title: A clinical nomogram predicting pathologic lymph node involvement in esophageal cancer patients.
abstract: BACKGROUND
  Esophageal cancer patients with pathologic lymph-node involvement (pN1) generally have a poor prognosis with surgery alone. We, therefore, constructed a nomogram to predict the risk of pN1 prior to surgical resection and externally validated the clinical utility of the model.
  
  
  METHODS
  A total of 273 esophageal adenocarcinoma patients treated with surgery alone were reviewed from 2 different institutions (University of Texas M. D. Anderson Cancer Center = 164, training set; University of Rochester School of Medicine and Dentistry = 109, validation set). Pretreatment clinical parameters were used to construct a nomogram for predicting the risk of pN1. Internal and external validation of the nomogram was performed to assess clinical utility.
  
  
  RESULTS
  Of the 164 patients in the training set, 56 patients (34%) had lymph-node involvement (pN1). Significant factors associated with pN1 on univariable logistic regression analysis (using a P < 0.05) included endoscopically determined clinical tumor depth (cT), clinical nodal (cN) status, and clinical tumor length (cL). Multivariable analysis suggested the significant independent factors were cT (odds ratio, 5.6; 95% confidence interval, 1.7-18.6; P < 0.01) and cL >2 cm (odds ratio, 7.0; 95% confidence interval, 2.7-18.1; P < 0.001). Regression tree analysis was used to determine the best cutoff for cL. A nomogram was created for pN1 using these clinical parameters and was internally validated by bootstrapping with a predicted accuracy of 85.1%. External validation performed on the validation set demonstrated an original C-index of 0.777 suggesting good clinical utility.
  
  
  CONCLUSIONS
  Our analyses demonstrate that the risk of pathologic nodal involvement in esophageal adenocarcinoma patients can be estimated by this clinical nomogram, which will allow the identification of patients at high-risk of harboring positive lymph-nodes, who may be candidates for en bloc resection and/or neoadjuvant treatment.
authors.affiliation: Department of Surgical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Puja
authors.initials: P
authors.lastname: Gaur
authors.forename: Boris
authors.initials: B
authors.lastname: Sepesi
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Hofstetter
authors.forename: Arlene M
authors.initials: AM
authors.lastname: Correa
authors.forename: Manoop S
authors.initials: MS
authors.lastname: Bhutani
authors.forename: Ara A
authors.initials: AA
authors.lastname: Vaporciyan
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Watson
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Swisher
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004938:Esophageal Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods