Mean radiation dose to the heart in patients with left breast cancer with and without breath-hold technique.

Abstract

85 Background: Mean heart dose (MHD) from breast irradiation has been correlated with late risk of ischemic heart disease. We previously reported using 3-D conformal radiation with field-in-field forward planning and heart blocking; MHD is substantially lower than described for patients treated before 2001. To further reduce MHD, we treated eligible patients with left breast cancer with breath hold technique. We compared the MHD with and without breath hold technique. Methods: We reviewed 45 radiation treatment plans of patients treated to the left breast from 5/2013-5/2014. All patients were evaluated for breath hold technique. Criteria were ability to hold the breath for 20 seconds and a stable chest position. 18 patients were treated with breath hold (BH), 27 patients with non-breath hold (NBH). All treatment plans were CT-based, 3-D conformal with field-in- field forward planning and heart blocking. Two treatment regimens were used: hypofractionation (HF) (16 x 2.66 Gy, no boost) or standard fractionation (SF) (46.8-50.4 Gy, +/- 10 Gy boost). Fisher's exact test and t-test were used to assess the data between MHD with breath hold (BH) and without (NBH). Results: Average MHD was 1.03 Gy (0.59-1.7) in BH patients, in comparison to 1.57 Gy (0.89-2.50) in NBH patients p<0.0001). MHD was associated with total breast dose (p=0.01) and BH patients were younger, average age 55.78 years (21.41-48.37) vs NBH, average 62.78 years (38-82). There was no association between breath hold and BMI. BH BMI average 34.12 (21.41-48.37), NBH average BMI 32.6 (20.58-44.71) p=0.46. Conclusions: Patients treated with radiation to the left breast with breath hold technique had significantly lower MHD than those treated with non-breath hold. (p=0.0001) Breath hold eligible patients tended to be younger; there was no relation between breath hold eligibility and BMI.