title: MR imaging of rectal cancer before and after chemoradiation therapy.
abstract: OBJECTIVE
  This study was done to determine the diagnostic accuracy of magnetic resonance (MR) imaging in patients with rectal carcinoma by comparing post-chemoradiation MR imaging with pathological specimens.
  
  
  METHODS
  We enrolled 39 patients with locally advanced rectal cancer. All patients received chemoradiation therapy before surgery and neoadjuvant chemoradiation therapy followed by MR imaging. MR images were analysed by a team of two expert radiologists unaware of the clinical and histopathological findings.
  
  
  RESULTS
  Following neoadjuvant chemoradiation therapy, the analysis of MR images showed 23 (59%) patients with a rectal disease staged ≤T2 and 16 (41%) with a disease staged >T2. Post-treatment histological staging (TNM) revealed 13 patients with a disease >T2 and 26 patients with a disease ≤T2. Cohen's kappa to measure concordance between post-chemoradiation MR staging and histological response showed 83.6% concordance for disease confined to the serosa (≤T3): concordance was 97.22% for disease ≤N1 and 33.33% for disease >N1.
  
  
  CONCLUSIONS
  MR imaging is critical for discovering T3 disease; moreover, morphological MR imaging does not always provide the opportunity to discern small residual cancer cells hidden in fibrotic tissue that could cause involvement of circumferential resection margin (CRM) on histology.
authors.affiliation: Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, Trigoria, Rome, Italy. r.delvescovo@unicampus.it
authors.forename: R
authors.initials: R
authors.lastname: Del Vescovo
authors.forename: L E
authors.initials: LE
authors.lastname: Trodella
authors.forename: I
authors.initials: I
authors.lastname: Sansoni
authors.forename: R L
authors.initials: RL
authors.lastname: Cazzato
authors.forename: S
authors.initials: S
authors.lastname: Battisti
authors.forename: F
authors.initials: F
authors.lastname: Giurazza
authors.forename: S
authors.initials: S
authors.lastname: Ramella
authors.forename: F
authors.initials: F
authors.lastname: Cellini
authors.forename: R F
authors.initials: RF
authors.lastname: Grasso
authors.forename: L
authors.initials: L
authors.lastname: Trodella
authors.forename: B
authors.initials: B
authors.lastname: Beomonte Zobel
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D000069287:Capecitabine; D059248:Chemoradiotherapy; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000031:analogs & derivatives; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D003841:Deoxycytidine; D000069287:Capecitabine; D005472:Fluorouracil