title: Circumferential margin involvement is the crucial prognostic factor after multimodality treatment in patients with locally advanced rectal carcinoma.
abstract: OBJECTIVE
  After preoperative (radio)chemotherapy, histologic determinants for prognostication have changed. It is unclear which variables, including assessment of tumor regression, are the best indicators for local recurrence and survival.
  
  
  METHODS
  A series of 201 patients with locally advanced rectal cancer (cT3/T4, M0) presenting with an involved or at least threatened circumferential margin (CRM) on preoperative imaging (<2 mm) were evaluated using standard histopathologic variables and four different histologic regression systems. All patients received neoadjuvant radiochemotherapy or radiotherapy. The prognostic value of all factors was tested with univariate survival analysis of time to local recurrence and overall survival.
  
  
  RESULTS
  Local recurrence occurred in only 8% of the patients with a free CRM compared with 43% in case of CRM involvement (P < 0.0001). None of the four regression systems were associated with prognosis, not even when corrected for CRM status. However, we did observe a higher degree of tumor regression after radiochemotherapy compared with radiotherapy (P < 0.001). Absence of tumor regression was associated with increasing invasion depth and a positive CRM (P = 0.02 and 0.03, respectively).
  
  
  CONCLUSIONS
  Assessment of CRM involvement is the most important pathologic variable after radiochemotherapy. Although tumor regression increases the chance on a free CRM, in cases with positive resection margins prognosis is poor irrespective of the degree of therapy-induced regression.
authors.affiliation: Departments of Surgery and Radiotherapy, Catharina Hospital, Medical Centre Rijnmond-South, Rotterdam, the Netherlands.
authors.forename: Marleen J E M
authors.initials: MJ
authors.lastname: Gosens
authors.forename: René A
authors.initials: RA
authors.lastname: Klaassen
authors.forename: Ivonne
authors.initials: I
authors.lastname: Tan-Go
authors.forename: Harm J T
authors.initials: HJ
authors.lastname: Rutten
authors.forename: Hendrik
authors.initials: H
authors.lastname: Martijn
authors.forename: Adriaan J C
authors.initials: AJ
authors.lastname: van den Brule
authors.forename: Grard A P
authors.initials: GA
authors.lastname: Nieuwenhuijzen
authors.forename: J Han J M
authors.initials: JH
authors.lastname: van Krieken
authors.forename: Iris D
authors.initials: ID
authors.lastname: Nagtegaal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000473:pathology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*