Initial dosimetric experience using simple three-dimensional conformal external-beam accelerated partial-breast irradiation.
OBJECTIVE
Several accelerated partial-breast irradiation (APBI) techniques are being investigated in patients with early-stage breast cancer. We present our initial experience using three-dimensional conformal radiation therapy (3D-CRT).


METHODS
Sixty-one patients with tumors of 2 cm or less and negative axillary nodes were treated with 3D-CRT accelerated partial-breast irradiation (APBI) between August 2003 and March 2005. The prescribed radiation dose was 32 Gy in 4-Gy fractions given twice daily. Efforts were made to minimize the number of beams required to achieve adequate planning target volume (PTV) coverage.


RESULTS
A combination of photons and electrons was used in 85% of patients. A three-field technique that consisted of opposed, conformal tangential photons and enface electrons was employed in 43 patients (70%). Nine patients (15%) were treated with a four-field arrangement, which consisted of three photon fields and enface electrons. Mean PTV volumes that received 100%, 95%, and 90% of the prescribed dose were 93% +/- 7%, 97% +/- 4%, and 98% +/- 2%, respectively. Dose inhomogeneity exceeded 10% in only 7 patients (11%). Mean doses to the ipsilateral lung and heart were 1.8 Gy and 0.8 Gy, respectively.


CONCLUSIONS
Simple 3D-CRT techniques of APBI can achieve appropriate PTV coverage while offering significant normal-tissue sparing. Therefore, this noninvasive approach may increase the availability of APBI to patients with early-stage breast cancer.
Taghian
Alphonse G
AG
Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA. ataghian@partners.org
Kozak
Kevin R
KR
Doppke
Karen P
KP
Katz
Angela
A
Smith
Barbara L
BL
Gadd
Michele
M
Specht
Michelle
M
Hughes
Kevin
K
Braaten
Kristina
K
Kachnic
Lisa A
LA
Recht
Abram
A
Powell
Simon N
SN
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D004583:Electrons / Q000627:therapeutic use; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D017785:Photons / Q000627:therapeutic use; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*