Safety of Radiotherapy in Patients with Cardiac Implantable Electronic Devices

Abstract Background: Patients with cardiac implantable electronic devices (CIEDs) usually have multiple comorbidities, and some require radiotherapy (RTx) for cancer treatment. However, the effect of RTx in patients with CIEDs is unclear. We aimed to examine the effectiveness of RTx in patients with CIEDs, and share our real-world clinical experience in this population.Methods: We recruited patients with a pacemaker or implantable cardioverter-defibrillator who underwent RTx between April 2009 and August 2019. RTx and CIED interrogation data were collected from electronic medical records. Patients who received an RTx cardiology consultation and CIED interrogation before and after RTx were assigned to the proper consultation (PC) group. All others were enrolled in the no-consultation (NC) group. Results: Out of 23 patients, 3 (13.0%) and 20 (87.0%) patients were assigned to the PC and NC groups, respectively. The most common RTx sites were the abdomen and pelvis (34.8%). The mean cumulative dose was 50.1 ± 11.7 Gy, and the mean beam energy was 10.3 ± 4.01 mV. The PC and NC groups showed no significant difference in cumulative dose (51.5 ± 12.1 vs. 45.3 ± 3.9, p=0.19) or beam energy (10.4 ± 4.03 vs. 7.0 ± 1.41, p=0.08). There was no significant between-group difference in any pre-RTx CIED parameter. Two patients died during the study period; both were in the NC group. The relationship between death and device malfunction was not clear in either case.Conclusions: Patients with CIEDs frequently do not receive a cardiology consultation before RTx. Although radiotherapy-related CIED complications occur stochastically and are difficult to predict, cooperation between the cardiology and radiation therapy departments, and regular device follow-up are necessary for the safety of these patients.