A prospective study on the need of gated (GAT) radiotherapy in left sided breast cancer patients treated at the Technical University Munich (TUM) The GATTUM Trial: Study Protocol (Preprint)

Abstract

Abstract:Background: Deep inspiration breathhold (DIBH) it is the most widely used technique for heart sparing.Nonetheless, treatment preparation, patient coaching and treatment planning/ delivery can be more time consuming than conventional techniques. The aim of our study is to find predictive measurements that will allow an estimation of the heart dose reduction by DIBH and thus allow a precise selection of these patients. Methods:The GATTUM trial is a single institution, prospective pilot study. 150 breast cancer patients who will undergo radiotherapy at the university hospital 'Klinikum rechts der Isar' will be included in the study. All patients will undergo breathing triggered radiation planning with a CT during free breathing (FB) and a CT during deep inspiration breath hold (DIBH). Patients without cardiac risk factors with heart Dmean ≥ 3 Gy and for patients with cardiac risk factors with heart Dmean ≥ 2Gy are recommended to undergo radiation therapy in DIBH. The primary endpoint of the study is to identify measurements that will predict the heart dose reduction in DIBH. Secondary endpoints include quality of life and cosmesis. Discussion:The measurements that we aim to find by this study are to be performed on a planning CT or a diagnostic CT performed beforehand; easy to perform by each staff member; correlated with clinical data (such as breast size; heart and lung morphometry; heart and lung comorbidities) and correlated with the a 3D CRT tangential field "standard" dose distribution. This study could help to improve the knowledge about the necessity of respiratory-gated radiotherapy. We expect that evidence-based indications regarding optimization-criteria for radiation planning of breast cancer patients can be determined for the first time.