Endocrine Abstracts

Long-term review of 21 acromegalic patients with yttrium-90 implants

CNL Jayasena, C Wujanto, JF Todd & K Meeran

Imperial College, London, United Kingdom.

Background: Yttrium-90 (90Y) pituitary implants have previously been used to treat patients with growth hormone (GH) secreting pituitary adenoma. This study reports the long-term effect of 90Y implants on growth hormone levels and pituitary function in a group of acromegalic patients.

Methods: A retrospective study of 21 acromegalic patients (male, 10; female, 11) with 90Y pituitary implants was undertaken. All pituitary implants were performed between 1966 and 1987, with the mean length of time since implantation being 30.1 years. The mean age of at first implantation was 62.8 years.

Results: Disease remission (mean GH<2 mIU/l) was achieved in 7 out of 17 patients (41.2%) patients after one 90Y pituitary implant. In the 2 patients with two implants each, one had complete remission and the other had external-beam radiotherapy before complete remission. In the 2 patients with three implants each, one had complete remission and the other had GH recurrence 26 years after the third implant. Four out of 17 patients who received only one implant required subsequent radiotherapy to achieve disease remission. Seven patients currently require further medications to control disease activity. Regarding pituitary function, a total of 17 patients are on replacement therapy (hydrocortisone, 14; prednisolone, 2; thyroxine, 14, testosterone, 7, oestrogen 2). Overall, GH levels gradually declined throughout with time (mean GH at 41.1 mIU/l at one year post-90Y, 8.8 mIU/l at 10 years post-90Y, 3.7 mIU/l at 20 years post-90Y and 1.6 mIU/l at 30 years post-90Y).

Conclusion: Pituitary implantation with 90Y steadily decreased GH levels in patients with acromegaly. However, this only occurred over a period of 20 years, with two-thirds of patients requiring adjunctive therapy to control GH levels. In addition, most patient required long-term pituitary replacement therapy.

Endocrine Abstracts (2005) 10 P54