title: Comparison between preoperative and postoperative concurrent chemoradiotherapy for rectal cancer: an institutional analysis.
abstract: OBJECTIVE
  To evaluate the treatment outcomes of preoperative versus postoperative concurrent chemoradiotherapy (CRT) on locally advanced rectal cancer.
  
  
  METHODS
  Medical data of 114 patients with locally advanced rectal cancer treated with CRT preoperatively (54 patients) or postoperatively (60 patients) from June 2003 to April 2011 was analyzed retrospectively. 5-Fluorouracil (5-FU) or a precursor of 5-FU-based concurrent CRT (median, 50.4 Gy) and total mesorectal excision were conducted for all patients. The median follow-up duration was 43 months (range, 16 to 118 months). The primary end point was disease-free survival (DFS). The secondary end points were overall survival (OS), locoregional control, toxicity, and sphincter preservation rate.
  
  
  RESULTS
  The 5-year DFS rate was 72.1% and 48.6% for the preoperative and postoperative CRT group, respectively (p = 0.05, the univariate analysis; p = 0.10, the multivariate analysis). The 5-year OS rate was not significantly different between the groups (76.2% vs. 69.0%, p = 0.23). The 5-year locoregional control rate was 85.2% and 84.7% for the preoperative and postoperative CRT groups (p = 0.98). The sphincter preservation rate of low-lying tumor showed significant difference between both groups (58.1% vs. 25.0%, p = 0.02). Pathologic tumor and nodal down-classification occurred after the preoperative CRT (53.7% and 77.8%, both p < 0.001). Acute and chronic toxicities were not significantly different between both groups (p = 0.10 and p = 0.62, respectively).
  
  
  CONCLUSIONS
  The results confirm that preoperative CRT can be advantageous for improving down-classification rate and the sphincter preservation rate of low-lying tumor in rectal cancer.
authors.affiliation: Department of Radiation Oncology, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Jeong Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Jun-Gi
authors.initials: JG
authors.lastname: Kim
authors.forename: Seong Taek
authors.initials: ST
authors.lastname: Oh
authors.forename: Hyuk Jun
authors.initials: HJ
authors.lastname: Chung
authors.forename: Myung Ah
authors.initials: MA
authors.lastname: Lee
authors.forename: Hoo Geun
authors.initials: HG
authors.lastname: Chun
authors.forename: Song Mi
authors.initials: SM
authors.lastname: Jeong
authors.forename: Sei Chul
authors.initials: SC
authors.lastname: Yoon
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Jang
keywords: Concurrent chemoradiotherapy; Rectal cancer