title: Prognostic significance of a preoperative magnetic resonance imaging assessment of the distance of mesorectal extension in clinical T3 lower rectal cancer.
abstract: OBJECTIVE
  The aim of this study was to evaluate the association between the mesorectal extensions on high-resolution magnetic resonance imaging (MRI) and the prognosis of patients with clinical T3 lower rectal cancer.
  
  
  METHODS
  Fifty-eight patients with clinical T3 lower rectal cancer were investigated using high-resolution MRI. One radiologist who was blinded to the clinicopathological findings retrospectively examined the MRI-predicted circumferential resection margin (mrCRM) and the distance of mesorectal extension (mrDME) on the scans. If the imaging showed a tumor ≤1 mm from the mesorectal fascia, then the mrCRM involvement was defined as potentially present. The tumors were divided into two groups: mrDME ≤4 mm and mrDME >4 mm.
  
  
  RESULTS
  A survival analysis showed that mrCRM-positive patients had a significantly poorer prognosis in the RFS (p < 0.01) and LRFS (p < 0.01). Patients with mrDME >4 mm revealed a significantly poorer prognosis than those with mrDME ≤4 mm in the OS (p = 0.04), RFS (p < 0.01), and LRFS (p = 0.04). A multivariate analysis revealed that both mrCRM and mrDME on MRI had a significant impact on the RFS (p = 0.01 and 0.03, respectively).
  
  
  CONCLUSIONS
  The mrDME, as well as the mrCRM, may be an important preoperative prognostic factor for patients with clinical T3 lower rectal cancer.
authors.affiliation: Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3, Nakamichi, Higashinari-ku, Osaka, 537-8511, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sueda
authors.affiliation: Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3, Nakamichi, Higashinari-ku, Osaka, 537-8511, Japan. ohue-ma@mc.pref.osaka.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohue
authors.affiliation: Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3, Nakamichi, Higashinari-ku, Osaka, 537-8511, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Noura
authors.affiliation: Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3, Nakamichi, Higashinari-ku, Osaka, 537-8511, Japan.
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Shingai
authors.affiliation: Department of Radiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3, Nakamichi, Higashinari-ku, Osaka, 537-8511, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Nakanishi
authors.affiliation: Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3, Nakamichi, Higashinari-ku, Osaka, 537-8511, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Yano
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D057234:Preoperative Period; D011379:Prognosis; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D012007:Rectum / Q000000981:diagnostic imaging* / Q000473:pathology*
keywords: Circumferential resection margin; Distance of mesorectal extension; Lower rectal cancer; Magnetic resonance imaging