title: Prognostic impact of the number of retrieved lymph nodes in patients with gastric cancer.
abstract: BACKGROUND
  In gastric cancer, although at least 16 lymph nodes of retrieved lymph nodes (RLNs) are recommended for nodal staging in Japanese Classification of Gastric Carcinoma and TNM classifications, we wished to clarify their appropriateness.
  
  
  METHODS
  A total of 1289 consecutive gastric cancer patients, who underwent gastrectomy between 1997 and 2011, were analyzed retrospectively.
  
  
  RESULTS
  (i) The patients were divided into two groups using a cut-off RLN number of 16 (RLN < 16 or RLN ≥ 16). There were significant differences in the survival rates of patients in pStage II (P < 0.0001) and III (P = 0.0009), but not those of patients in pStage I (P = 0.0627) and IV (P = 0.1553). (ii) In 498 consecutive patients in pStage II and III, compared with patients in the RLN ≥ 16 group, those in the RLN < 16 group had a significantly higher incidence of older age (P = 0.0004) and positive lymph node ratio (PLNR) (P < 0.0001). Univariate and multivariate analyses showed that an RLN number of less than 16 was an independent poor prognostic factor (P < 0.0001, HR 2.48 [95% CI: 1.60-3.70]). (iii) A cut-off RLN number of 16 could cause the stage migration effect in pStage II or III patients. A cut-off RLN number of 25 or more could eliminate the prognostic effect.
  
  
  CONCLUSIONS
  The RLN number may potentially affect the prognosis and the stage migration in pStage II or III gastric cancer patients. An RLN number of 25 or more could be sufficient for nodal staging.
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Wataru
authors: W
authors: Okajima
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan. skomatsu@koto.kpu-m.ac.jp.
authors: Shuhei
authors: S
authors: Komatsu
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Daisuke
authors: D
authors: Ichikawa
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Toshiyuki
authors: T
authors: Kosuga
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Takeshi
authors: T
authors: Kubota
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Kazuma
authors: K
authors: Okamoto
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Hirotaka
authors: H
authors: Konishi
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Atsushi
authors: A
authors: Shiozaki
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Hitoshi
authors: H
authors: Fujiwara
authors: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors: Eigo
authors: E
authors: Otsuji
mesh_terms: D000368:Aged; D005260:Female; D005743:Gastrectomy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery
keywords: gastric cancer; positive lymph node ratio; prognosis; retrieved lymph node; stage migration