Irradiation treatment of laryngeal cancer in a patient with an implantable cardioverter-defibrillator (ICD)

Background: Due to an aging population the incidence of both
cardiac and tumor-related illnesses is increasing. A problem may
arise if radiotherapy is necessary in close anatomic proximity to
an implantable cardioverter-defibrillator (ICD). These highly
precise devices may respond to ionizing radiation with a loss of
function or uncontrolled stimulation, with both effects being
potentially life threatening. Available guidelines recommend the
dose maximum to a pacemaker to be cumulative below 2 Gy. For most
patients undergoing radiation therapy of the neck or of the chest
this limit is exceeded, thus making a removal of the device and an
implantation of an external ICD necessary. Case Report: A patient
with severe cardiac problems underwent an implantation of an ICD.
However, a recurrence of a laryngeal cancer was diagnosed. The
irradiation dose after resection was 60 Gy to the tumor region and
50 Gy to the lymph nodes. Irradiation peakload to the ICD was
calculated to be 2.5 Gy. This dose was verified with
thermoluminescence measurements. The ICD was externally deactivated
during the sessions of irradiation. Device checks demonstrated no
malfunction. Conclusion: Even though the dose limits of the ICD of
2 Gy were exceeded, the device demonstrated a regular function
during and after radiotherapy.