Evaluation of Heart Dose for Left-Sided Breast Cancer Patients Over an 11-Year Period Spanning the Transition From 2-Dimensional to 3-Dimensional Planning.
We evaluated heart dose from left breast radiotherapy with 2-dimensional (2D) versus 3-dimensional (3D) plans.



Treatment plans from patients treated with standard fractionation for left breast cancer from 2003 to 2013 were reviewed, with patients grouped into 3 cohorts: 2003 to 2004 ("2D", with computed tomography scans for dose calculation but fields defined using simulation films; n = 29), 2005 to 2006 ("2D-post," after several influential articles on heart dose were published; n = 31), and 2007 to 2013 ("3D"; n = 256). All patients were treated with free-breathing technique. Heart volumes were retrospectively contoured for the earlier 2 cohorts. Mean heart dose (MHD) and percentage of structure receiving at least 25 Gy (V25 Gy) and percentage of structure receiving at least 5 Gy for the whole heart, left ventricle (LV), right ventricle (RV), and both ventricles were recorded and compared among cohorts.



MHD was 345 cGy (2D), 213 cGy (2D-post) and 213 cGy (3D). LV V25 Gy was 6.3%, 1.5%, and 1.1%, respectively. Lower doses were seen over time for all indices (analysis of variance, P < .0001). Post hoc tests indicated significantly higher doses for 2D versus 2D-post or 3D cohorts (P ≤ .001) for all parameters except RV V25 Gy (P = .24).



Heart doses were higher with 2D versus 3D plans. Cardiac doses and resulting toxicity with modern 3D planning might be lower than those in previous reports.
Department of Radiation Oncology, University of California San Francisco, San Francisco, CA. Electronic address: Jennifer.s.chang@ucsf.edu.
Jennifer S
JS
Chang
Department of Radiation Oncology, University of California San Francisco, San Francisco, CA.
Josephine
J
Chen
Department of Radiation Oncology, University of California San Francisco, San Francisco, CA.
Vivian K
VK
Weinberg
Department of Radiation Oncology, University of California San Francisco, San Francisco, CA.
Barbara
B
Fowble
John Muir Medical Center, Walnut Creek, CA.
Rajni A
RA
Sethi
D001940:Breast / Q000000981:diagnostic imaging; D019583:Dose Fractionation, Radiation; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D021621:Imaging, Three-Dimensional; D011832:Radiation Injuries / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D000069584:Unilateral Breast Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*
Breast cancer; Heart dose; Radiation planning; Radiotherapy