title: Preoperative chemoradiotherapy effects on anastomotic leakage after rectal cancer resection: a propensity score matching analysis.
abstract: OBJECTIVE
  To assess the effects of preoperative chemoradiotherapy (CRT) on anastomotic leakage (AL) after rectal cancer resection, using propensity score matching.
  
  
  BACKGROUND
  Conflicting data have emerged over the last decade regarding the effect of preoperative CRT on AL.
  
  
  METHODS
  We reviewed 1437 consecutive patients with rectal cancer who underwent low anterior resection (LAR) at our institution between 2005 and 2012. AL evaluated as grade C was the primary endpoint, as proposed by the International Study Group of Rectal Cancer in 2010. The patients were treated with (n = 360) or without (n = 1077) preoperative CRT. The total radiation dose was 50.4 Gy in 28 fractions. Multivariate and propensity score matching analyses were used to compensate for the differences in some baseline characteristics.
  
  
  RESULTS
  The preoperative CRT group contained more patients with the following characteristics, older age, male sex, smoker, advanced stage tumor, lower/mid rectal tumor location, ultra-LAR, and diverting stoma, than the non-preoperative CRT group (all Ps < 0.05). Postoperative AL occurred in 91 patients (6.3%). Before propensity score matching, the incidence of AL in patients with or without preoperative CRT was 7.5% and 5.9%, respectively (P = 0.293). After propensity score matching, the 2 groups were nearly balanced except for the initial stage and the length of the surgeon's career, and the incidence of AL in patients with or without preoperative CRT was 7.5% and 8.1%, respectively (P = 0.781).
  
  
  CONCLUSIONS
  We did not observe that preoperative CRT increased the risk of postoperative AL after LAR in patients with rectal cancer, using propensity score matching analysis.
authors.affiliation: Departments of *Radiation Oncology; and †Surgery, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jee Suk
authors.initials: JS
authors.lastname: Chang
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Keum
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
authors.forename: Seung Hyuk
authors.initials: SH
authors.lastname: Baik
authors.forename: Byung So
authors.initials: BS
authors.lastname: Min
authors.forename: Hyuk
authors.initials: H
authors.lastname: Huh
authors.forename: Chang Geol
authors.initials: CG
authors.lastname: Lee
authors.forename: Woong Sub
authors.initials: WS
authors.lastname: Koom
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods; D057868:Anastomotic Leak / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D059248:Chemoradiotherapy; D003113:Colonoscopy; D013505:Digestive System Surgical Procedures / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D011379:Prognosis; D057216:Propensity Score; D012004:Rectal Neoplasms / Q000628:therapy*; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed