Impact of lymph node ratio and number on survival in patients with rectal adenocarcinoma after preoperative chemo radiation

Int J Surg. 2015 Jan:13:65-70. doi: 10.1016/j.ijsu.2014.11.038. Epub 2014 Dec 2.

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.

Conclusion: 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.

Keywords: Chemotherapy; Lymph node; Radiotherapy; Rectal cancer; Survival.

MeSH terms

  • Adenocarcinoma / mortality*
  • Adenocarcinoma / pathology
  • Adenocarcinoma / therapy
  • Adult
  • Aged
  • Chemoradiotherapy
  • Disease-Free Survival
  • Female
  • Humans
  • Lymph Node Excision / mortality
  • Lymph Node Excision / statistics & numerical data*
  • Lymph Nodes / pathology*
  • Lymph Nodes / surgery
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Neoplasm Staging
  • Proctoscopy
  • Prognosis
  • Proportional Hazards Models
  • Rectal Neoplasms / mortality*
  • Rectal Neoplasms / pathology
  • Rectal Neoplasms / therapy
  • Rectum / surgery
  • Treatment Outcome