The Indications for and Effects of Irradiation of the Pituitary Gland

The beneficial effect of deep X-ray irradiation on the size of pituitary tumours has been established beyond doubt. The effect of irradiation on the output of pituitary hormones is, however, much more questionable, and it is with this aspect of the problem that I wish to deal. The difficulty of assessing this effect is due partly to the fact that the measurement of pituitary hormone output is far more crude and inaccurate than is the measurement of the visual fields or the recognition of changes in the radiological appearance of the sella turcica, and partly to the fact that there is a considerable natural fluctuation in the severity of endocrine symptoms in the two hyperpituitary diseases acromegaly and basophilism. Moreover, Cushing (1912) pointed out that in acromegaly it is common to find symptoms of pituitary insufficiency developing as the tumour grows and crushes the remaining normal anterior lobe. It might be expected that effective X-ray irradiation would alter the cytological appearance in the anterior lobe, but I have examined the pituitary glands from a number of patients with inoperable brain tumours who had been treated with X rays, usually about 1600 r tumour dose, directed to the base of the brain, but I have never seen any changes which could be attributed to this treatment. Recently Goldberg and Lisser (1942) reported four cases of acromegaly treated by this method which had come to autopsy.