title: Rectal cancer: mucinous carcinoma on magnetic resonance imaging indicates poor response to neoadjuvant chemoradiation.
abstract: OBJECTIVE
  To assess response of locally advanced rectal carcinoma to chemoradiation with regard to mucinous status and local tumor invasion found at pretherapeutic magnetic resonance imaging (MRI).
  
  
  METHODS
  A total of 88 patients were included in this prospective study of patients with advanced mrT3 and mrT4 carcinomas. Carcinomas were categorized by MRI as mucinous (mucin proportion >50% within the tumor volume), and as nonmucinous. Patients received neoadjuvant chemoradiation consisting of 50.4 Gy (1.8 Gy/fraction) and 5-fluorouracil on Days 1 to 5 and Days 29 to 33. Therapy response was assessed by comparing pretherapeutic MRI with histopathology of surgical specimens (minimum distance between outer tumor edge and circumferential resection margin = CRM, T, and N category).
  
  
  RESULTS
  A mucinous carcinoma was found in 21 of 88 patients. Pretherapeutic mrCRM was 0 mm (median) in the mucinous and nonmucinous group. Of the 88 patients, 83 underwent surgery with tumor resection. The ypCRM (mm) at histopathology was significantly lower in mucinous carcinomas than in nonmucinous carcinomas (p ≤ 0.001). Positive resection margins (ypCRM ≤ 1 mm) were found more frequently in mucinous carcinomas than in nonmucinous ones (p ≤ 0.001). Treatment had less effect on local tumor stage in mucinous carcinomas than in nonmucinous carcinomas (for T downsizing, p = 0.012; for N downstaging, p = 0.007). Disease progression was observed only in patients with mucinous carcinomas (n = 5).
  
  
  CONCLUSIONS
  Mucinous status at pretherapeutic MRI was associated with a noticeably worse response to chemoradiation and should be assessed by MRI in addition to local tumor staging to estimate response to treatment before it is initiated.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University Mainz, Mainz, Germany. oberholz@radiologie.klinik.uni-mainz.de
authors.forename: Katja
authors.initials: K
authors.lastname: Oberholzer
authors.forename: Matthias
authors.initials: M
authors.lastname: Menig
authors.forename: Andreas
authors.initials: A
authors.lastname: Kreft
authors.forename: Astrid
authors.initials: A
authors.lastname: Schneider
authors.forename: Theodor
authors.initials: T
authors.lastname: Junginger
authors.forename: Achim
authors.initials: A
authors.lastname: Heintz
authors.forename: Karl-Friedrich
authors.initials: KF
authors.lastname: Kreitner
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Hötker
authors.forename: Torsten
authors.initials: T
authors.lastname: Hansen
authors.forename: Christoph
authors.initials: C
authors.lastname: Düber
authors.forename: Heinz
authors.initials: H
authors.lastname: Schmidberger
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D002277:Carcinoma / Q000473:pathology / Q000628:therapy; D059248:Chemoradiotherapy / Q000379:methods*; D019583:Dose Fractionation, Radiation; D004334:Drug Administration Schedule; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil