Endocrine Abstracts

Introduction

Yttrium-90 pituitary implants were used in the past as one of the first line treatments for pituitary tumours in many endocrine centres. The procedure involved inserting radioactive rods of Yttrium oxide in to the pituitary fossa. This treatment has been replaced by medical treatment for prolactinomas and transsphenoidal surgery for all other pituitary tumours.

Aim

To investigate long-term efficacy of Yttrium-90 implantation for pituitary tumours.

Methods

We conducted a retrospective audit of 76 patients that had Yttrium-90 implantation for a pituitary tumour who were identified from our Hospitals database. Data was collected from 1954 to 2006. Remission rates of pituitary tumours were defined as percentage of patients who had either pan-hypopituitarism, partial hypopituitarism or normal pituitary function after primary treatment with Yttium-90. Deficiencies of specific pituitary hormones were also recorded.

Results

Remission rates of 81%, 75% and 67% after an average number of years of follow-up of 27.5±1.5 years, 25±1.5 years and 27.3±1.2 years for ACTH, PRL and GH secreting adenomas respectively. Normal pituitary function was achieved in 29% of PRL secreting adenomas, 26% of GH adenomas and 10% of ACTH secreting adenomas. Pan-hypopituitarism was defined as deficiency of more than 3 pituitary hormones and occurred in 42% of ACTH secreting adenomas, 19% in GH secreting adenomas and 13% in PRL secreting adenomas treated with Yttrium-90. Remission rates for pituitary tumours treated with transsphenoidal surgery are reported in the literature to range from 59%–82% and remission rates for patients treated with medical therapy of prolactinomas range from 53% - 83%.

Conclusion

Yttrium-90 pituitary implants appeared to have been an effective treatment modality for pituitary tumours after over 25 years of follow-up for ACTH, PRL and GH secreting pituitary tumours. It compares favourably with current first line treatments for pituitary adenomas.