Volumetric Modulated Arc Therapy (VMAT) combined with deep inspiration breath hold (DIBH) technique for adjuvant irradiation for cancer of the left breast

Purpose: We describe here the implementation of a very simple approach of combining Volumetric Arc Therapy (VMAT) and the deep inspiration breath hold technique (DIBH) without any costly equipment, in order to reduce the dose at the heart and decrease the cardiotoxicity risk for left sided breast radiotherapy (RT). Methods and Materials: Forty nine patients were treated with the DIBH-VMAT technique with fractions of 2-2.7 Gy for Local (L) RT and fractions of 2Gy for Loco regional (LR) RT. DIBHVMAT plans were optimized with an arrangement of 4 arcs with a maximum delivery time of 25s each, and dosimetries were compared to 16 patients who received adjuvant irradiation (L or LR) with a free breathing (FB) VMAT. Results: DIBH-VMAT technique reduced the heart mean dose (Dmean) below 2Gy for L and LR RT and reduced the Dmean at the contra-lateral organs especially for lung with an inexistent V5Gy.The ipsilateral lung Dmean achieved was 6.4Gy±1.6Gy and 9.8Gy±1.2Gy for L-RT and LR-RT, respectively. Conclusion: The VMAT-DIBH technique was successfully implemented without a dedicated breath hold equipment, which makes it a non-costly method. We achieved a good PTV coverage with important dose reductions especially at the heart, while preserving lungs and contralateral structures.