title: Simple criteria to predict margin involvement after chemoradiotherapy and sphincter-sparing for low rectal cancer.
abstract: BACKGROUND
  Low rectal cancers carry a high risk of circumferential margin involvement (CRM+). The anatomy of the lower part of the rectum and a long course of chemoradiotherapy (CRT) limit the accuracy of imaging to predict the CRM+. Additional criteria are required.
  
  
  METHODS
  Eighty six patients undergoing rectal resection with a sphincter-sparing procedure after CRT for low rectal cancer between 2000 and 2013 were retrospectively reviewed. Risk factors of CRM+ and the cut-off number of risk factors required to accurately predict the CRM+ were analyzed.
  
  
  RESULTS
  The CRM+ rate was 9.3% and in the multivariate analysis, the significant risk factors were a tumor size exceeding 3 cm, poor response to CRT and a fixed tumor. The best cut-off to predict CRM+ was the presence of 2 risk factors. Patients with 0-1 and 2-3 risk factors had a CRM+ respectively in 1.3% and 50% of cases and a 3-year recurrence rate of 7% and 35% after a median follow-up of 50 months.
  
  
  CONCLUSIONS
  Poor response, a residual tumor greater than 3 cm and a fixed tumor are predictive of CRM+. Sphincter sparing is an oncological safety procedure for patients with 0-1 criteria but not for patients with 2-3 criteria.
authors.affiliation: Department of Digestive Oncological Surgery, Gustave Roussy Cancer Campus, Villejuif, France. Electronic address: Frederic.DUMONT@gustaveroussy.fr.
authors.forename: F
authors.initials: F
authors.lastname: Dumont
authors.affiliation: Department of Digestive Oncological Surgery, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: C
authors.initials: C
authors.lastname: Tilly
authors.affiliation: Department of Histopathology, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: P
authors.initials: P
authors.lastname: Dartigues
authors.affiliation: Department of Digestive Oncological Surgery, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: D
authors.initials: D
authors.lastname: Goéré
authors.affiliation: Department of Digestive Oncological Surgery, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: C
authors.initials: C
authors.lastname: Honoré
authors.affiliation: Department of Digestive Oncological Surgery, Gustave Roussy Cancer Campus, Villejuif, France.
authors.forename: D
authors.initials: D
authors.lastname: Elias
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000628:therapy; D000328:Adult; D000368:Aged; D001003:Anal Canal; D059248:Chemoradiotherapy; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D059351:Organ Sparing Treatments; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy; D012007:Rectum / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Chemoradiotherapy; Circumferential margin; Low rectum; Poor response; Rectal cancer; Sphincter sparing