title: Classification tree analysis of second neoplasms in survivors of childhood cancer.
abstract: BACKGROUND
  Reports on childhood cancer survivors estimated cumulative probability of developing secondary neoplasms vary from 3.3% to 25% at 25 years from diagnosis, and the risk of developing another cancer to several times greater than in the general population.
  
  
  METHODS
  In our retrospective study, we have used the classification tree multivariate method on a group of 849 first cancer survivors, to identify childhood cancer patients with the greatest risk for development of secondary neoplasms.
  
  
  RESULTS
  In observed group of patients, 34 develop secondary neoplasm after treatment of primary cancer. Analysis of parameters present at the treatment of first cancer, exposed two groups of patients at the special risk for secondary neoplasm. First are female patients treated for Hodgkin's disease at the age between 10 and 15 years, whose treatment included radiotherapy. Second group at special risk were male patients with acute lymphoblastic leukemia who were treated at the age between 4.6 and 6.6 years of age.
  
  
  CONCLUSIONS
  The risk groups identified in our study are similar to the results of studies that used more conventional approaches. Usefulness of our approach in study of occurrence of second neoplasms should be confirmed in larger sample study, but user friendly presentation of results makes it attractive for further studies.
authors.affiliation: Division of oncology and hematology, Department of Pediatrics, Medical Center, Vrazov trg 1, Ljubljana, Slovenia. janez.jazbec@mf.uni-lj.si
authors.forename: Janez
authors.initials: J
authors.lastname: Jazbec
authors.forename: Ljupco
authors.initials: L
authors.lastname: Todorovski
authors.forename: Berta
authors.initials: B
authors.lastname: Jereb
mesh_terms: D000293:Adolescent; D002648:Child; D005500:Follow-Up Studies; D006801:Humans; D015999:Multivariate Analysis; D009369:Neoplasms / Q000145:classification / Q000503:physiopathology*; D016609:Neoplasms, Second Primary / Q000145:classification / Q000453:epidemiology*; D011336:Probability; D012042:Registries; D012189:Retrospective Studies; D017524:Slovenia / Q000453:epidemiology; D017741:Survivors