title: Positive lymph node ratio is an independent prognostic factor in gastric cancer after d2 resection regardless of the examined number of lymph nodes.
abstract: The purpose of this study was to clarify the outcome of the ratio between metastatic and examined lymph nodes (N ratio) in gastric cancer patients with < or =15 examined lymph nodes after D2 lymphadenectomy. A retrospective study was performed in 906 patients with gastric cancer who had undergone D2 resection. Patients with < or =15 examined lymph nodes (group 1, n = 729) and those with >15 lymph nodes (group 2, n = 177) were analyzed separately. N ratio categories were identified as follows: N ratio 0, 0%; N ratio 1, 1% to 9%; N ratio 2, 10% to 25%; N ratio 3, >25%. Univariate analysis found that both the tumor, node, metastasis system (N staging system) and N ratio system well classified patients with significantly different prognosis. By multivariate analysis, only the N ratio classification was retained as an independent prognostic factor in both group 1 and 2 compared with the N stage system. Furthermore, when patients were divided into four groups according to the number of lymph nodes examined (1 to 3, 4 to 7, 8 to 11, and 12 to 15), the 5-year survival rates remained similar between groups according to the same N ratio (p > .05). Positive N ratio classification is a better prognostic tool compared with N staging system after D2 resection in patients with gastric cancer. It can prevent stage migration and can be used regardless of the examined number of lymph nodes.
authors.affiliation: State Key Laboratory of Oncology in South China, Guangzhou. xdz1976@yahoo.com.cn
authors.forename: Da-zhi
authors.initials: DZ
authors.lastname: Xu
authors.forename: Qi-rong
authors.initials: QR
authors.lastname: Geng
authors.forename: Zi-jie
authors.initials: ZJ
authors.lastname: Long
authors.forename: You-qing
authors.initials: YQ
authors.lastname: Zhan
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Zhi-wei
authors.initials: ZW
authors.lastname: Zhou
authors.forename: Ying-bo
authors.initials: YB
authors.lastname: Chen
authors.forename: Xiao-wei
authors.initials: XW
authors.lastname: Sun
authors.forename: Gong
authors.initials: G
authors.lastname: Chen
authors.forename: Quentin
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D009367:Neoplasm Staging; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery*; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult