Between 1956 and 1988, 25 patients were treated with
radiotherapy for
acromegaly. Acromegalic features were present in 24 (96%), visual field deficits in 4 (16%), and suprasellar extension was present in 7 patients (28%). The median
growth hormone level was 40.2 ng/ml (range: 13.8-105) in 15 patients. Initial
therapy consisted of
radiotherapy alone (19 patients) or surgery followed at some interval by radiation (6 patients). The
radiation therapy was administered with megavoltage equipment in 23 (92%) patients and orthovoltage equipment in 2 patients. The median total dose was 46 Gy (range: 24-53.44 Gy) with 21 patients receiving at least 45 Gy. With a median follow-up of 53 months (range: 18-205), 2 of the 19 patients treated with
radiotherapy alone have required surgery for symptomatic recurrences. Both are alive and in remission at 69 and 158 months following
craniotomy. Thus, the success of
radiotherapy as a primary modality in this series is 17/19 (89%). None of the six patients treated postoperatively have recurred. At the time of last follow-up the visual fields remained normal and visual acuity stable in the 21 patients with no pre-existing visual deficits. The four patients with prior visual field deficits improved with
therapy. There were no cases of radiation
optic neuropathy, brain
necrosis or second intracranial
malignancies. Seven patients (28%) had evidence of
hypopituitarism attributed to the
radiotherapy.
Growth hormone levels after
radiotherapy showed a median of 5.4 ng/ml (range: 3.2-40.0) in 15 patients. Eleven of 15 patients (73%) had
growth hormone levels less than 10 ng/ml. Radiation use in
acromegaly remains a safe and effective modality assuming careful attention is paid to technique, total dose, and fraction size.