Dose-modeling study to compare external beam techniques from protocol NSABP B-39/RTOG 0413 for patients with highly unfavorable cardiac anatomy

Journal Article · Tue Aug 01 04:00:00 EDT 2006 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2006.03.060· OSTI ID:20850016

Hiatt, Jessica R ^[1]; Evans, Suzanne B ^[2]; Price, Lori Lyn ^[2]; Cardarelli, Gene A ^[1]; Di Petrillo, Thomas A ^[1]; Wazer, David E ^[3]

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1. Department of Radiation Oncology, Rhode Island Hospital, Brown University School of Medicine, Providence, RI (United States)
2. Department of Radiation Oncology, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, MA (United States)
3. 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, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 5 Vol. 65; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
ANATOMY
BEAMS
CHEST
CLINICAL TRIALS
DISEASE INCIDENCE
HEALTH HAZARDS
IRRADIATION
MAMMARY GLANDS
MORTALITY
MYOCARDIUM
NEOPLASMS
PATIENTS
RADIATION DOSES
RADIOTHERAPY
SIMULATION
SURGERY
TOXICITY