terminal subgroups were formed. The median PFS of the three subsets ranged from 1.0 month (95%CI: 0.8-1.2) for those with progressive disease outcome after the -rst-line chemotherapy subgroup, 10 months (95%CI: 7.0-13.0) in patients with a partial response or stable disease in first-line chemotherapy and age < 70, and 22.0 months for patients obtaining a partial response or stable disease in first-line chemotherapy at age 70-81 (95%CI: 3.8-40.1).
  
  
  CONCLUSIONS
  Partial response, stable disease in first-line chemotherapy and age 70 are closely correlated with long-term survival treated by getinib as a second- or third-line se ing in advanced NSCLC. CART can be used to identify previously unappreciated patient subsets and is a useful method for dissecting complex clinical situations. Moreover, CART can be used to identify homogeneous patient populations in clinical practice and future clinical trials.
authors.affiliation: Department of Medical Oncology, Cancer Hospital & Institute, Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China. pingziwang@yahoo.com
authors.forename: Ziping
authors.initials: Z
authors.lastname: Wang
authors.forename: Jihong
authors.initials: J
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Yutao
authors.initials: Y
authors.lastname: Liu
authors.forename: Juan
authors.initials: J
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011799:Quinazolines / Q000494:pharmacology / Q000627:therapeutic use*; D012044:Regression Analysis; D012189:Retrospective Studies; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D011799:Quinazolines; D000077156:Gefitinib