title: Predicting Heart Dose in Breast Cancer Patients Who Received 3D Conformal Radiation Therapy.
abstract: Cardiac late effects are a major health concern for long-term survivors after radiotherapy for breast cancer. Large cohort studies to better understand the exact dose-response relationship require individual estimates of radiation dose to the heart. To predict individual cardiac dose from information that is typically available for all members of a retrospective epidemiological cohort study, 774 female breast cancer patients treated with megavoltage tangential field radiotherapy in 1998-2008 were examined. All dose distributions were 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, the authors calculated absorbed dose in the complete heart as well as in six functional substructures. Statistical models were developed to predict absorbed dose using only covariate information from patients' clinical records on tumor location, patient anatomy and radiotherapy prescription. The out-of-sample prediction error for mean heart dose was 54% (coefficient of variation). The prediction error in functional substructures ranged from 49-68% for mean dose and from 52-86% for extreme dose. The authors conclude that based on a patient sample with exact heart dosimetry, it is possible to use clinical information alone to predict absorbed heart dose in the remaining cohort with a quantified error suitable for dose-response analyses of cardiac late effects.
authors.affiliation: *Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Mainz, Germany; †Department of Radiation Oncology, University Medical Center Mainz, Mainz, Germany; ‡Department of Radiation Oncology, University Hospital Ulm, Ulm, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wollschläger
authors.forename: Heiko
authors.initials: H
authors.lastname: Karle
authors.forename: Marcus
authors.initials: M
authors.lastname: Stockinger
authors.forename: Detlef
authors.initials: D
authors.lastname: Bartkowiak
authors.forename: Sandra
authors.initials: S
authors.lastname: Bührdel
authors.forename: Hiltrud
authors.initials: H
authors.lastname: Merzenich
authors.forename: Thomas
authors.initials: T
authors.lastname: Wiegel
authors.forename: Heinz
authors.initials: H
authors.lastname: Schmidberger
authors.forename: Maria
authors.initials: M
authors.lastname: Blettner
mesh_terms: D065638:Absorption, Radiation; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D015995:Prevalence; D011379:Prognosis; D000069079:Radiation Exposure / Q000032:analysis / Q000706:statistics & numerical data*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data*; D050397:Radiotherapy, Intensity-Modulated; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity