title: Complementary value of pre-treatment apparent diffusion coefficient in rectal cancer for predicting tumor recurrence.
abstract: To assess the complementary prognostic value of pre-treatment tumor apparent diffusion coefficient (ADC) for the prediction of tumor recurrence in patients with rectal cancer.
  
  
  
  From March 2012 to March 2013, a total of 128 patients with mid/lower rectal cancer who underwent pre-treatment rectal MRI were enrolled in this retrospective study. Two radiologists in consensus evaluated conventional imaging features (Cimg) in pre-treatment rectal MRI: tumor height from anal verge (≤5 cm vs. >5 cm), T stage (high vs. low), the presence or absence of lymph node metastasis, mesorectal fascia invasion, and extramural venous invasion. The mean tumor ADC values (TumorADC) based on high b-value (0, 1000 × 10(-3) mm(2)/s) diffusion weight images were extracted. A multivariate Cox proportional hazard (CPH) regression was performed to evaluate the association of Cimg and TumorADC with the 3-year local recurrence (LR) rate. Predictive performance of two multivariate CPH models (Cimg only vs. Cimg + TumorADC) was compared using Harrell's c index (HCI).
  
  
  
  TumorADC (Adjusted HR, 7.830; 95% CI 3.937-15.571) and high T stage (Adjusted HR, 8.039; 95% CI 2.405-26.874) were independently associated with the 3-year LR rate. The CPH model generated with T stage + TumorADC (HCI, 0.820; 95% CI 0.708-0.932) showed significantly higher HCI than that with T stage only (HCI, 0.742; 95% CI 0.594-0.889) (P = 0.009).
  
  
  
  In patients with mid/lower rectal cancer, integrating TumorADC to Cimg increases predictive performance of the CPH model than that with Cimg alone for the prediction of LR within 3 years after surgery.
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Sung Jun
authors.initials: SJ
authors.lastname: Moon
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea. shcho2405@gmail.com.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Cho
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Gab Chul
authors.initials: GC
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Won Hwa
authors.initials: WH
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Kyung-Min
authors.initials: KM
authors.lastname: Shin
authors.affiliation: Department of Radiology, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: So Mi
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Colorectal Cancer Center, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Jun Seok
authors.initials: JS
authors.lastname: Park
authors.affiliation: Colorectal Cancer Center, Kyungpook National University Medical Center, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu, 702-210, Republic of Korea.
authors.forename: Gyu-Seog
authors.initials: GS
authors.lastname: Choi
authors.affiliation: Department of Radiology, Dongsan Hospital, College of Medicine, Keimyung University, 56 Dalseong-ro, Jung-gu, Daegu, 700-712, Republic of Korea.
authors.forename: See Hyung
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies
keywords: Apparent diffusion coefficient (ADC); Diffusion-weighted image (DWI); Magnetic resonance imaging (MRI); Prognosis; Rectal cancer