Results of continuous long-term intravenous application of octreotide via an implantable pump system in acromegaly resistant to operative and X-ray therapy.

Long term results after surgery for growth hormone (GH)-secreting adenomas indicate only a limited cure rate, particularly in patients with tumours invading the dural boundaries of the sella with suprasellar extension. Since octreotide had become a treatment option, it was used i.v. via an implantable pump system in five patients (age range 24-46 yr) showing symptoms of uncontrolled acromegaly, in spite of previous surgery and X-ray therapy. The octreotide doses used permanently for a cumulative treatment period of 8.8 yr ranged between 300 and 1000 micrograms/24 h. Serial evaluations of clinical findings, 24-h GH and insulin profiles, insulin growth factor-1 (IGF-1), oral glucose tolerance test and pituitary function revealed sustained GH suppression, without interim escape, below 2 ng/ml in two and below 5 ng/ml in three patients, IGF-1 decrease in all with normalization in two patients and no clinically relevant disturbances of carbohydrate tolerance or thyroid-stimulating hormone secretion. In one case of previous unresponsiveness to dopamine agonists i.v. octreotide application for 29 months facilitated later disease control by bromocriptine only. In two patients octreotide was terminated after 15 and 30 months of i.v. administration, respectively, because the effects of irradiation had occurred. For a subgroup of patients with resistant acromegaly continuous i.v. octreotide can be considered as a safe and effective alternative, which increases patients' independency from the inconvenience of daily repeated s.c. injections.