title: Negative lymph node count is an independent prognostic factor for patients with rectal cancer who received preoperative radiotherapy.
abstract: Negative lymph node (NLN) count has been reported to provide more accurate prognostic information than the N stage alone in patients with rectal cancer (RC). Since preoperative radiotherapy (Pre-RT) can significantly affect the LN status, it is unclear whether NLN count still has prognostic value count on survival of patients with RC who received Pre-RT.
  
  
  
  In this study, clinicopathological characteristics, number of positive LNs and survival time were collected from Surveillance, Epidemiology, and End Results Program (SEER)-registered RC patients. Univariate and multivariate Cox proportional hazards models were used to assess the risk factors for survival.
  
  
  
  X-tile plots identified 9 (P < 0.001) as the optimal cutoff NLN value to divide the patients into high and low risk subsets in terms of cause specific survival (CSS). NLN count was validated as independently prognostic factor in univariate and multivariate analysis (P < 0.001). Subgroup analysis showed that NLN count was an independently prognostic factor for patients with stage ypII (P = 0.002) and ypIII (P < 0.001).
  
  
  
  Our results firmly demonstrated that NLN count provides accurate prognostic information for RC patients with Pre-RT.
authors.affiliation: Department of General Surgery, Changzheng Hospital, The Second Military Medical University, 415 S. Fengyang Road, Shanghai, 200003, China.
authors.forename: Xinxing
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of General Surgery, Changzheng Hospital, The Second Military Medical University, 415 S. Fengyang Road, Shanghai, 200003, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Lu
authors.affiliation: Department of General Surgery, Changzheng Hospital, The Second Military Medical University, 415 S. Fengyang Road, Shanghai, 200003, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
authors.affiliation: Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD, 4102, Australia.
authors.forename: Haolu
authors.initials: H
authors.lastname: Wang
authors.affiliation: Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD, 4102, Australia. x.liang@uq.edu.au.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Liang
authors.affiliation: Department of General Surgery, Changzheng Hospital, The Second Military Medical University, 415 S. Fengyang Road, Shanghai, 200003, China. huzhiq163@163.com.
authors.forename: Zhiqian
authors.initials: Z
authors.lastname: Hu
mesh_terms: D000230:Adenocarcinoma / Q000532:radiotherapy / Q000556:secondary*; D002288:Adenocarcinoma, Mucinous / Q000532:radiotherapy / Q000556:secondary*; D018279:Carcinoma, Signet Ring Cell / Q000532:radiotherapy / Q000556:secondary*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011300:Preoperative Care; D011379:Prognosis; D011878:Radiotherapy; D012004:Rectal Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D018426:SEER Program; D015996:Survival Rate
keywords: Negative lymph node; Preoperative radiotherapy; Rectal cancer; Survival