Heart dose reduction by prone deep inspiration breath hold in left-sided breast irradiation.

Abstract

Cardiac disease has been related to heart dose after left-sided breast radiotherapy. This trial evaluates the heart sparing ability and feasibility of deep inspiration breath hold (DIBH) in the prone position for left-sided whole breast irradiation (WBI). Twelve patients underwent CT-simulation in supine shallow breathing (SB), supine DIBH, prone SB and prone DIBH. A validation cohort of 38 patients received prone SB and prone DIBH CT-scans; the last 30 patients were accepted for prone DIBH treatment. WBI was planned with a prescription dose of 40.05 Gy. DIBH was able to reduce (p<0.001) heart dose in both positions, with results for prone DIBH at least as favorable as for supine DIBH. Mean heart dose was lowered from 2.2 Gy for prone SB to 1.3 Gy for prone DIBH (p<0.001), while preserving the lung sparing ability of prone positioning. Moreover prone DIBH nearly consistently reduced mean heart dose to less then 2 Gy, regardless of breast volume. All patients were able to perform the simulation procedure, 28/30 patients were treated with prone DIBH. This trial demonstrates the ability and feasibility of prone DIBH to acquire optimal heart and lung sparing for left-sided WBI.