STATIC AND DYNAMIC VASCULAR IMPACT OF LARGE ARTERY IRRADIATION

Purpose: To evaluate functional post-radiotherapy arterial change in a select patient population. Methods and Materials: Thirty-five seminoma patients were identified in the Radiation Oncology departmental records at Indiana University Medical Center. In this group the ipsilateral pelvis is treated with the contralateral pelvis available for evaluation as a matched control. Additionally, this group is generally young and unlikely to have pre-existing vascular disease, and shows excellent radiocurability with historically standard radiotherapy. Nineteen patients volunteered for a noninvasive vascular evaluation which included: Doppler ultrasound, segmental leg pressures, pulse volume recordings, and post-exercise testing. Average age at treatment was 36 (range 14-68) with an average follow-up of 8.8 years (range 1-20) with five patients now over 15 years post-treatment. The majority of the patients received 2500-2600 cGy. Results: Three of 19 patients had abnormal vascular evaluations. Of these, two had bilateral abnormalities not felt to be solely associated with irradiation. The remaining patient showed both resting and post-exercise ipsilateral vascular abnormalities. Irradiation was the only identifiable etiologic agent for this patient's vascular abnormality. Conclusion: Subclinical vascular change attributable to low dose radiotherapy was identified in one of 19 patients (5%). Considering the radiocurability of seminoma patients this incidence is acceptable. In light of this slight, yet documented, arterial abnormality occurring with low dose radiotherapy, we recommend additional study of high dose radiotherapy patients to determine the incidence and morbidity of radiation-induced arteriopathy in this group.