title: Oncologic relevance of magnetic resonance imaging-detected threatened mesorectal fascia for patients with mid or low rectal cancer: A longitudinal analysis before and after long-course, concurrent chemoradiotherapy.
abstract: The oncologic importance of threatened mesorectal fascia detected with magnetic resonance imaging is obscured by the heterogeneity of preoperative treatments. We evaluated the oncologic relevance of threatened mesorectal fascia detected with consecutive magnetic resonance imaging performed before and after long-course, concurrent chemoradiotherapy (LCRT) for mid or low rectal cancer.
  
  
  
  We evaluated 196 patients who underwent total mesorectal excision with LCRT. Threatened mesorectal fascia was defined as a shortest distance from tumor to mesorectal fascia of ≤ 1 mm on magnetic resonance imaging. Multivariate analyses for disease-free survival using magnetic resonance imaging-based parameters were conducted with a Cox proportional hazard model before and after LCRT, respectively.
  
  
  
  The pathologic positivity of the circumferential resection margin was greater for threatened mesorectal fascia than for clear mesorectal fascia (pre-LCRT, 14.8% vs 3.0%, P = .004; post-LCRT, 15.4% vs 4.5%, P = .025). At a median follow-up of 68 months, 3-year disease-free survival was worse for threatened mesorectal fascia than for clear mesorectal fascia (pre-LCRT, 77.0% vs 88.1%, P = .023; post-LCRT, 76.9% vs 86.6%, P = .029). On multivariate analyses, threatened mesorectal fascia on pre-LCRT magnetic resonance imaging was an independent factor for poor disease-free survival (hazard ratio = 2.153, 95% confidence interval, 1.07-4.32, P = .031), whereas threatened mesorectal fascia on post-LCRT magnetic resonance imaging was not (hazard ratio = 1.689, 95% confidence interval, 0.77-3.66, P = .189).
  
  
  
  This study confirms that magnetic resonance imaging-detected threatened mesorectal fascia predicts poor oncologic outcomes for mid or low rectal cancer and shows that the diagnostic performance of pre-LCRT magnetic resonance imaging is different from that of post-LCRT magnetic resonance imaging.
authors.affiliation: Department of Surgery, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Il Tae
authors.initials: IT
authors.lastname: Son
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Kyoung Ho
authors.initials: KH
authors.lastname: Lee
authors.affiliation: Department of Surgery, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Sung Il
authors.initials: SI
authors.lastname: Kang
authors.affiliation: Department of Surgery, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Duck-Woo
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Eun
authors.initials: E
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Keun-Wook
authors.initials: KW
authors.lastname: Lee
authors.affiliation: Division of Statistics, Medical Research Collaborating Center, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Soyeon
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul National University Bundang Hospital, Seongnam, South Korea. Electronic address: kangsb@snubh.org.
authors.forename: Sung-Bum
authors.initials: SB
authors.lastname: Kang
mesh_terms: D000368:Aged; D059248:Chemoradiotherapy; D018572:Disease-Free Survival; D005205:Fascia / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome