title: Radiation dose distribution in functional heart regions from tangential breast cancer radiotherapy.
abstract: To analyze the distribution of individually-determined radiation dose to the heart and its functional sub-structures after radiotherapy in breast cancer patients treated in Germany during 1998-2008.
  
  
  
  We obtained electronic treatment planning records for 769 female breast cancer patients treated with megavoltage tangential field radiotherapy. All dose distributions were re-calculated using Eclipse with the anisotropic analytical algorithm (AAA) for photon fields, and the electron Monte Carlo algorithm for electron boost fields. Based on individual dose volume histograms for the complete heart and several functional sub-structures, we estimated various dose measures in patient groups.
  
  
  
  Mean heart dose spanned a range of 0.9-19.1Gy for left-sided radiotherapy and 0.3-11.6Gy for right-sided radiotherapy. Average (median) mean heart dose was 4.6Gy (3.7Gy) for left-sided radiotherapy, and 1.7Gy (1.4Gy) for right-sided RT. With left-sided radiotherapy, 66% of the patients had 2cm(3) of the complete heart exposed to at least 40Gy. Younger age, higher body mass index, tumor location in a medial quadrant, and presence of a parasternal field were also associated with higher heart dose.
  
  
  
  Tumor location and treatment choices influence cardiac dose with complex interactions. There is considerable variability in heart dose, with dose metrics of different cardiac sub-structures showing different patterns in their dependency on external influences. Dose-response analysis of late cardiac effects after radiotherapy requires detailed individual dosimetry.
authors.affiliation: Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Germany. Electronic address: wollschlaeger@uni-mainz.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wollschläger
authors.affiliation: Department of Radiation Oncology, University Medical Center Mainz, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Karle
authors.affiliation: Department of Radiation Oncology, University Medical Center Mainz, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Stockinger
authors.affiliation: Department of Radiation Oncology, University Hospital Ulm, Germany.
authors.forename: Detlef
authors.initials: D
authors.lastname: Bartkowiak
authors.affiliation: Department of Radiation Oncology, University Hospital Ulm, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Bührdel
authors.affiliation: Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Germany.
authors.forename: Hiltrud
authors.initials: H
authors.lastname: Merzenich
authors.affiliation: Department of Radiation Oncology, University Hospital Ulm, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wiegel
authors.affiliation: Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Blettner
authors.affiliation: Department of Radiation Oncology, University Medical Center Mainz, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Schmidberger
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D008875:Middle Aged; D009010:Monte Carlo Method; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted
keywords: Breast cancer; Dose–volume histogram; Dosimetry; Heart dose