title: A novel clinical prognostic score incorporating the number of resected lymph-nodes to predict recurrence and survival in non-small-cell lung cancer.
abstract: BACKGROUND
  The number of resected lymph-nodes (#RNs) has proven prognostic in breast and colorectal cancer. Here we evaluated its prognostic impact in a series of resected NSCLC patients.
  
  
  METHODS
  A panel of established prognostic factors plus (1) #RNs or (2) the ratio between the number of metastatic nodes and #RNs (NR) were correlated to overall- (OS), cancer-specific- (CSS), and disease-free-survival (DFS), using the Cox-model. Risk-classes according to hazard ratios (HR) were generated. Internal and external validation was accomplished.
  
  
  RESULTS
  A dataset of 415 resected NSCLC patients was retrieved. At multivariate analysis, #RNs and NR were independent factor for longer OS, CSS and DFS (p<0.0001). Patients with a #RNs>10 (identified optimal cut-off) had a statistically significant OS (p=0.02) and DFS (p=0.0005) benefit. In node-positive patients, a NR<9% significantly correlated with better outcome. Stratification into High-, Medium-, and Low-Risk classes, based on High- (HRFs: stage, N-status, age, #RNs) and Intermediate-Risk Factors (IRFs: sex, grading, histology), efficiently predicted outcomes (p<0.0001). The risk class model performance was externally validated in and independent dataset of 297 patients.
  
  
  CONCLUSIONS
  These results contribute to complete the panel of prognostic factors for resected NSCLC. A prospective larger validation and comparison with molecular prognostic tools is warranted.
authors.affiliation: Department of Medical Oncology, Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy. emiliobria@yahoo.it
authors.forename: Emilio
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authors.lastname: Bria
authors.forename: Michele
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authors.lastname: Milella
authors.forename: Isabella
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authors.lastname: Sperduti
authors.forename: Gabriele
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authors.lastname: Alessandrini
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authors.lastname: Visca
authors.forename: Felicita
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authors.lastname: Corzani
authors.forename: Diana
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authors.lastname: Giannarelli
authors.forename: Virna
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authors.lastname: Cerasoli
authors.forename: Federica
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authors.lastname: Cuppone
authors.forename: Fabiana Letizia
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authors.lastname: Cecere
authors.forename: Antonio
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authors.lastname: Marchetti
authors.forename: Rocco
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authors.lastname: Sacco
authors.forename: Felice
authors.initials: F
authors.lastname: Mucilli
authors.forename: Sara
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authors.lastname: Malatesta
authors.forename: Luigi
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authors.lastname: Guetti
authors.forename: Luca
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authors.lastname: Vitale
authors.forename: Anna
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authors.lastname: Ceribelli
authors.forename: Massimo
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authors.lastname: Rinaldi
authors.forename: Edmondo
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authors.lastname: Terzoli
authors.forename: Francesco
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authors.lastname: Cognetti
authors.forename: Francesco
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authors.lastname: Facciolo