title: Nomogram for predicting pathologically complete response after neoadjuvant chemoradiotherapy for oesophageal cancer.
abstract: BACKGROUND
  A pathologically complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) is seen in 30% of the patients with oesophageal cancer. The aim is to identify patient and tumour characteristics associated with a pCR and to develop a nomogram for the prediction of pCR.
  
  
  METHODS
  Patients who underwent nCRT followed by surgery were identified and response to nCRT was assessed according to a modified Mandard classification in the resection specimen. A model was developed with age, gender, histology and location of the tumour, differentiation grade, alcohol use, smoking, percentage weight loss, Charlson Comorbidity Index (CCI), cT-stage and cN-stage as potential predictors for pCR. Probability of pCR was studied via logistic regression. Performance of the prediction nomogram was quantified using the concordance statistic (c-statistic) and corrected for optimism.
  
  
  RESULTS
  A total of 381 patients were included. After surgery, 27.6% of the tumours showed a pCR. Female sex, squamous cell histology, poor differentiation grade, and low cT-stage were predictive for a pCR with a c-statistic of 0.64 (corrected for optimism).
  
  
  CONCLUSIONS
  A nomogram for the prediction of pathologically complete response after neoadjuvant chemoradiotherapy was developed, with a reasonable predictive power. This nomogram needs external validation before it can be used for individualised clinical decision-making.
authors.affiliation: Department of Surgery, Erasmus MC, University Medical Centre Rotterdam, The Netherlands. Electronic address: e.toxopeus@erasmusmc.nl.
authors.forename: Eelke Lucie Anne
authors.initials: EL
authors.lastname: Toxopeus
authors.affiliation: Centre for Medical Decision Making, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Daan
authors.initials: D
authors.lastname: Nieboer
authors.affiliation: Department of Surgery, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Joel
authors.initials: J
authors.lastname: Shapiro
authors.affiliation: Department of Pathology, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Katharina
authors.initials: K
authors.lastname: Biermann
authors.affiliation: Department of Medical Oncology, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Ate
authors.initials: A
authors.lastname: van der Gaast
authors.affiliation: Department of Radiation Oncology, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Carolien M
authors.initials: CM
authors.lastname: van Rij
authors.affiliation: Centre for Medical Decision Making, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Ewout Willem
authors.initials: EW
authors.lastname: Steyerberg
authors.affiliation: Department of Surgery, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Joseph Jan Baptiste
authors.initials: JJ
authors.lastname: van Lanschot
authors.affiliation: Department of Surgery, Erasmus MC, University Medical Centre Rotterdam, The Netherlands.
authors.forename: Bas Peter Louis
authors.initials: BP
authors.lastname: Wijnhoven
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D004938:Esophageal Neoplasms / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D049451:Nomograms; D012074:Remission Induction; D055815:Young Adult
keywords: Neoadjuvant chemoradiotherapy; Oesophageal cancer; Prediction of response; Surgery