title: Reduced luminal circumference of tumors plays a key role in anorectal function during the early period after neoadjuvant chemoradiation therapy in rectal cancer patients.
abstract: OBJECTIVE
  The deterioration of anorectal function after neoadjuvant chemoradiation therapy (nCRT) combined with surgery for rectal cancer has not been well defined. The aim of this study was to evaluate the relationship between the tumor response to nCRT and changes in anorectal function during a short-term period after nCRT.
  
  
  METHODS
  We analyzed 100 consecutive patients with available preoperative anorectal manometry data, both before and after nCRT, from 2010 to 2013.
  
  
  RESULTS
  Comparing the manometric data before and after nCRT, the values reflecting rectal sensory function after nCRT was significantly lower than those before nCRT. However, in patients who experienced changed tumor morphology and a reduction in luminal circumferential ratio (LCIR) of tumor after nCRT, the values reflecting rectal sensory function were significantly less decreased after nCRT. On multivariate analysis, the reduction of LCIR after nCRT was a very important factor preventing the impairment of anorectal function during the short-term period in terms of the first rectal sensory threshold (RST) (P = 0.002), the RST of "desire to defecate" (P = 0.006), and rectal compliance (P = 0.003). Additionally, in linear regression analysis, the RST for the desire to defecate was positively affected by tumor morphology (P = 0.015) and the reduced LCIR (P = 0.025), and rectal compliance was positively affected by the reduced LCIR (P = 0.001).
  
  
  CONCLUSIONS
  The nCRT impaired significantly rectal sensory function during the short-term period after nCRT and before a radical operation. However, this reduced LCIR of tumors after nCRT may prevent or minimize impediments to anorectal function during the short-term period after nCRT.
authors.affiliation: Department of Surgery, St. Vincent Hospital, The Catholic University of Korea, 93-6, Ji-dong, Paldal-gu, Suwon-si, Gyeonggi-do, 442-723, Korea.
authors.forename: Bong-Hyeon
authors.initials: BH
authors.lastname: Kye
authors.forename: Hyung-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Hyeon-Min
authors.initials: HM
authors.lastname: Cho
authors.forename: Jun-Gi
authors.initials: JG
authors.lastname: Kim
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Kim
authors.forename: Byoung-Yong
authors.initials: BY
authors.lastname: Shim
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000473:pathology / Q000503:physiopathology*; D059186:Chemoradiotherapy, Adjuvant; D003672:Defecation; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D012004:Rectal Neoplasms / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D012007:Rectum / Q000473:pathology / Q000503:physiopathology*; D012189:Retrospective Studies; D012677:Sensation / Q000502:physiology