title: Tumor regression grade in gastric cancer: Predictors and impact on outcome.
abstract: BACKGROUND
  The clinical value and prognostic implications of histologic response to neoadjuvant chemotherapy in gastric cancer is unknown.
  
  
  METHODS
  Tumor regression grade (TRG) was recorded in 58 gastric cancer patients identified from two institutional surgical databases. TRG 1a/b represented histologic responders (<10% viable tumor), while TRG 2/3 represented non-responders (>10% viable tumor).
  
  
  RESULTS
  TRG 1a/b was recorded in 10 patients (17%), while 48 patients (83%) had a TRG 2/3 response. Larger tumor size (OR 0.24; 95%CI 0.09, 0.64; P = 0.004) and clinical downstaging (OR 30.0; 95%CI 3.26, 276; P = 0.003) were the only factors predictive of histologic response. TRG 1a/b responders had 3-year survival of 70.0% and an estimated overall survival of >69.8 months compared to 38.2% and 22.8 months in non-responders; however, this trend was not statistically significant (P = 0.535). While TRG could not predict survival (OR 2.40; 95%CI 0.46, 12.57; P = 0.300), patient age (OR 1.06; 95%CI 1.00, 1.11; P = 0.035), and the number of positive lymph nodes (≥7; OR 0.05; 95%CI 0.07, 0.27; P < 0.001) were independent predictors of survival.
  
  
  CONCLUSIONS
  Few gastric cancers demonstrate histologic response to neoadjuvant chemotherapy. While TRG may be a valid marker for treatment response, its predictive value and clinical application in gastric cancer remains unclear. J. Surg. Oncol. 2016;114:434-439. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Gastrointestinal Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Aaron U
authors.initials: AU
authors.lastname: Blackham
authors.affiliation: Department of Surgery, Penn State Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Erin
authors.initials: E
authors.lastname: Greenleaf
authors.affiliation: Department of Gastrointestinal Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Maki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Surgery, Penn State Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Chris
authors.initials: C
authors.lastname: Hollenbeak
authors.affiliation: Department of Surgery, Penn State Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Niraj
authors.initials: N
authors.lastname: Gusani
authors.affiliation: Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, Florida.|Department of Tumor Biology, Moffitt Cancer Center, Tampa, Florida.|Department of Chemical Biology and Molecular Medicine, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Domenico
authors.initials: D
authors.lastname: Coppola
authors.affiliation: Department of Gastrointestinal Oncology, Moffitt Cancer Center, Tampa, Florida.|Department of Tumor Biology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Pimiento
authors.affiliation: Department of Surgery, Penn State Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Joyce
authors.initials: J
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology* / Q000628:therapy
keywords: gastric cancer; neoadjuvant therapy; survival; tumor regression grade