Abstract
This case study explores the strategic decision-making and safety considerations in managing a unique scenario where a pacemaker dependent patient, requiring adjuvant radiotherapy for bilateral breast cancer. The conventional pacemaker was located entirely within the treatment target, without the option for transposition because of the bilateral chest treatment, resulting in significant risk of malfunction caused by exposing it to the full prescribed dose. Consequently, the decision was made to replace the conventional pacemaker with a leadless device Micra implanted directly into the heart to mitigate direct device radiation and potential adverse effects of proton therapy on the cardiac device. Following Micra implantation, the patient underwent the proton treatment without complications or serious device malfunctions. This study explores solutions to address the challenges posed by within-the-field cardiac devices and highlights the use of pencil beam proton therapy for individuals with leadless cardiac devices while acknowledging the potential for neutron production and the associated risk of single-event upsets (SEU) in cardiac implantable electronic devices (CIEDs). The findings underscore the significance of strategic decision-making, risk assessment, and continuous monitoring for successful outcomes, particularly in the context of proton therapy for patients with advanced cardiac considerations.