title: Impact of pathological characteristics on local relapse after breast-conserving therapy: a subgroup analysis of the EORTC boost versus no boost trial.
abstract: OBJECTIVE
  To investigate the long-term impact of pathologic characteristics and an extra boost dose of 16 Gy on local relapse, for stage I and II invasive breast cancer patients treated with breast conserving therapy (BCT).
  
  
  METHODS
  In the European Organisation for Research and Treatment of Cancer boost versus no boost trial, after whole breast irradiation, patients with microscopically complete excision of invasive tumor, were randomly assigned to receive or not an extra boost dose of 16 Gy. For a subset of 1,616 patients central pathology review was performed.
  
  
  RESULTS
  The 10-year cumulative risk of local breast cancer relapse as a first event was not significantly influenced if the margin was scored negative, close or positive for invasive tumor or ductal carcinoma in situ according to central pathology review (log-rank P = .45 and P = .57, respectively). In multivariate analysis, high-grade invasive ductal carcinoma was associated with an increased risk of local relapse (P = .026; hazard ratio [HR], 1.67), as was age younger than 50 years (P < .0001; HR, 2.38). The boost dose of 16 Gy significantly reduced the local relapse rate (P = .0006; HR, 0.47). For patients younger than 50 years old and in patients with high grade invasive ductal carcinoma, the boost dose reduced the local relapse from 19.4% to 11.4% (P = .0046; HR, 0.51) and from 18.9% to 8.6% (P = .01; HR, 0.42), respectively.
  
  
  CONCLUSIONS
  Young age and high-grade invasive ductal cancer were the most important risk factors for local relapse, while margin status had no significant influence. A boost dose of 16 Gy significantly reduced the negative effects of both young age and high-grade invasive cancer.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh Cancer Center, Pittsburgh, PA, USA.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Jones
authors.forename: Ninja
authors.initials: N
authors.lastname: Antonini
authors.forename: Augustinus A M
authors.initials: AA
authors.lastname: Hart
authors.forename: Johannes L
authors.initials: JL
authors.lastname: Peterse
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Horiot
authors.forename: Françoise
authors.initials: F
authors.lastname: Collin
authors.forename: Philip M
authors.initials: PM
authors.lastname: Poortmans
authors.forename: S Bing
authors.initials: SB
authors.lastname: Oei
authors.forename: Laurence
authors.initials: L
authors.lastname: Collette
authors.forename: Henk
authors.initials: H
authors.lastname: Struikmans
authors.forename: Walter F
authors.initials: WF
authors.lastname: Van den Bogaert
authors.forename: Alain
authors.initials: A
authors.lastname: Fourquet
authors.forename: Jos J
authors.initials: JJ
authors.lastname: Jager
authors.forename: Dominic A X
authors.initials: DA
authors.lastname: Schinagl
authors.forename: Carla C
authors.initials: CC
authors.lastname: Wárlám-Rodenhuis
authors.forename: Harry
authors.initials: H
authors.lastname: Bartelink
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000517:prevention & control; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D016896:Treatment Outcome