title: Recursive partitioning analysis for new classification of patients with esophageal cancer treated by chemoradiotherapy.
abstract: BACKGROUND
  The 7th edition of the American Joint Committee on Cancer staging system does not include lymph node size in the guidelines for staging patients with esophageal cancer. The objectives of this study were to determine the prognostic impact of the maximum metastatic lymph node diameter (ND) on survival and to develop and validate a new staging system for patients with esophageal squamous cell cancer who were treated with definitive chemoradiotherapy (CRT).
  
  
  METHODS
  Information on 402 patients with esophageal cancer undergoing CRT at two institutions was reviewed. Univariate and multivariate analyses of data from one institution were used to assess the impact of clinical factors on survival, and recursive partitioning analysis was performed to develop the new staging classification. To assess its clinical utility, the new classification was validated using data from the second institution.
  
  
  RESULTS
  By multivariate analysis, gender, T, N, and ND stages were independently and significantly associated with survival (p < 0.05). The resulting new staging classification was based on the T and ND. The four new stages led to good separation of survival curves in both the developmental and validation datasets (p < 0.05).
  
  
  CONCLUSIONS
  Our results showed that lymph node size is a strong independent prognostic factor and that the new staging system, which incorporated lymph node size, provided good prognostic power, and discriminated effectively for patients with esophageal cancer undergoing CRT.
authors.affiliation: Department of Radiology, Kansai Medical University, Hirakata, Japan; Department of Clinical Oncology, Aichi Cancer Center Hospital, Nagoya, Japan. excell@hkg.odn.ne.jp
authors.forename: Motoo
authors.initials: M
authors.lastname: Nomura
authors.forename: Kohei
authors.initials: K
authors.lastname: Shitara
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kodaira
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kondoh
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takahari
authors.forename: Takashi
authors.initials: T
authors.lastname: Ura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kojima
authors.forename: Minoru
authors.initials: M
authors.lastname: Kamata
authors.forename: Kei
authors.initials: K
authors.lastname: Muro
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sawada
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D059248:Chemoradiotherapy / Q000379:methods; D004938:Esophageal Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging / Q000379:methods*; D011379:Prognosis; D011879:Radiotherapy Dosage; D012737:Sex Factors; D047368:Tumor Burden