title: Magnetic resonance imaging-detected tumor response for locally advanced rectal cancer predicts survival outcomes: MERCURY experience.
abstract: OBJECTIVE
  To assess magnetic resonance imaging (MRI) and pathologic staging after neoadjuvant therapy for rectal cancer in a prospectively enrolled, multicenter study.
  
  
  METHODS
  In a prospective cohort study, 111 patients who had rectal cancer treated by neoadjuvant therapy were assessed for response by MRI and pathology staging by T, N and circumferential resection margin (CRM) status. Tumor regression grade (TRG) was also assessed by MRI. Overall survival (OS) was estimated by using the Kaplan-Meier product-limit method, and Cox proportional hazards models were used to determine associations between staging of good and poor responders on MRI or pathology and survival outcomes after controlling for patient characteristics.
  
  
  RESULTS
  On multivariate analysis, the MRI-assessed TRG (mrTRG) hazard ratios (HRs) were independently significant for survival (HR, 4.40; 95% CI, 1.65 to 11.7) and disease-free survival (DFS; HR, 3.28; 95% CI, 1.22 to 8.80). Five-year survival for poor mrTRG was 27% versus 72% (P = .001), and DFS for poor mrTRG was 31% versus 64% (P = .007). Preoperative MRI-predicted CRM independently predicted local recurrence (LR; HR, 4.25; 95% CI, 1.45 to 12.51). Five-year survival for poor post-treatment pathologic T stage (ypT) was 39% versus 76% (P = .001); DFS for the same was 38% versus 84% (P = .001); and LR for the same was 27% versus 6% (P = .018). The 5-year survival for involved pCRM was 30% versus 59% (P = .001); DFS, 28 versus 62% (P = .02); and LR, 56% versus 10% (P = .001). Pathology node status did not predict outcomes.
  
  
  CONCLUSIONS
  MRI assessment of TRG and CRM are imaging markers that predict survival outcomes for good and poor responders and provide an opportunity for the multidisciplinary team to offer additional treatment options before planning definitive surgery. Postoperative histopathology assessment of ypT and CRM but not post-treatment N status were important postsurgical predictors of outcome.
authors.affiliation: The Royal Marsden Hospital NHS Trust, Sutton, United Kingdom, SM2 5PT.
authors.forename: Uday B
authors.initials: UB
authors.lastname: Patel
authors.forename: Fiona
authors.initials: F
authors.lastname: Taylor
authors.forename: Lennart
authors.initials: L
authors.lastname: Blomqvist
authors.forename: Christopher
authors.initials: C
authors.lastname: George
authors.forename: Hywel
authors.initials: H
authors.lastname: Evans
authors.forename: Paris
authors.initials: P
authors.lastname: Tekkis
authors.forename: Philip
authors.initials: P
authors.lastname: Quirke
authors.forename: David
authors.initials: D
authors.lastname: Sebag-Montefiore
authors.forename: Brendan
authors.initials: B
authors.lastname: Moran
authors.forename: Richard
authors.initials: R
authors.lastname: Heald
authors.forename: Ashley
authors.initials: A
authors.lastname: Guthrie
authors.forename: Nicola
authors.initials: N
authors.lastname: Bees
authors.forename: Ian
authors.initials: I
authors.lastname: Swift
authors.forename: Kjell
authors.initials: K
authors.lastname: Pennert
authors.forename: Gina
authors.initials: G
authors.lastname: Brown
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D015996:Survival Rate