title: Predictors of Pathologic Complete Response After Neoadjuvant Treatment for Rectal Cancer: A Multicenter Study.
abstract: BACKGROUND
  Pathologic complete response (pCR) to neoadjuvant chemoradiation (CRT) for rectal cancer is associated with better long-term outcomes, and is used as an early indicator of response to novel agents. To assess the rate and predictors of pCR, we performed a retrospective multicenter study involving 5 Canadian cancer centers.
  
  
  METHODS
  Cancer registries identified consecutive patients with locally advanced rectal adenocarcinoma from the Tom Baker Cancer Centre, Cross Cancer Institute, British Columbia Cancer Agency, Ottawa Hospital Cancer Centre, and the Dr H. Bliss Murphy Cancer Centre who received fluoropyrimidine-based CRT and had curative intent surgery from 2005 to 2012. Patient, tumor, and therapy characteristics were correlated with response.
  
  
  RESULTS
  Of the 891 patients included, 885 patients had pCR data available. Of the included patients, 161 (18.2%) had a pCR to CRT, and 724 (81.8%) did not. Patients with a pCR had a lower pretreatment carcinoembryonic antigen (CEA) level, and higher hemoglobin level in univariate analysis. In multivariable analysis, statin use at baseline (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.02-2.92; P = .04), lower pretreatment CEA level (OR, 1.03; 95% CI, 1.01-1.06; P = .03), and distance closer to anal verge (OR, 1.07; 95% CI, 1.01-1.15; P = .04) were significant predictors of pCR. The 3-year disease-free survival was 86% in those with a pCR versus 62.5% in those without a pCR (P < .0001) and pCR was associated with improved overall survival (hazard ratio, 0.29; 95% CI, 0.17-0.51; P < .0001).
  
  
  CONCLUSIONS
  Lower pretreatment CEA level, proximity to anal verge, and statin use are predictors of pCR in our large retrospective cohort. Clinical trials to investigate statins combined with neoadjuvant CRT might be warranted.
authors.affiliation: Cross Cancer Institute, Edmonton, Alberta, Canada. Electronic address: dawn.armstrong@easternhealth.ca.
authors.forename: Dawn
authors.initials: D
authors.lastname: Armstrong
authors.affiliation: Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Soundouss
authors.initials: S
authors.lastname: Raissouni
authors.affiliation: Cross Cancer Institute, Edmonton, Alberta, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Price Hiller
authors.affiliation: Dr H. Bliss Murphy Cancer Centre, St John's, Newfoundland, Canada.
authors.forename: Jamison
authors.initials: J
authors.lastname: Mercer
authors.affiliation: Dr H. Bliss Murphy Cancer Centre, St John's, Newfoundland, Canada.
authors.forename: Erin
authors.initials: E
authors.lastname: Powell
authors.affiliation: University of Calgary, Calgary, Alberta, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: MacLean
authors.affiliation: University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Maria
authors.initials: M
authors.lastname: Jiang
authors.affiliation: Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Corinne
authors.initials: C
authors.lastname: Doll
authors.affiliation: The Ottawa Hospital Cancer Centre, Ottawa, Ontario, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: Goodwin
authors.affiliation: Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Eugene
authors.initials: E
authors.lastname: Batuyong
authors.affiliation: British Columbia Cancer Agency, Vancouver, British Columbia, Canada.
authors.forename: Kevin
authors.initials: K
authors.lastname: Zhou
authors.affiliation: Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Jose G
authors.initials: JG
authors.lastname: Monzon
authors.affiliation: Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Tang
authors.affiliation: Tom Baker Cancer Centre, Calgary, Alberta, Canada.
authors.forename: Daniel Y
authors.initials: DY
authors.lastname: Heng
authors.affiliation: British Columbia Cancer Agency, Vancouver, British Columbia, Canada.
authors.forename: Winson Y
authors.initials: WY
authors.lastname: Cheung
authors.affiliation: The Ottawa Hospital Cancer Centre, Ottawa, Ontario, Canada.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Vickers
mesh_terms: D002170:Canada; D002272:Carcinoembryonic Antigen / Q000097:blood*; D059248:Chemoradiotherapy / Q000379:methods*; D018572:Disease-Free Survival; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D002272:Carcinoembryonic Antigen; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors
keywords: Carcinoembryonic antigen level; Neoadjuvant chemoradiation; Pathologic response; Predictive factors; Statin