title: Lymph node ratio-based staging system for esophageal squamous cell carcinoma.
abstract: OBJECTIVE
  To analyze a modified staging system utilizing lymph node ratio (LNR) in patients with esophageal squamous cell carcinoma (ESCC).
  
  
  METHODS
  Clinical data of 2011 patients with ESCC who underwent surgical resection alone between January 1995 and June 2010 at the Cancer Hospital of Shantou University Medical College were reviewed. The LNR, or node ratio (Nr) was defined as the ratio of metastatic LNs ompared to the total number of resected LNs. Overall survival between groups was compared with the log-rank test. The cutoff point of LNR was established by grouping patients with 10% increment in Nr, and then combining the neighborhood survival curves using the log-rank test. A new TNrM staging system, was constructed by replacing the American Joint Committee on Cancer (AJCC) N categories with the Nr categories in the new TNM staging system. The time-dependent receiver operating characteristic curves were used to evaluate the predictive performance of the seventh edition AJCC staging system and the TNrM staging system.
  
  
  RESULTS
  The median number of resected LNs was 12 (range: 4-44), and 25% and 75% interquartile rangeswere8 and 16. Patients were classified into four Nr categories with distinctive survival differences (Nr0: LNR = 0; Nr1: 0% < LNR ≤ 10%; Nr2: 10% < LNR ≤ 20%; and Nr3: LNR > 20%). From N categories to Nr categories, 557 patients changed their LN stage. The median survival time (MST) for the four Nr categories (Nr0-Nr3) was 155.0 mo, 39.0 mo, 28.0 mo, and 19.0 mo, respectively, and the 5-year overall survival was 61.1%, 41.1%, 33.0%, and 22.9%, respectively (P < 0.001). Overall survival was significantly different for the AJCC N categories when patients were subgrouped into 15 or more vs fewer than 15 examined nodes, except for the N3 category (P = 0.292). However, overall survival was similar when the patients in all four Nr categories were subgrouped into 15 or more vs fewer than 15 nodes. Using the time-dependent receiver operating characteristic, we found that the Nr category and TNrM stage had higher accuracy in predicting survival than the AJCC N category and TNM stage.
  
  
  CONCLUSIONS
  A staging system based on LNR may have better prognostic stratification of patients with ESCC than the current TNM system, especially for those undergoing limited lymphadenectomy.
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Shao-Bin
authors.initials: SB
authors.lastname: Chen
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Hong-Rui
authors.initials: HR
authors.lastname: Weng
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Geng
authors.initials: G
authors.lastname: Wang
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Zou
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Di-Tian
authors.initials: DT
authors.lastname: Liu
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Chen
authors.affiliation: Shao-Bin Chen, Hong-Rui Weng, Geng Wang, Di-Tian Liu, Yu-Ping Chen, Department of Thoracic Surgery, Cancer Hospital of Shantou University Medical College, Shantou 515031, Guangdong Province, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000556:secondary* / Q000601:surgery; D004938:Esophageal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D000077277:Esophageal Squamous Cell Carcinoma; D016629:Esophagectomy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Cancer staging; Esophageal squamous cell carcinoma; Esophagectomy; Lymph node ratio; Prognosis