Reducing heart dose during left breast cancer radiotherapy: comparison among 3 radiation techniques.
OBJECTIVE
Breast cancer survivors have a high risk of cardiac death as a consequence of heart irradiation during left breast tangential radiotherapy (RT). This study compares the cardiac dose delivered by standard 3D conformal tangential RT (CRT) to that delivered by prospective-gating RT (PGRT) or 5-field intensity-modulated RT (IMRT).


METHODS
Patients with early left breast cancer, referred for adjuvant RT to our institution, were enrolled in this study. For each patient, 2 simulation computed tomography scans were acquired: the first during free breathing, and the second on prospective gating during deep inspiration breath-hold. The scans were monitored by the Varian RPM™ respiratory gating system. For each patient, 3 treatment plans were performed: a 3D-CRT and an IMRT plan, each based on the free-breathing scan, and a PGRT plan, based on the deep inspiration breath-hold scan. Dose-volume histograms were compared by means of the Friedman test.


RESULTS
The median mean heart dose was 3 Gy (range 0.9-7.3 Gy) in the CRT plans, 1.9 Gy (range 0.5-3.6 Gy) in the PGRT plans, and 4.5 Gy (range 1.1-10.5 Gy) in the IMRT plans (p = 0.001). The mean heart V25 was 1.2% (range 0%-9.7%), 0% (range 0%-2.0%), and 0.2% (range 0%-7.3%) for CRT, PGRT, and IMRT plans, respectively (p&lt;0.001).


CONCLUSIONS
Prospective-gating RT to the left breast offered the best protection of heart and lung, as well as a lower irradiation of the contralateral breast, compared to CRT or IMRT.
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Giuseppe R
GR
D'Agostino
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Barbara
B
Diletto
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Giovanna
G
Mantini
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Luigia
L
Nardone
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Gian Carlo
GC
Mattiucci
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Francesco
F
Catucci
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Roberta
R
Canna
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Antonella
A
Martino
Department of Physics, Catholic University of the Sacred Heart, Rome - Italy.
Luigi
L
Azario
Department of Radiation Oncology, Catholic University of the Sacred Heart, Rome - Italy.
Vincenzo
V
Valentini
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D062485:Breath Holding; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D001239:Inhalation; D008875:Middle Aged; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects / Q000379:methods; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects; D012119:Respiration