title: Effect of age and radiation dose on local control after breast conserving treatment: EORTC trial 22881-10882.
abstract: OBJECTIVE
  To determine whether the effect of an additional "boost" radiation after breast conservative therapy (BCT) on local control depends on age and evaluate the impact of a treatment policy with a threshold for age.
  
  
  METHODS
  We used data from EORTC 22881-10882 trial, with median follow-up of 77.4 months. Patients receiving BCT and 50Gy whole breast irradiation were randomized to no boost and 16Gy boost (N=5318).
  
  
  RESULTS
  In univariate analysis, a boost reduced local failure by a factor of 2 (P<0.0001). Multivariate analysis showed local control increased with age (P=0.0003). There was no evidence that the relative effect of a boost on local control depends on age (P=0.97) However in younger patients the 5-year local failure was higher, therefore the absolute reduction was greater. If the threshold-age for boost treatment were set at 40 years, 8.4% of the study population would receive a boost, resulting in a 5-year local failure of 6.1% in the study population. Changing the threshold-age to 60 years, 67% of the study population would receive a boost and the 5-year local failure would be reduced to 4.4%.
  
  
  CONCLUSIONS
  In younger patients a boost dose resulted in a greater absolute reduction of local failure. The relative risk reduction was however similar for all ages. Applying a treatment policy with a threshold-age of 60 would result in 0.6% increase in local failure in the total study population, while sparing the boost to 1/3 of the patients.
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Ninja
authors.initials: N
authors.lastname: Antonini
authors.forename: Heather
authors.initials: H
authors.lastname: Jones
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Horiot
authors.forename: Philip
authors.initials: P
authors.lastname: Poortmans
authors.forename: Henk
authors.initials: H
authors.lastname: Struikmans
authors.forename: Walter
authors.initials: W
authors.lastname: Van den Bogaert
authors.forename: Isabelle
authors.initials: I
authors.lastname: Barillot
authors.forename: Alain
authors.initials: A
authors.lastname: Fourquet
authors.forename: Jos
authors.initials: J
authors.lastname: Jager
authors.forename: Willem
authors.initials: W
authors.lastname: Hoogenraad
authors.forename: Laurence
authors.initials: L
authors.lastname: Collette
authors.forename: Marianne
authors.initials: M
authors.lastname: Pierart
authors.forename: Guus
authors.initials: G
authors.lastname: Hart
authors.forename: Harry
authors.initials: H
authors.lastname: Bartelink
mesh_terms: D000328:Adult; D000367:Age Factors; D000971:Antineoplastic Combined Chemotherapy Protocols; D001943:Breast Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D003520:Cyclophosphamide; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005472:Fluorouracil; D006801:Humans; D015412:Mastectomy, Segmental; D008727:Methotrexate; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011878:Radiotherapy / Q000379:methods; D011879:Radiotherapy Dosage; D012306:Risk
chemical_list: D003520:Cyclophosphamide; D005472:Fluorouracil; D008727:Methotrexate