• Kyle E Rusthoven, Dennis L Carter, Kathryn Howell, Jane M Kercher, Phyllis Henkenberns, Kari L Hunter, and Charles E Leonard.
• Department of Radiation Oncology, University of Colorado Health Sciences Center, Denver, CO, USA.
• Int. J. Radiat. Oncol. Biol. Phys. 2008 Jan 1; 70 (1): 296-302.

PurposeTo compare dose distribution and normal tissue sparing in partial-breast treatment using three-dimensional conformal radiotherapy (3D-CRT) vs. intensity-modulated radiotherapy (IMRT).Methods And MaterialsSixty-three patients with Tis-1N0M0 breast cancer were treated on a Phase II prospective accelerated partial-breast IMRT protocol at two facilities between April 2004 and January 2006. Fifty-six patients had data sets sufficient to adequately contour all structures. These cases were subsequently replanned with 3D-CRT techniques using the same contours, to compare the dose distribution patterns of 3D-CRT vs. IMRT.ResultsThe average planning target volume (PTV) to ipsilateral breast (IB) ratio was 24% (range, 7-58%). The average volume of IB receiving 25%, 50%, 75%, and 100% of the prescribed dose was 4.0%, 5.0%, 5.5%, and 10.5% less with IMRT than with 3D (p < 0.01). The dose reduction to normal breast was further improved in the subset of patients whose PTV to IB ratio was >25%, and in patients with contoured breast volume <750 cm(3). No difference was detected in delivery to the lumpectomy cavity or clinical target volume. The PTV volume receiving 95% of the dose was higher in the 3D conformal plans (p < 0.01), but no significant difference was observed in the PTV volume receiving 90% (p = 0.17). The irradiated heart and lung volumes were small with both techniques but also favored IMRT.ConclusionsIn T1N0 patients treated with external beam partial-breast radiotherapy, IMRT improves normal tissue sparing in the ipsilateral breast compared with 3DRT, without compromising dose delivery to the lumpectomy cavity and clinical target volume.

26 keywords...

hide…