Efficacy of Conventional Pituitary Irradiation in Acromegaly

Abstract

External irradiation of the pituitary gland with 4000 Ft from a conventional supervoltage source reduced plasma growth hormone in 19 of 20 patients with acromegaly. By one to two years after irradiation, the mean fall in plasma hormone concentration for the entire group was 51 per cent (range, 0 to 88 per cent). In seven patients who were studied again at two and a half to four years, the mean decrease was 76 per cent (60 to 89 per cent). Of seven untreated but otherwise comparable patients, one had a slight reduction, one had no change, and five had rises in plasma hormone concentrations over similar periods of observation. The only complication of irradiation was hair loss at the temples. The falls in plasma growth hormone and the wide variation in benefit among individual patients that we observed with conventional external irradiation are indistinguishable from results reported by others for proton-beam irradiation, implants of radioactive yttrium, cryohypophysectomy and surgical hypophysectomy.