title: What is the significance of the circumferential margin in locally advanced rectal cancer after neoadjuvant chemoradiotherapy?
abstract: BACKGROUND
  The circumferential resection margin (CRM) is highly prognostic for local recurrence in rectal cancer surgery without neoadjuvant treatment. However, its significance in the setting of long-course neoadjuvant chemoradiotherapy (nCRT) is not well defined.
  
  
  METHODS
  Review of a single institution's prospectively maintained database from 1998 to 2007 identified 563 patients with locally advanced rectal cancer (T3/T4 and/or N1) receiving nCRT, followed after 6 weeks by total mesorectal excision (TME). Kaplan-Meier, Cox regression, and competing risk analysis were performed.
  
  
  RESULTS
  The authors noted that 75 % of all patients had stage III disease as determined by endorectal ultrasound (ERUS) and/or magnetic resonance imaging (MRI). With median follow-up of 39 months after resection, local and distant relapse were noted in 12 (2.1 %) and 98 (17.4 %) patients, respectively. On competing risk analysis, the optimal cutoff point of CRM was 1 mm for local recurrence and 2 mm for distant metastasis. Factors independently associated with local recurrence included CRM ≤1 mm, and high-grade tumor (p = 0.012 and 0.007, respectively). CRM ≤2 mm, as well as pathological, nodal, and overall tumor stage are also significant independent risk factors for distant metastasis (p = 0.025, 0.010, and <0.001, respectively).
  
  
  CONCLUSIONS
  In this dataset of locally advanced rectal cancer treated with nCRT followed by TME, CRM ≤1 mm is an independent risk factor for local recurrence and is considered a positive margin. CRM ≤2 mm was associated with distant recurrence, independent of pathological tumor and nodal stage.
authors: Colorectal Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors: Atthaphorn
authors: A
authors: Trakarnsanga
authors: Mithat
authors: M
authors: Gonen
authors: Jinru
authors: J
authors: Shia
authors: Karyn A
authors: KA
authors: Goodman
authors: Garrett M
authors: GM
authors: Nash
authors: Larissa K
authors: LK
authors: Temple
authors: José G
authors: JG
authors: Guillem
authors: Philip B
authors: PB
authors: Paty
authors: Julio
authors: J
authors: Garcia-Aguilar
authors: Martin R
authors: MR
authors: Weiser
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D000293:Adolescent; D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000401:mortality; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D012307:Risk Factors; D015996:Survival Rate; D055815:Young Adult