title: Comparison of tumor regression grade systems for locally advanced rectal cancer after multimodality treatment.
abstract: BACKGROUND
  Tumor regression grade (TRG) is a measure of histopathological response of rectal cancer to neoadjuvant chemoradiation and is associated with outcomes. Several TRG systems are used: Mandard (5,3-tier), Dowrak/Rödel (5,3-tier), Memorial Sloan Kettering Cancer Center (MSKCC), and American Joint Committee on Cancer (AJCC) Cancer Staging. A single measure of rectal cancer response would assist in comparing results across institutions, and in designing future rectal cancer studies. In this study, the predictive accuracies of the various published classification schemes are compared.
  
  
  METHODS
  Review of a prospective database identified 563 patients with locally advanced rectal cancer (T3/4 and/or N1) treated between 1998 and 2007 with long-course chemoradiation and total mesorectal excision. TRG was determined by measuring proportion of tumor mass replaced by fibrosis. Patients were classified into TRG schemes, which were compared by analyzing association with recurrence and survival using concordance index. Probabilities of recurrence-free survival were estimated using the Kaplan-Meier method. All statistical tests were two-sided.
  
  
  RESULTS
  All TRG systems were predictive of recurrence. Concordance indices of the three-tier Mandard, three-tier Dowrak/Rödel, three-tier MSKCC, and four-tier AJCC systems were: 0.665, 0.653, 0.683, and 0.694, respectively (higher number = better prediction). The AJCC system more accurately predicted recurrence than the three-tier Mandard (P = .002) or Dowrak/Rödel (P = .006) and had a higher concordance index than MSKCC, although this did not reach statistical significance (P = .068).
  
  
  CONCLUSIONS
  When classifying rectal cancer response to chemoradiation, the AJCC Staging Manual (7(th) edition) system is most accurate and should be adopted as the standard.
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Atthaphorn
authors.initials: A
authors.lastname: Trakarnsanga
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Mithat
authors.initials: M
authors.lastname: Gönen
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Jinru
authors.initials: J
authors.lastname: Shia
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Garrett M
authors.initials: GM
authors.lastname: Nash
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Larissa K
authors.initials: LK
authors.lastname: Temple
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: José G
authors.initials: JG
authors.lastname: Guillem
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Philip B
authors.initials: PB
authors.lastname: Paty
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Karyn A
authors.initials: KA
authors.lastname: Goodman
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Abraham
authors.initials: A
authors.lastname: Wu
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Marc
authors.initials: M
authors.lastname: Gollub
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Neil
authors.initials: N
authors.lastname: Segal
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Leonard
authors.initials: L
authors.lastname: Saltz
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia-Aguilar
authors.affiliation: Colorectal Service/Department of Surgery (AT, GMN, LKT, JGG, PBP, JGA, MRW), Department of Epidemiology-Biostatistics (MG), Department of Pathology (JS), Department of Radiation Oncology (KAG), Department of Medicine (AW, NS, LS), and Department of Radiology (MG), Memorial Sloan Kettering Cancer Center, New York, NY. weiser1@mskcc.org.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Weiser
mesh_terms: D000328:Adult; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D003131:Combined Modality Therapy; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D012074:Remission Induction; D014481:United States