Program Information
The Comparison of Risk of Secondary Malignancies Arising From Five Different Whole Breast Radiation Treatments
D Kim1*, E Han2 , N Paudel2 , M HARDEE2 , W Chung1 , J Sung3 , M Yoon3 , (1) Kyung Hee University Hospital at Gangdong, Seoul, Korea,(2) University of Arkansas for Medical Science, Little Rock, AR, US,(3) Korea University, Seoul, Korea
Presentations
SU-E-T-728 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:This study aimed to compare estimates of secondary cancer risks using five radiotherapy modalities to treat breast cancer: intensity-modulated radiotherapy (IMRT), 3-dimensional conformal radiation therapy (3D-CRT), field-in-field forward-planned intensity-modulated radiation (FinF), volumetric modulated arc therapy (VMAT), and TomoHDA (TOMO).
Methods:Each of 10 selected breast patients was re-planned with the five different modalities. The planning target volume (PTV) was defined as the contoured breast subtracted 5 mm from the skin, and lungs, heart, and contralateral breast were contoured as OARs. The prescription (Rx) was 50.4 Gy in 28 fractions, which covered 95% of the PTV. Dose constraints for the contralateral lung of volumes receiving 20 Gy and 10 Gy (V20Gy and V10Gy) were less than 20% and 40%, respectively, a maximum cord dose less than 45 Gy and for the rest. Qrgan equivalent doses (OEDs), dose characteristics, and lifetime attributable risks (LARs) were derived from dose-volume histograms for in-field regions and radio-photoluminescence glass dosimeter (RPLGD) measurements for out-of-field regions.
Results: TOMO had a better target dose distribution than 3D-CRT and FinF. OEDs for TOMO were similar to those of 3D-CRT in in-field region but increased as distance from the field boundary increased. LARs of the lung and contralateral breast were highest for VMAT, followed by IMRT, FinF, 3D-CRT, and TOMO. IMRT and VMAT had a 40–50% lower in V20Gy than 3D-CRT.
Conclusion: Our results indicate that TOMO provides comparable plan quality for breast cancer radiotherapy compared to IMRT/VMAT, and, at the same time, the lowest cancer risk in in-field regions among all studied treatment modalities. Therefore TOMO could be a better alternative treatment modality than 3D-CRT for breast cancer patients.
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