title: The impact of N-ratio in minimizing stage migration phenomenon in gastric cancer patients with insufficient number or level of lymph node retrieved: results from a Chinese mono-institutional study in 2159 patients.
abstract: BACKGROUND
  Previous studies indicate that N-ratio has significant superiority in minimizing 'stage migration' for patients with >15 lymph nodes retrieved. Whether the result is applicable to patients with < or =15 lymph nodes retrieved is still in question.
  
  
  METHODS
  Overall survival rates of 2159 gastric cancer patients who underwent radical resection were compared between patients with different number and level of lymph nodes retrieved according to pN [International Union Against Cancer (Union Internationale Contre le Cancer)/AJCC N stage], n (JGCA N stage) and rN (N-ratio) staging system.
  
  
  RESULTS
  Patient number was significantly different between insufficient and sufficient number or level retrieved group in pN and n system, respectively, but not in rN system, while overall survival rates were not significantly different between those groups. The 5-year survival rates of patients with insufficient nodes retrieved were significantly lower than those with sufficient nodes retrieved in pN and n system, but not in rN system. The hazard risk for patients with insufficient nodes retrieved was significantly higher than that for patients with sufficient nodes retrieved in pN and n system, but not in rN system.
  
  
  CONCLUSIONS
  The rN stage has more potential advantages in minimizing stage migration phenomenon for patients with insufficient number or level of lymph nodes retrieved.
authors.affiliation: Department of Surgical Oncology, First Affiliated Hospital of China Medical University, Shenyang, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Sun
authors.forename: G-L
authors.initials: GL
authors.lastname: Zhu
authors.forename: C
authors.initials: C
authors.lastname: Lu
authors.forename: P-T
authors.initials: PT
authors.lastname: Guo
authors.forename: B-J
authors.initials: BJ
authors.lastname: Huang
authors.forename: K
authors.initials: K
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Li
authors.forename: Z-N
authors.initials: ZN
authors.lastname: Wang
authors.forename: H-M
authors.initials: HM
authors.lastname: Xu
mesh_terms: D002681:China; D005743:Gastrectomy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008197:Lymph Node Excision; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome