Intensity-modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation: initial report.
OBJECTIVE
This study was designed to compare the dose received by the contralateral breast during primary breast irradiation using intensity-modulated radiotherapy with the dose received via conventional tangential field techniques.


METHODS
Between March 2003 and March 2004, 44 patients with breast carcinoma were treated using 6-, 10-, or mixed 6/18-MV photons(36 with tangential intensity-modulated radiotherapy technique and eight with three-dimensional technique using tangential fields with wedges) for primary breast irradiation after breast-conserving surgery. Paired thermoluminescent dosimeters were placed on each patient's contralateral breast, 4 cm from the center of the medial border of the tangential field. The thermoluminescent dosimeters were left on the patient during a single fraction and then measured 24 hours later.


RESULTS
The mean dose delivered with photons to the primary breast for all patients was 4998 cGy [SD = 52], and the mean single fraction dose was 200 cGy [SD = 9]. The mean percent of the prescribed dose to the contralateral breast was 7.74% (SD = 2.35) for patients treated with intensity-modulated radiotherapy, compared with 9.74% [SD = 2.04] for the patients treated with conventional tangential field techniques. This represented a 20% reduction in the mean dose to the contralateral breast with the use of intensity-modulated radiotherapy when compared with the dose received via the three-dimensional technique, a result that was statistically significant.


CONCLUSIONS
Primary breast irradiation with tangential intensity-modulated radiotherapy technique significantly reduces the dose to the contralateral breast when compared with conventional tangential techniques.
Bhatnagar
Ajay K
AK
Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232, USA.
Brandner
Edward
E
Sonnik
Deborah
D
Wu
Andrew
A
Kalnicki
Shalom
S
Deutsch
Melvin
M
Heron
Dwight E
DE
D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000517:prevention & control*; D016609:Neoplasms, Second Primary / Q000517:prevention & control*; D011446:Prospective Studies; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000009:adverse effects* / Q000379:methods*; D014057:Tomography, X-Ray Computed