title: Clinical examination following preoperative chemoradiation for rectal cancer is not a reliable surrogate end point.
abstract: OBJECTIVE
  Clinical assessment of rectal cancer response to preoperative combined-modality therapy (CMT) using digital rectal examination (DRE) has been proposed as a means of assessing efficacy of therapy. However, because the accuracy of this approach has not been established, we conducted a prospective analysis to determine the operating surgeon's ability to assess response using DRE.
  
  
  METHODS
  Ninety-four prospectively accrued patients with locally advanced rectal cancer (T3/4 or N1) were evaluated with DRE and sigmoidoscopy in order to determine the following tumor characteristics: size, location, mobility, morphology, and circumference. Following preoperative CMT (50.40 Gy with fluorouracil-based chemotherapy) and under general anesthesia, the same surgeon estimated tumor response based on changes in these tumor characteristics, assessed via DRE. Percent pathologic tumor response was determined prospectively by a single pathologist using whole mount sections of the resected cancer.
  
  
  RESULTS
  Clinical assessment using DRE underestimated pathologic response in 73 cases (78%). In addition, DRE was able to identify only 3 of 14 cases (21%) with a pathologic complete response. There were no clinical overestimates of response. None of the clinicopathologic tumor characteristics examined had a significant impact on DRE estimation of response.
  
  
  CONCLUSIONS
  Clinical examination underestimates the extent of rectal cancer response to preoperative CMT. Given the inaccuracy of DRE following preoperative CMT, it should not be used as a sole means of assessing efficacy of therapy nor for selecting patients following CMT for local surgical therapies.
authors.affiliation: Colorectal Service, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, Room C-1077, New York, NY 10021, USA. guillemj@mskcc.org
authors.forename: Jose G
authors.initials: JG
authors.lastname: Guillem
authors.forename: David B
authors.initials: DB
authors.lastname: Chessin
authors.forename: Jinru
authors.initials: J
authors.lastname: Shia
authors.forename: Harvey G
authors.initials: HG
authors.lastname: Moore
authors.forename: Madhu
authors.initials: M
authors.lastname: Mazumdar
authors.forename: Bianca
authors.initials: B
authors.lastname: Bernard
authors.forename: Philip B
authors.initials: PB
authors.lastname: Paty
authors.forename: Leonard
authors.initials: L
authors.lastname: Saltz
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Minsky
authors.forename: Martin R
authors.initials: MR
authors.lastname: Weiser
authors.forename: Larissa K F
authors.initials: LK
authors.lastname: Temple
authors.forename: Alfred M
authors.initials: AM
authors.lastname: Cohen
authors.forename: W Douglas
authors.initials: WD
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D003082:Colectomy / Q000379:methods; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010173:Palpation; D010808:Physical Examination / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011379:Prognosis; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D015996:Survival Rate; D016896:Treatment Outcome