In acromegaly, radiation therapy can realize a reduction in GH excess of 30-50% in the first year, followed by 10-15% in the years thereafter. Despite the development of potent medical therapies and the improvement of neurosurgical techniques at least 10-20% of patients will need any form of radiation therapy. In addition to decreasing GH excess, radiation therapy has been shown to influence favourably the clinical consequences of the reduction in soft tissue excess, visual symptoms, headache and glucose intolerance, thereby confirming a favourable impact on the disease21.