ENDOCRINE FACTORS INFLUENCING RADIATION-INJURY TO CENTRAL NERVOUS-TISSUE

Corticosteroids have been shown experimentally to lower the tolerance of various normal tissues (lung, kidney, intestine) to irradiation. Pre-existing hypertension also modifies the effect of irradiation on the rat spinal cord and brain. Hypercorticism and hypertension co-exist in patients with Cushing's disease. Although these patients are often approached therapeutically by irradiation, no reports concerning differences in the radiation sensitivity of nervous tissue between normal subjects (non-functioning pituitary adenomas) and those with hormonal imbalance and/or hypertension appear to be available. A comprehensive review of the literature revealed 14 patients with radiation damage to brain or to optic pathways following moderate doses for pituitary adenomas. Seven of the 14 patients (50%) had Cushing's disease. This apparent higher incidence of radiation injury is significant if we consider that less than 5% of all patients receiving irradiation for pituitary adenomas have Cushing's disease. © 1979.