title: Association between maximal skin dose and breast brachytherapy outcome: a proposal for more rigorous dosimetric constraints.
abstract: OBJECTIVE
  Multiple investigations have used the skin distance as a surrogate for the skin dose and have shown that distances <6 mm have been associated with late toxicity after MammoSite brachytherapy. No publications have yet described the relationship between the actual maximal skin dose and the outcome. The present study analyzed the maximal skin dose delivered and the occurrence of late toxicity in a large cohort of patients with prolonged follow-up.
  
  
  METHODS
  A total of 96 patients treated with breast brachytherapy between 2000 and 2007 for whom complete planning and follow-up data were available were included in the present analysis. The median follow-up was 48 months (range, 24-111). Of the 96 patients, 40 were treated with multicatheter interstitial brachytherapy and 56 with MammoSite. A multivariate statistical analysis was performed to determine the relationship between several dosimetric parameters and patient outcome.
  
  
  RESULTS
  The treatment was well tolerated, with 98% of patients experiencing good to excellent cosmesis. Significant late toxicity was uncommon. The maximal dose delivered to the skin was significantly associated with the incidence of any degree of telangiectasia (p = .009) and moderate to severe fibrosis (p = .010). The incidence of late toxicity was significantly increased when the dose to the skin was >4.05 Gy/fraction.
  
  
  CONCLUSIONS
  The initial skin dose recommendations have been based on safe use and the avoidance of significant toxicity. The results from the present study have suggested that patients might further benefit if more rigorous constraints were applied and if the skin dose were limited to 120% of the prescription dose.
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Medical College of Virginia Campus, 401 College St., Box 980058, Richmond, VA 23298, USA. lcuttino@mcvh-vcu.edu
authors.forename: Laurie W
authors.initials: LW
authors.lastname: Cuttino
authors.forename: Jill
authors.initials: J
authors.lastname: Heffernan
authors.forename: Robyn
authors.initials: R
authors.lastname: Vera
authors.forename: Mihaela
authors.initials: M
authors.lastname: Rosu
authors.forename: V Ramesh
authors.initials: VR
authors.lastname: Ramakrishnan
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Arthur
mesh_terms: D001918:Brachytherapy / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D015999:Multivariate Analysis; D011832:Radiation Injuries / Q000473:pathology*; D011879:Radiotherapy Dosage; D012867:Skin / Q000033:anatomy & histology / Q000528:radiation effects*; D013684:Telangiectasis / Q000209:etiology / Q000473:pathology; D035441:Thoracic Wall / Q000528:radiation effects