Conventional Supervoltage Irradiation Is an Effective Treatment for Acromegaly

Abstract

Forty-seven acromegalic patients were treated with conventional supervoltage irradiation (4000-5000 rads) and were followed-up at 2, 5, and 10 yr after treatment. The mean fall in theGH concentrations 5 years after treatment was 77%, and GH was less than 10 ng/ml in 73% of the cases. In the majority, GH continued to fall over the 5- to 10-yr interval after treatment,so that by 10 yr, plasma GH was ≤10 ng/ml in 81% and ≤5 ng/ml in 69% of thepatients. Also, the subjective (acral and facial changes) and theobjective (metabolic) effects of GH excess all showed significant improvement with time, and the improvement roughly paralleled the fall in plasma GH concentrations. After therapy, no patient developed extrasellar extension, and headaches improved in the majority of patients. The prevalence of hypopituitarism, which was low before treatment, increased progressively throughout the follow-up period. Significant loss of vision was observed in only one patient, who received 5600 rads and had severe systemic sarcoidosis. The only other complication was temporal hair loss. Conventional supervoltage irradiation by 5-10 yr produces the same fall in plasma GH as all other forms of treatment for acromegaly, including transphenoidal microsurgery.The rate of fall in plasma GH after conventional irradiation is comparable to that of more aggressive forms of irradiation and is slower than that achieved by surgical methods but probably conventional irradiation has fewer serious side effects.