title: Impact of lymph node ratio and number on survival in patients with rectal adenocarcinoma after preoperative chemo radiation.
abstract: BACKGROUND
  Retrieval of <12 lymph nodes after proctectomy and preoperative chemoradiation (C-XRT) may improve survival in good risk patients. The objective of this study was to determine impact of <12 retrieved lymph nodes and lymph node ratio (LNR) on survival in a population with certain poor prognostic features for rectal cancer.
  
  
  METHODS
  Patients who underwent surgery for rectal adenocarcinoma between 2005 and 2011 were divided them into <12 or >12 lymph node groups. The LNR groups were based on interquartile range. Clinicopathological and treatment outcomes were compared. Expected 5 year disease free and overall survival was calculated. Cox proportional hazard model was used to determine independent predictors.
  
  
  RESULTS
  More patients in <12 lymph nodes removed group had low tumors (<5 cm from anal verge) (75.5% versus 60.7%) (P=0.03) and underwent abdominoperineal resection (59.1% versus 42.9%) (P=0.02). Overall survival (OS) and disease free survival (DFS) was not different [(56% and 52% (P=0.7)] [(50% and 57% (P=0.5)]. LNR<0.15 was independent predictor of DFS while LNR ratio<0.12 for OS on multivariate analysis.
  
  
  CONCLUSIONS
  LNR and not number of retrieved nodes impacts survival in younger patients with predominance of anorectal tumors after C-XRT. A specific LNR cutoff remains to be defined.
authors.affiliation: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan. Electronic address: abubakar.hafeez@yahoo.com.
authors.forename: Abu Bakar Hafeez
authors.initials: ABH
authors.lastname: Bhatti
authors.affiliation: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors.forename: Ali
authors.initials: A
authors.lastname: Akbar
authors.affiliation: Sind Medical College, Karachi, Pakistan.
authors.forename: Aqsa
authors.initials: A
authors.lastname: Hafeez
authors.affiliation: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors.forename: Aamir Ali
authors.initials: AA
authors.lastname: Syed
authors.affiliation: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors.forename: Shahid
authors.initials: S
authors.lastname: Khattak
authors.affiliation: Department of Radiation Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors.forename: Arif
authors.initials: A
authors.lastname: Jamshed
authors.affiliation: Department of Medical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors.forename: Ather Saeed
authors.initials: AS
authors.lastname: Kazmi
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000401:mortality / Q000706:statistics & numerical data*; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011351:Proctoscopy; D011379:Prognosis; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D012007:Rectum / Q000601:surgery; D016896:Treatment Outcome
keywords: Chemotherapy; Lymph node; Radiotherapy; Rectal cancer; Survival