title: Impact of Lateral Pelvic Lymph Node Dissection on the Survival of Patients with T3 and T4 Low Rectal Cancer.
abstract: BACKGROUND
  The aim of this study was to clarify the survival benefit of lateral pelvic lymph node dissection (LPLND) for patients with pathological T3 and T4 (pT3/T4) low rectal cancer.
  
  
  METHODS
  We evaluated the impact of LPLND on survival for pT3/T4 low rectal cancer patients. The primary endpoint of the study was overall survival (OS). The large-scale database of the Japanese Society for Cancer of the Colon and Rectum registration system was accessed and the data were analyzed using a propensity score matching method based on the likelihood of receiving LPLND. Using seven covariates, the propensity scores were calculated with multivariate logistic regression. A total of 499 propensity score-matched pairs of patients were selected from the entire cohort of 1,840 patients who had received curative resection for pT3/T4 low rectal cancer between 1995 and 2004.
  
  
  RESULTS
  In the matched cohort, the 5-year OS of the patients who had and had not undergone LPLND were 68.9 and 62.0 %, respectively (p = 0.013; hazard ratio [HR], 0.755; 95 % confidence interval [CI], 0.604-0.944). The 5-year OS of the patients with node-negative disease who had and had not received LPLND differed statistically significantly (5-year OS were 82.1 and 71.4 %, respectively. p = 0.006; HR, 0.579; 95 % CI 0.389-0.862). However, those with node-positive disease did not differ significantly (5-year OS were 55.5 and 53.8 %, respectively. p = 0.415; HR 0.893; 95 % CI 0.681-1.172).
  
  
  CONCLUSIONS
  The impact of LPLND on OS for patients with node-negative pT3/T4 low rectal cancer was suggested in this retrospective cohort study. To determine true benefits and harms of LPLND, further prospective studies may be warranted.
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan. heiozawa@tcc.pref.tochigi.lg.jp.
authors.forename: Heita
authors.initials: H
authors.lastname: Ozawa
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kotake
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Hosaka
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Hirata
authors.affiliation: Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, 113-8519, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugihara
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010388:Pelvis; D057216:Propensity Score; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies; D015996:Survival Rate