Radiation Therapy in Patients with Implanted Cardiac Pacemakers and Implantable Cardioverter Defibrillators: A Prospective Survey in Japan

Patients with implanted cardiac pacemakers (ICPs) or implantable cardioverter defibrillators (ICDs) are increasing in number, and the incidence of treating these patients with radiation therapy also is increasing. Thus, a prospective survey was conducted of patients with these devices receiving radiation therapy. A prospective survey of patients with ICPs or ICDs treated with radiation therapy was conducted on methods of radiation therapy, status of ICP/ICD, and management of patients before, during, and after radiation therapy. After completion of radiation therapy, study participants were registered via mail, fax, or e-mail. Sixty-two patients from 29 institutions were registered from September 2006 to December 2008. Sixty patients had an ICP and 2 had an ICD. The total dose was estimated before radiation therapy by dose-volume histogram in 26 patients (42%) and by measurement of actual doses in 9 (15%). In one patient, the maximum total dose was 2069 cGy; however, in the other patients, the ICP/ICD dose did not exceed 478 cGy. Function of ICPs and ICDs was checked before radiation therapy in 38 patients (61%), after radiation therapy in 32 (52%), and both before and after radiation therapy in 29 (47%). ICP malfunction occurred in a patient with prostate cancer treated by intensity-modulated radiation therapy to the prostate. Even when an ICP or ICD is not within the field of radiation, malfunction of the device may still occur. To minimize the risk to patients, precautions must be taken during the planning and administration of radiation therapy.