title: Extended Intervals after Neoadjuvant Therapy in Locally Advanced Rectal Cancer: The Key to Improved Tumor Response and Potential Organ Preservation.
abstract: BACKGROUND
  Many rectal cancer patients experience tumor downstaging and some are found to achieve a pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT). Previous data suggest that there is an association between the time interval from nCRT completion to surgery and tumor response rates, including pCR. However, these studies have been primarily from single institutions with small sample sizes. The aim of this study was to examine the relationship between a longer interval after nCRT and pCR in a nationally representative cohort of rectal cancer patients.
  
  
  METHODS
  Clinical stage II to III rectal cancer patients undergoing nCRT with a documented surgical resection were selected from the 2006 to 2011 National Cancer Data Base. Multivariable logistic regression analysis was used to assess the association between the nCRT-surgery interval time (<6 weeks, 6 to 8 weeks, >8 weeks) and the odds of pCR. The relationship between nCRT-surgery interval, surgical morbidity, and tumor downstaging was also examined.
  
  
  RESULTS
  Overall, 17,255 patients met the inclusion criteria. An nCRT-surgery interval time >8 weeks was associated with higher odds of pCR (odds ratio [OR] 1.12, 95% CI 1.01 to 1.25) and tumor downstaging (OR 1.11, 95% CI 1.02 to 1.25). The longer time delay was also associated with lower odds of 30-day readmission (OR 0.82, 95% CI 0.70 to 0.92).
  
  
  CONCLUSIONS
  An nCRT-surgery interval time >8 weeks results in increased odds of pCR, with no evidence of associated increased surgical complications compared with an interval of 6 to 8 weeks. These data support implementation of a lengthened interval after nCRT to optimize the chances of pCR and perhaps add to the possibility of ultimate organ preservation (nonoperative management).
authors.affiliation: Surgical Health Outcomes & Research Enterprise (SHORE), University of Rochester Medical Center, Rochester, NY.
authors.forename: Christian P
authors.initials: CP
authors.lastname: Probst
authors.affiliation: Surgical Health Outcomes & Research Enterprise (SHORE), University of Rochester Medical Center, Rochester, NY.
authors.forename: Adan Z
authors.initials: AZ
authors.lastname: Becerra
authors.affiliation: Surgical Health Outcomes & Research Enterprise (SHORE), University of Rochester Medical Center, Rochester, NY.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Aquina
authors.affiliation: Department of Medicine, Hematology/Oncology Division, University of Rochester Medical Center, Rochester, NY.
authors.forename: Mohamedtaki A
authors.initials: MA
authors.lastname: Tejani
authors.affiliation: Department of Colorectal Surgery, Digestive Disease Institute, Cleveland Clinic Florida, Weston, FL.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Wexner
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY.
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia-Aguilar
authors.affiliation: Department of Colorectal Surgery, Digestive Disease Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Feza H
authors.initials: FH
authors.lastname: Remzi
authors.affiliation: Department of Colorectal Surgery, Digestive Disease Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: David W
authors.initials: DW
authors.lastname: Dietz
authors.affiliation: Surgical Health Outcomes & Research Enterprise (SHORE), University of Rochester Medical Center, Rochester, NY.
authors.forename: John R T
authors.initials: JR
authors.lastname: Monson
authors.affiliation: Surgical Health Outcomes & Research Enterprise (SHORE), University of Rochester Medical Center, Rochester, NY. Electronic address: fergal_fleming@URMC.rochester.edu.
authors.forename: Fergal J
authors.initials: FJ
authors.lastname: Fleming
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D059186:Chemoradiotherapy, Adjuvant; D016208:Databases, Factual; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome