Radiation injury involving the internal carotid artery. Report of two cases

Radiation therapy is an uncommon cause of stenosis and occlusions of the cervical internal carotid artery (ICA). We describe two cases of cerebral ischemia due to ICA stenosis in patients irradiated for malignant tumors (lymphoma and breast cancer). The first patient, a 32-year-old man, presented with an episode of cerebral ischemia. Six years previously he had received irradiation therapy for a left laterocervical mass histologically diagnosed at biopsy as a Hodgkin's lymphoma. Cerebral angiography on entry revealed bilateral occlusion of the cervical ICA, with a 2-cm stump at the origin of the left ICA. Despite anti-platelet aggregation therapy the ischemic attacks persisted, necessitating a stumpectomy. After vascular-repair surgery the patient had no further ischemic symptoms. The second patient, a 42-year-old woman, began to experience the sudden onset of pain in the right arm and left hemiparesis five years after surgery plus irradiation (4500 rad) for breast cancer, and three years after excision of a single cerebral metastasis. Cerebral angiography obtained on admission showed occlusion of the right ICA and right subclavian arteries, both lesions necessitating thrombectomy. After surgery the right radial pulse immediately re-appeared and the hemiparesis regressed. In both patients, 2-year follow-up assessment by Doppler ultrasonography and magnetic resonance angiography (MRA) confirmed that the operated arteries remained patent. These two unusual cases underline the potential risk of irradiation-induced ischemic cerebrovascular symptoms, suggesting that patients who have received radiation therapy to the neck and mediastinum who survive for more than 5 years should undergo regular non-invasive imaging of neck vessels (Doppler ultrasonography and MRA).