Utility of Deep inspiration breath-hold for left sided breast radiation therapy in preventing early cardiac perfusion defects - A Prospective Study

Abstract Purpose To evaluate early cardiac single photon computed tomography (SPECT) findings after left breast/chest wall postoperative radiation therapy (RT) in the setting of deep inspiration breath hold (DIBH). Methods We performed a prospective single-institution- single arm study of patients who were planned for tangential RT with DIBH to the left breast/chest wall (+/- internal mammary nodes). Deep inspiration breath hold was done utilizing a controlled surface monitoring technique (AlignRT, Vision RT Ltd., London, UK). Radiation therapy was given with tangential fields and a heart block. Radiation-induced cardiac perfusion and wall-motion changes were assessed using pre-RT and 6 month post-RT SPECT scans. A cumulative SPECT summed-rest score (SRS) was used to quantify perfusion in predefined left ventricle segments. The incidence of wall-motion abnormalities was assessed in each of these same segments. Results A total of 20 patients with normal pre-RT scans were studied; median age 56 years (range, 39-72). Seven (35%) patients were also irradiated to left internal mammary chain, and 5 (25%) had an additional RT field to supraclavicular nodes. Median heart dose 94cGy (range, 56-200), median V25Gy was zero (range, 0-0.1). None of the patients had post-RT perfusion or wall motion abnormalities. Conclusions Our results suggest that DIBH and conformal cardiac blocking for patients receiving tangential RT for left-sided breast cancer is an effective means to avoid early RT-associated cardiac perfusion defects.