title: Radiotherapy does not compensate for positive resection margins in rectal cancer patients: report of a multicenter randomized trial.
abstract: OBJECTIVE
  Circumferential resection margin (CRM) involvement is a prognostic factor for local recurrence in rectal cancer. In a randomized trial comparing preoperative radiotherapy (5 x 5 Gy), followed by total mesorectal excision (TME) with TME alone, we demonstrated the beneficial effect of short-term preoperative radiotherapy on local recurrences. Here we evaluate the effect of radiotherapy on local recurrence rates in patients with different CRM involvements.
  
  
  METHODS
  Circumferential margins were defined as positive (< or =1 mm), narrow (1.1-2 mm), or wide (>2 mm). Postoperative radiotherapy was mandatory for surgery-only patients with a positive CRM, but was not always administered and enabled us to compare local recurrence rates for patients with or without postoperative radiotherapy. Furthermore, the effect of preoperative radiotherapy was assessed in the different margin groups.
  
  
  RESULTS
  Of 120 patients in the surgery-only group with a positive CRM, 47% received postoperative radiotherapy. There was no difference in the local recurrence rate between the irradiated and nonirradiated patients (17.3% vs. 15.7%, p = 0.98). Preoperative radiotherapy was effective in patients with a narrow CRM (0% vs. 14.9%, p = 0.02) or wide CRM (0.9 vs. 5.8%, p < 0.0001), but not in patients with positive margins (9.3% vs. 16.4%, p = 0.08).
  
  
  CONCLUSIONS
  Preoperative hypofractionated radiotherapy has a beneficial effect in patients with wide or narrow resection margins, but cannot compensate for microscopically irradical resections resulting in positive margins.
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands. marijnen@lumc.nl
authors.forename: C A M
authors.initials: CA
authors.lastname: Marijnen
authors.forename: I D
authors.initials: ID
authors.lastname: Nagtegaal
authors.forename: E
authors.initials: E
authors.lastname: Kapiteijn
authors.forename: E Klein
authors.initials: EK
authors.lastname: Kranenbarg
authors.forename: E M
authors.initials: EM
authors.lastname: Noordijk
authors.forename: J H J M
authors.initials: JH
authors.lastname: van Krieken
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: J W H
authors.initials: JW
authors.lastname: Leer
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000473:pathology / Q000601:surgery; D001706:Biopsy; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000517:prevention & control*; D018365:Neoplasm, Residual; D009426:Netherlands / Q000453:epidemiology; D010502:Perineum / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D012007:Rectum / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome