title: Multicenter validation of two nomograms to predict non-sentinel node involvement in breast cancer.
abstract: BACKGROUND
  Nomograms are used to predict the involvement of non-sentinel nodes (nSN) in breast cancer. This study attempts to externally validate two of the more commonly used nomograms (MSKCC and Stanford University).
  
  
  METHODS
  Five hundred and one cases of positive SNB with posterior axillary lymphadenectomy from 11 Spanish hospitals with widespread experience of the technique were studied. In all cases, an estimate of the probability of nSN involvement was made using the MSKCC and the Stanford University nomograms. Discrimination was assessed by calculating the area under the receiver operating characteristic curve. To assess the calibration of the nomogram, observed probability was plotted against the nomogram-calculated predicted probability.
  
  
  RESULTS
  The overall predictive accuracy of the MSKCC nomogram was 0.684 (95 % confidence interval, 0.635-0.732), while in the case of that from Stanford the predictive accuracy was 0.658 (95 % confidence interval 0.607-0.709). The mean predicted probability of nSN metastases in each group of patients was correlated with the observed probability with an acceptable concordance (r = 0.820; p < 0.004 in MSKCC nomogram and r = 0.888; p < 0.001 in Stanford nomogram).
  
  
  CONCLUSIONS
  These nomograms can be useful tools in the evaluation of patients with breast cancer and positive sentinel nodes but other factors, including a comprehensive clinical assessment, must be used to decide the most appropriate surgical approach for an individual patient, especially with regard to avoiding unnecessary lymphadenectomy.
authors.affiliation: Department of General Surgery, Virgen de la Arrixaca University Hospital, 30120, Murcia, Spain. antonio.pinero@carm.es
authors.forename: Antonio
authors.initials: A
authors.lastname: Piñero
authors.forename: Manuel
authors.initials: M
authors.lastname: Canteras
authors.forename: Arancha
authors.initials: A
authors.lastname: Moreno
authors.forename: Francisco
authors.initials: F
authors.lastname: Vicente
authors.forename: Julia
authors.initials: J
authors.lastname: Giménez
authors.forename: Ana
authors.initials: A
authors.lastname: Tocino
authors.forename: Edelmiro
authors.initials: E
authors.lastname: Iglesias
authors.forename: Sergi
authors.initials: S
authors.lastname: Vidal-Sicart
authors.forename: Luzdivina
authors.initials: L
authors.lastname: Santamaría
authors.forename: Miguel
authors.initials: M
authors.lastname: Lorenzo
authors.forename: Manuel
authors.initials: M
authors.lastname: García
authors.forename: Diego
authors.initials: D
authors.lastname: Ramirez
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008875:Middle Aged; D049451:Nomograms; D012372:ROC Curve; D021701:Sentinel Lymph Node Biopsy