title: Evaluation of current consensus statement recommendations for accelerated partial breast irradiation: a pooled analysis of William Beaumont Hospital and American Society of Breast Surgeon MammoSite Registry Trial Data.
abstract: OBJECTIVE
  To determine whether the American Society for Radiation Oncology (ASTRO) Consensus Statement (CS) recommendations for accelerated partial breast irradiation (APBI) are associated with significantly different outcomes in a pooled analysis from William Beaumont Hospital (WBH) and the American Society of Breast Surgeons (ASBrS) MammoSite® Registry Trial.
  
  
  METHODS
  APBI was used to treat 2127 cases of early-stage breast cancer (WBH, n=678; ASBrS, n=1449). Three forms of APBI were used at WBH (interstitial, n=221; balloon-based, n=255; or 3-dimensional conformal radiation therapy, n=206), whereas all Registry Trial patients received balloon-based brachytherapy. Patients were divided according to the ASTRO CS into suitable (n=661, 36.5%), cautionary (n=850, 46.9%), and unsuitable (n=302, 16.7%) categories. Tumor characteristics and clinical outcomes were analyzed according to CS group.
  
  
  RESULTS
  The median age was 65 years (range, 32-94 years), and the median tumor size was 10.0 mm (range, 0-45 mm). The median follow-up time was 60.6 months. The WBH cohort had more node-positive disease (6.9% vs 2.6%, P<.01) and cautionary patients (49.5% vs 41.8%, P=.06). The 5-year actuarial ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), and distant metastasis (DM) for the whole cohort were 2.8%, 0.6%, 1.6%. The rate of IBTR was not statistically higher between suitable (2.5%), cautionary (3.3%), or unsuitable (4.6%) patients (P=.20). The nonsignificant increase in IBTR for the cautionary and unsuitable categories was due to increased elsewhere failures and new primaries (P=.04), not tumor bed recurrence (P=.93).
  
  
  CONCLUSIONS
  Excellent outcomes after breast-conserving surgery and APBI were seen in our pooled analysis. The current ASTRO CS guidelines did not adequately differentiate patients at an increased risk of IBTR or tumor bed failure in this large patient cohort.
authors.affiliation: Department of Radiation Oncology, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan, USA.
authors.forename: J Ben
authors.initials: JB
authors.lastname: Wilkinson
authors.forename: Peter D
authors.initials: PD
authors.lastname: Beitsch
authors.forename: Chirag
authors.initials: C
authors.lastname: Shah
authors.forename: Doug
authors.initials: D
authors.lastname: Arthur
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Haffty
authors.forename: David E
authors.initials: DE
authors.lastname: Wazer
authors.forename: Martin
authors.initials: M
authors.lastname: Keisch
authors.forename: Simona F
authors.initials: SF
authors.lastname: Shaitelman
authors.forename: Maureen
authors.initials: M
authors.lastname: Lyden
authors.forename: Peter Y
authors.initials: PY
authors.lastname: Chen
authors.forename: Frank A
authors.initials: FA
authors.lastname: Vicini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008875:Middle Aged; D001918:Brachytherapy / Q000379:methods; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D015331:Cohort Studies; D008207:Lymphatic Metastasis; D015412:Mastectomy, Segmental; D016609:Neoplasms, Second Primary; D017410:Practice Guidelines as Topic; D018787:Radiation Oncology; D020266:Radiotherapy, Conformal / Q000379:methods; D012042:Registries; D012955:Societies, Medical; D047368:Tumor Burden; D003245:Consensus Statements as Topic