Patient Specific Heart Constraint: A tool for optimisation and evaluation of mean heart dose in breast cancer patients.

Abstract Purpose/Objective Our institution introduced a Patient-Specific Heart Constraint (PSHC) and a mean heart dose (MHD) constraint of 4Gy for all patients receiving breast radiation therapy (RT) with a simultaneous boost (SIB). This was introduced as a method to calculate the predicted MHD before optimising IMRT fields. We sought to determine whether the introduction of a PSHC reduced MHD, whilst maintaining optimally-dosed treatment plans. Material/Methods Patients were retrospectively divided into two groups, pre- and post-introduction of the PSHC. The breast and SIB Planning Target Volumes (PTVs) were prescribed to 50Gy and 57Gy respectively, in 25 fractions. Plans were generated using a hybrid IMRT technique, 30Gy using an open tangential field arrangement, and 27Gy using IMRT fields. The PSHC was calculated using: MHD of open tangential field x 2. A paired t-test compared PTV coverage and heart doses between cohorts (p Results A total of 264 patients were included (138 pre-PSHC and 126 post-PSHC) with 137 right-sided and 127 left-sided treatments. MHD was significantly reduced across both right (-.04 Gy p Conclusion Introduction of a PSHC can reduce MHD and V5 Gy for patients receiving whole breast RT with SIB, whilst maintaining optimally-dosed plans, with the greatest benefit shown for left-sided, free-breathing treatments.