title: Clinical criteria underestimate complete pathological response in rectal cancer treated with neoadjuvant chemoradiotherapy.
abstract: BACKGROUND
  Published criteria define specific mucosal features of clinical complete response for rectal cancer after neoadjuvant chemoradiotherapy.
  
  
  OBJECTIVE
  The aim of this study was to determine the performance of these criteria to identify a pathological complete response.
  
  
  METHODS
  Histopathology reports were retrieved for consecutive rectal cancers treated with neoadjuvant therapy followed by proctectomy. The mucosal appearance of residual disease was compared with the final pathological stage.
  
  
  METHODS
  This study was conducted at a single-institution, tertiary referral center.
  
  
  METHODS
  The study included 238 patients.
  
  
  METHODS
  All patients underwent neoadjuvant chemoradiation followed by proctectomy between 1997 and 2007.
  
  
  METHODS
  Gross mucosal appearance was compared with the final pathological stage.
  
  
  RESULTS
  Following neoadjuvant chemoradiation, 61 of 238 (25%) patients were downstaged to ypT0. Forty-five of these 61 patients (74%) had a residual mucosal abnormality that precluded assignment of a complete response. Of these, 40 had residual ulcers (up to 10 mm in depth) and 5 had exophytic lesions. The remaining 16 patients with pathological complete response fulfilled criteria for clinical complete response and had either no visible abnormality or a scar. Although mucosal complete clinical response was statistically associated with ypT0 status (p < 0.0001), 6 of 22 (27%) patients with mucosal complete clinical response still had residual disease. Smaller size of residual mucosal abnormality was also associated with ypT0 status (p = 0.002).
  
  
  CONCLUSIONS
  This is a retrospective study and preoperative clinical assessment of response is not recorded for comparison to resected specimens.
  
  
  CONCLUSIONS
  The majority of patients attaining ypT0 status do not display mucosal features of complete response. When present, a mucosal complete response is statistically associated with ypT0 status, but is poorly sensitive. If rectal conservation after chemoradiation is to be pursued, alternative means of restaging are required to maximize the number who might benefit from this approach.
authors: 1Department of Colorectal Surgery, Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio 2Department of Pathology, Cleveland Clinic, Cleveland, Ohio 3Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.
authors: Fraser M
authors: FM
authors: Smith
authors: Homer
authors: H
authors: Wiland
authors: Adam
authors: A
authors: Mace
authors: Rish K
authors: RK
authors: Pai
authors: Matthew F
authors: MF
authors: Kalady
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D003131:Combined Modality Therapy; D003952:Diagnostic Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome