title: Tumor regression grades: can they influence rectal cancer therapy decision tree?
abstract: BACKGROUND
  Evaluating impact of tumor regression grade in prognosis of patients with locally advanced rectal cancer (LARC).
  
  
  METHODS
  We identified from our colorectal cancer database 168 patients with LARC who received neoadjuvant therapy followed by complete mesorectum excision surgery between 2003 and 2011: 157 received 5-FU-based chemoradiation (CRT) and 11 short course RT. We excluded 29 patients, the remaining 139 were reassessed for disease recurrence and survival; the slides of surgical specimens were reviewed and classified according to Mandard tumor regression grades (TRG). We compared patients with good response (Mandard TRG1 or TRG2) versus patients with bad response (Mandard TRG3, TRG4, or TRG5). Outcomes evaluated were 5-year overall survival (OS), disease-free survival (DFS), local, distant and mixed recurrence.
  
  
  RESULTS
  Mean age was 64.2 years, and median followup was 56 months. No statistically significant survival difference was found when comparing patients with Mandard TRG1 versus Mandard TRG2 (p = .77). Mandard good responders (TRG1 + 2) have significantly better OS and DFS than Mandard bad responders (TRG3 + 4 + 5) (OS p = .013; DFS p = .007).
  
  
  CONCLUSIONS
  Mandard good responders had a favorable prognosis. Tumor response (TRG) to neoadjuvant chemoradiation should be taken into account when defining the optimal adjuvant chemotherapy regimen for patients with LARC.
authors.affiliation: Digestive Surgery Service, Department of Surgery, Hospital de Santo António, Largo Professor Abel Salazar, 4099-003 Porto, Portugal.
authors.forename: Marisa D
authors.initials: MD
authors.lastname: Santos
authors.forename: Cristina
authors.initials: C
authors.lastname: Silva
authors.forename: Anabela
authors.initials: A
authors.lastname: Rocha
authors.forename: Eduarda
authors.initials: E
authors.lastname: Matos
authors.forename: Carlos
authors.initials: C
authors.lastname: Nogueira
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy / Q000379:methods; D003663:Decision Trees; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012004:Rectal Neoplasms / Q000628:therapy*; D012074:Remission Induction