RADIATION-THERAPY ALONE FOR GROWTH HORMONE-PRODUCING PITUITARY-ADENOMAS

We present our experience in the treatment of growth hormone (GH)-prod ucing pituitary adenomas using irradiation alone. Between 1983 and 199 1, 21 patients suffering from GH-secreting pituitary adenomas were tre ated with radiotherapy alone. Two bilateral opposing coaxial fields we re used in 10 patients and in the remaining 11 a third frontovertex fi eld was added. Treatment was given in 1.8-2 Gy daily fractions and tot al dose ranged between 45 and 54 Gy. Treatment was given using a cobal t unit. Four patients treated with somatostatin prior to and 14 patien ts treated after the end of radiotherapy experienced symptom relief fo r 6-28 weeks. The 5-year actuarial rate of disease control was 72%. Fi ve out of six failed patients;had macroadenomas. Hypopituitarism was o bserved in 5/21 (24%) patients. Whereas RT alone is effective in the t reatment of microadenomas, this is not true for large infiltrative mac roadenomas.