Impact of Radiotherapy on Malfunctions and Battery Life of Cardiac Implantable Electronic Devices in Cancer Patients

SIMPLE SUMMARY: Ionizing radiotherapy (RT) can cause malfunctions to cardiac implantable electronic devices (CIEDs), posing a risk to patient safety. The aim of the study was to quantify and categorize the risk of CIED malfunction during RT and to analyze national guidelines/recommendations for adequate patient safety. We found that the CIED malfunction rate is low (2.8%) in cancer patients receiving RT. The probability of CIED malfunction does not correlate with the applied photon energy, the dose at the CIED nor the treated area. Battery depletion occurs very rarely (1.2%). The national guidelines strongly differ in regard to safety the recommendations for patients with a CIED during and after RT. ABSTRACT: Purpose: This study analyses a large number of cancer patients with CIEDs for device malfunction and premature battery depletion by device interrogation after each radiotherapy fraction and compares different guidelines in regard to patient safety. Methods: From 2007 to 2022, a cohort of 255 patients was analyzed for CIED malfunctions via immediate device interrogation after every RT fraction. Results: Out of 324 series of radiotherapy treatments, with a total number of 5742 CIED interrogations, nine device malfunctions (2.8%) occurred. Switching into back-up/safety mode and software errors occurred four times each. Once, automatic read-out could not be performed. The median prescribed cumulative dose at planning target volume (PTV) associated with CIED malfunction was 45.0 Gy (IQR 36.0–64.0 Gy), with a median dose per fraction of 2.31 Gy (IQR 2.0–3.0 Gy). The median maximum dose at the CIED at time of malfunction was 0.3 Gy (IQR 0.0–1.3 Gy). No correlation between CIED malfunction and maximum photon energy (p = 0.07), maximum dose at the CIED (p = 0.59) nor treatment localization (p = 0.41) could be detected. After excluding the nine malfunctions, premature battery depletion was only observed three times (1.2%). Depending on the national guidelines, 1–9 CIED malfunctions in this study would have been detected on the day of occurrence and in none of the cases would patient safety have been compromised. Conclusion: Radiation-induced malfunctions of CIEDs and premature battery depletion are rare. If recommendations of national safety guidelines are followed, only a portion of the malfunctions would be detected directly after occurrence. Nevertheless, patient safety would not be compromised.