title: Lymph node ratio is a powerful prognostic index in patients with stage III distal rectal cancer: a Japanese multicenter study.
abstract: OBJECTIVE
  The present study aims to define the prognostic impact of the lymph node ratio (LNR) in patients with stage III distal rectal cancer.
  
  
  METHODS
  We analyzed data from 501 patients who underwent curative resection (total mesorectal excision, TME) for stage III distal rectal cancer at 12 institutions between 1991 and 1998. Patients were divided into four groups according to quartiles based on LNR.
  
  
  RESULTS
  Among the 501 patients, 381 underwent TME with pelvic sidewall dissection (PSD). The median numbers of lymph nodes retrieved with and without PSD were 45 and 17, respectively (P < 0.0001). Forty-nine patients with lymph node retrieved less than 12 were excluded from further analyses. Among various clinicopathological parameters, univariate analysis identified age (P = 0.0059), histological grade (P < 0.0001), depth of tumor invasion (P = 0.0003), and number of positive nodes (P < 0.0001) and LNR (P < 0.0001) as prognostic factors. The Cox proportional hazards model revealed that age (P = 0.014), histological grade (P < 0.0001), depth of tumor invasion (P = 0.0002), and LNR (group 3, P = 0.0012; group 4, P < 0.0001) were independent prognostic factors. When the American Joint Committee on Cancer (AJCC) seventh staging system was added as a covariate, both AJCC stage (P < 0.0001) and LNR (P < 0.0001) were independent prognostic factors.
  
  
  CONCLUSIONS
  Adding the LNR concept to the AJCC cancer staging system will improve accuracy in evaluating the nodal status of distal rectal cancer.
authors.affiliation: Department of Surgical Oncology, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan. h-kobayashi.srg2@tmd.ac.jp
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kato
authors.forename: Takeo
authors.initials: T
authors.lastname: Mori
authors.forename: Shingo
authors.initials: S
authors.lastname: Kameoka
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shirouzu
authors.forename: Yukio
authors.initials: Y
authors.lastname: Saito
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Takayuki
authors.initials: T
authors.lastname: Morita
authors.forename: Jin-Ichi
authors.initials: J
authors.lastname: Hida
authors.forename: Masashi
authors.initials: M
authors.lastname: Ueno
authors.forename: Masato
authors.initials: M
authors.lastname: Ono
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yasuno
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugihara
mesh_terms: D000368:Aged; D044466:Asian People; D004210:Dissection; D005260:Female; D006801:Humans; D007564:Japan; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D010388:Pelvis / Q000601:surgery; D011379:Prognosis; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D016019:Survival Analysis