ESTRO 2021 Abstract Book

S540

ESTRO 2021

Figure 2: Selection of ROIs in breast cancer patients

Patient and Radiotherapy (RT) Treatment Data: Patient Data: •

Prospective evaluation of 44 consecutive left-sided breast cancer patients, mean age 63 years, 2 pts with bilateral breast cancer, 1 pt excluded (male, gynecomastia, total dose 20 Gy), total 43 pts • 41 pts with breast conserving surgery, 2 with mastectomy Treatment Data: • Mean dose 48 Gy, 31pts RT breast, 12 locoregional RT Results: Radiotherapy: • 34 with DIBH, 9 free breathing, 34 pts with modulated techniques (33 IMRT, 1 VMAT), 9 3D conformal • 28 pts with DIBH and modulated treatments, 6 pts with DIBH and conformal RT • 6 pts with free breathe and modulated treatments, 3 pts with free breathe and 3D conformal RT • Mean age DIBH 61 years, free breathe 68 years Heart and Lung Doses: • Mean heart dose 3D conformal 1.21 Gy, modulated technique 1.24 Gy • Mean lung dose 3D conformal 6.02 Gy, modulated technique 7.56 Gy • Mean heart dose DIBH 1.11 Gy, free breath 1.66 Gy • Mean lung dose DIBH 6.51 Gy, free breath 7.43 Gy Handling: • No additional time for patient positioning after learning phase • Treatment times longer with highly modulated technique and DIBH • Easy implementation in clinical routine • Reduction of skin markings • High acceptance of pts

Conclusion: •

Optimal sparing of normal tissue (heart and lung) with SGRT in DIBH • No influence of modulated versus 3D conformal techniques on normal tissue doses of the heart, but