title: Classification and regression tree (CART) analysis of endometrial carcinoma: Seeing the forest for the trees.
abstract: OBJECTIVE
  The objectives of the study are to evaluate which clinicopathologic factors influenced overall survival (OS) in endometrial carcinoma and to determine if the surgical effort to assess para-aortic (PA) lymph nodes (LNs) at initial staging surgery impacts OS.
  
  
  METHODS
  All patients diagnosed with endometrial cancer from 1/1993-12/2011 who had LNs excised were included. PALN assessment was defined by the identification of one or more PALNs on final pathology. A multivariate analysis was performed to assess the effect of PALNs on OS. A form of recursive partitioning called classification and regression tree (CART) analysis was implemented. Variables included: age, stage, tumor subtype, grade, myometrial invasion, total LNs removed, evaluation of PALNs, and adjuvant chemotherapy.
  
  
  RESULTS
  The cohort included 1920 patients, with a median age of 62 years. The median number of LNs removed was 16 (range, 1-99). The removal of PALNs was not associated with OS (P=0.450). Using the CART hierarchically, stage I vs. stages II-IV and grades 1-2 vs. grade 3 emerged as predictors of OS. If the tree was allowed to grow, further branching was based on age and myometrial invasion. Total number of LNs removed and assessment of PALNs as defined in this study were not predictive of OS.
  
  
  CONCLUSIONS
  This innovative CART analysis emphasized the importance of proper stage assignment and a binary grading system in impacting OS. Notably, the total number of LNs removed and specific evaluation of PALNs as defined in this study were not important predictors of OS.
authors.affiliation: Gynecology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Joyce N
authors.initials: JN
authors.lastname: Barlin
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhou
authors.forename: Caryn M
authors.initials: CM
authors.lastname: St Clair
authors.forename: Alexia
authors.initials: A
authors.lastname: Iasonos
authors.forename: Robert A
authors.initials: RA
authors.lastname: Soslow
authors.forename: Kaled M
authors.initials: KM
authors.lastname: Alektiar
authors.forename: Martee L
authors.initials: ML
authors.lastname: Hensley
authors.forename: Mario M
authors.initials: MM
authors.lastname: Leitao
authors.forename: Richard R
authors.initials: RR
authors.lastname: Barakat
authors.forename: Nadeem R
authors.initials: NR
authors.lastname: Abu-Rustum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta; D002277:Carcinoma / Q000556:secondary* / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D016889:Endometrial Neoplasms / Q000473:pathology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant; D012044:Regression Analysis; D012189:Retrospective Studies; D055815:Young Adult
keywords: CART analysis; Classification and regression tree analysis; Endometrial cancer; Lymph nodes; Overall survival; Staging