Author(s):
1. Drazan Jaros, University Medical Center Groningen, Netherlands
2. Petar Janjic, IMC Banja Luka, Republic of Srpska, Bosnia and Herzegovina
3. Tatjana Ignjić, IMC Banja Luka - Affidea, Republic of Srpska, Bosnia and Herzegovina
4. Goran Kolarević, Republic of Srpska, Bosnia and Herzegovina

Abstract:
Background/Aim: For women with left sided breast cancer, a major concern is the dose of radiation delivered to the heart. In order to reduce the dose to the heart during tangential breast irradiation, in our institution we implemented a deep inspiration breath hold (DIBH) technique. Aim of this retrospective study was to compare dosimetric effects of the DIBH on the heart, left anterior descending artery (LAD) and ipsilateral lung (IL) planned with hybrid plan (IMRT+VMAT), IMRT and conformal-forward IMRT plans. Methods: Twenty patients who underwent RT with DIBH at our institution were retrospectively analysed. Conformal plans consisted of two opposed tangential segmented 6MV beams and one direct beam with small dose contribution. Hybrid plan consisted of two tangential IMRT 6MV beams with 90% of the dose contribution and two 180° arcs (6MV) with 10% of the dose contribution. IMRT plan consisted of two opposed tangential beams. Doses to the planning target volume (PTV), clinical target volume (CTV), heart, LAD, IL and contralateral breast were assessed. Results: Dosimetric comparison between hybrid, IMRT and conformal DIBH radiotherapy for mean dose to the heart was 2.42Gy vs. 1.64Gy (p=0.03) vs. 2.88Gy (p=0.137), and the mean percentage of the volume receiving 25Gy was 0.54% vs. 0.77% (p=0.832) vs. 0.85% (p=0.04), respectively. radiotherapy Mean PTV coverage was 98.98% vs. 96.38% (p<0.001) vs. 96.33% (p<0.001), mean CTV coverage was 99.49% vs 98.79% (p<0.001) vs. 97.85% (p<0.001) for hybrid, IMRT and conformal treatment plans, respectively. Mean dose for LAD was 7.73Gy vs. 7.33Gy (p<0.001) vs. 11.88Gy (p<0.001). Mean percentage of the volume receiving 20Gy for the IL was 12.06% vs. 12.09% (p<0.001) vs. 13.26% (p<0.001) for hybrid, IMRT and conformal plans, respectively. Mean percentage of the volume receiving 5Gy for the contralateral breast was 1.71% vs. 1.52% (p<0.001) vs. 0.81% (p=0.002) for hybrid, IMRT and conformal treatment planning, respectively. Mean percentage of the volume receiving 10Gy for the contralateral breast was 0.40% vs. 0.69% (p=0.363) vs. 0.49% (p=0.414) for hybrid, IMRT and conformal techniques, respectively. Conclusion: Comparison of three planning techniques showed better target coverage for hybrid radiotherapy plans. Hybrid and IMRT planning and delivery reduces the dose delivered to the heart, LAD and ipsilateral lung. IMRT Conformal planning technique showed better results for contralateral breast.

Key words:
Breast cancer radiotherapy, Deep inspiration breath hold, Hybrid planning

Date of abstract submission:
17.08.2023.

Conference:
Contemporary Materials 2023 - Savremeni materijali

Applied paper from author