Dose-modeling study to compare external beam techniques from protocol NSABP B-39/RTOG 0413 for patients with highly unfavorable cardiac anatomy
- Department of Radiation Oncology, Rhode Island Hospital, Brown University School of Medicine, Providence, RI (United States)
- Department of Radiation Oncology, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, MA (United States)
- Department of Radiation Oncology, Rhode Island Hospital, Brown University School of Medicine, Providence, RI (United States) and Department of Radiation Oncology, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, MA (United States)
Purpose: The aim of this study was to select patients with heart anatomy that is specifically unfavorable for tangential irradiation in whole-breast radiotherapy (WBRT), to be used as an experimental cohort to compare cardiac dosimetric and radiobiological parameters of three-dimensional conformal external beam accelerated partial breast irradiation (3D-CRT APBI) to WBRT with techniques as defined by the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-39/Radiation Therapy Oncology Group (RTOG) 0413 clinical trial. Methods and Materials: A dosimetric modeling study that compared WBRT and 3D-CRT APBI was performed on CT planning data from 8 patients with left-sided breast cancer. Highly unfavorable cardiac anatomy was defined by the measured contact of the myocardium with the anterior chest wall in the axial and para-sagittal planes. Treatment plans of WBRT and 3D-CRT APBI were generated for each patient in accordance with NSABP B-39/RTOG 0413 protocol. Dose-volume relationships of the heart, including the V{sub 5}min (minimum dose delivered to 5% of the cardiac volume), biological effective dose (BED) of the V{sub 5}min, and normal tissue complication probability (NTCP) were analyzed and compared. Results: Despite expected anatomic variation, significantly large differences were found favoring 3D-CRT APBI in cumulative dose-volume histograms (p < 0.01), dose to the entire heart (mean difference 3.85 Gy, p < 0.01), NTCP (median difference, 1.00 Gy; p < 0.01), V{sub 5}min (mean difference, 24.53 Gy; p < 0.01), and proportional reduction in radiobiological effect on the V{sub 5}min (85%, p < 0.01). Conclusions: Use of 3D-CRT APBI can demonstrate improved sparing of the heart in select patients with highly unfavorable cardiac anatomy for WBRT, and may result in reduced risk of cardiac morbidity and mortality.
- OSTI ID:
- 20850016
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 65, Issue 5; Other Information: DOI: 10.1016/j.ijrobp.2006.03.060; PII: S0360-3016(06)00685-7; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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