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 seminom a patients were identified in the Radiation Oncology departmental reco rds at Indiana University Medical Center. In this group the ipsilatera l pelvis is treated with the contralateral pelvis available for evalua tion as a matched control. Additionally, this group is generally young and unlikely to have pre-existing vascular disease, and shows excelle nt radiocurability with historically standard radiotherapy. Nineteen p atients volunteered for a noninvasive vascular evaluation which includ ed: Doppler ultrasound, segmental leg pressures, pulse volume recordin gs, 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 p atients now over 15 years post-treatment. The majority of the patients received 2500-2600 cGy. Results: Three of 19 patients had abnormal va scular evaluations. Of these, two had bilateral abnormalities not felt to be solely associated with irradiation. The remaining patient showe d both resting and post-exercise ipsilateral vascular abnormalities. I rradiation was the only identifiable etiologic agent for this patient' s vascular abnormality. Conclusion: Subclinical vascular change attrib utable to low dose radiotherapy was identified in one of 19 patients ( 5%). Considering the radiocurability of seminoma patients this inciden ce is acceptable. In light of this slight, yet documented, arterial ab normality occurring with low dose radiotherapy, we recommend additiona l study of high dose radiotherapy patients to determine the incidence and morbidity of radiation-induced arteriopathy in this group.