Inevitable high-dose irradiation to lead of implantable cardioverter defibrillator in small cell lung cancer: a case report

BACKGROUND: Radiotherapy has been shown to cause malfunction of implantable cardioverter-defibrillators, and there are few studies of implantable cardioverter-defibrillators and radiotherapy. We report an unusual case of small cell lung cancer in a patient with an implantable cardioverter-defibrillator in whom direct irradiation to the electrode and lead could not be avoided. CASE PRESENTATION: We report a case of radiotherapy in a 72-year-old Korean man with a limited stage of small cell lung cancer who had undergone insertion of an implantable cardioverter-defibrillator because of ventricular fibrillation. The radiation dose was 60 Gy in 30 fractions to the thorax. The mean dose and maximum dose estimated at the body of the implantable cardioverter-defibrillator were 0.89 Gy and 2.23 Gy, respectively. The mean and maximum doses of the lead and electrode were 17.12 Gy and 55.72 Gy in the lead and 1.81 Gy and 7.10 Gy in the electrode, respectively, because part of the lead and electrode was inevitably in the irradiated fields. The function of the patient’s implantable cardioverter-defibrillator was checked daily, and no change in implantable cardioverter-defibrillator function was observed for the duration of radiotherapy. The patient was tolerated the treatment well without severe complications. Computed tomography performed at 4 weeks after radiotherapy showed a good response with regression of the tumor. The patient was alive with complete remission of the tumor and without any implantable cardioverter-defibrillator dysfunction more than 36 months after the end of treatment. CONCLUSIONS: This case demonstrates that radiotherapy may be a safe and effective treatment modality through careful monitoring of implantable cardioverter-defibrillators in patients with lung cancer who have implantable cardioverter-defibrillators.