title: Estimation of the number of metastatic lymph nodes in dukes' C colorectal cancer.
abstract: BACKGROUND
  Colorectal cancer staging is decided by the depth of tumor invasion and the node (N) category. Evaluation of the metastatic lymph node number (MLN) varies. The purpose of this study was to investigate the N-category as a function of MLN.
  
  
  METHODS
  Patients with colorectal cancer (n=551) who underwent curative resection were grouped based on the MLN, and appropriate cut-off values were decided based on survival. The validity of the new cut-off values was analyzed as a prognostic factor.
  
  
  RESULTS
  The median number of lymph nodes retrieved per patient was 19, and the median MLN was 2. The survival and recurrence rates allowed MLN groupings of 1-4, 5-7, and ≥8. In particular, when grouping was performed using MLN ≤4 and ≥5, the 5-year survival rate for patients with MLN ≥5 (56.8%) was significantly worse than that of these with MLN ≤4 (78.6%) (p<0.0001). Receiver operating characteristic (ROC) curve analysis showed the highest accuracy to be with MLN=5. Multivariate analysis using a Cox proportional hazard model identified MLN ≥5 as an independent adverse prognostic factor (hazard ratio=1.84; 95% confidence interval=1.2801-2.6295; p=0.0012).
  
  
  CONCLUSIONS
  MLN ≥5 is an independent predictor of 5-year survival for patients with Dukes' C colorectal cancer. It is possible that tumor staging in colorectal cancer differs between facilities, with particular ramifications for patients with stage III disease.
authors.affiliation: Department of Surgery, School of Medicine, Kurume University, Fukuoka, Japan.
authors.forename: Takanaru
authors.initials: T
authors.lastname: Fukushima
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Akagi
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Murakami
authors.forename: Masataka
authors.initials: M
authors.lastname: Ushijima
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ogata
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shirouzu
authors.forename: Kenta
authors.initials: K
authors.lastname: Murotani
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D000368:Aged; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery; D009367:Neoplasm Staging; D011379:Prognosis; D012372:ROC Curve; D015996:Survival Rate
keywords: Dukes' C; TNM classification; colorectal cancer; node category (N-category); retrieved lymph node number (RLN)