Endocrine Abstracts

Background: The use of conventional radiotherapy (CR) in the treatment of pituitary adenomas has been associated with adverse effects such as development of hypopituitarism, cognitive impairment and optic nerve damage. Fractionated stereotactic conformal radiotherapy (FSRT) provides a new treatment regimen and was introduced at our University Hospital in 1996.

Objective: To evaluate the effects of FSRT on tumour size, hormonal overproduction and development of hypopituitarism and record other possible side-effects.

Methods: Between 1996 and 2004, 36 consecutive patients with pituitary adenomas were treated with FSRT. Of these patients, 21 patients had a non-functioning and 15 patients a functioning adenoma (7 GH-adenomas, 6 prolactinomas, 1 ACTH-adenoma, 1 FSH-adenoma). Thirty patients had been treated surgically 1–3 times before FSRT, the other 6 patients had not been operated before FSRT. Follow-up after FSRT ranged from 12 to 84 months. Clinical evaluation at the end of follow-up included use of a dopamine agonist or octreotide treatment, assessment of pituitary function and hormone replacement therapy and change in tumour size assessed by pituitary MRI.

Results: Preliminary tumour size data indicates that FSRT prevents further growth or reduces tumour size in most patients. In one patient with clear tumour growth after FSRT, histology of the pituitary adenoma revealed an atypic adenoma. Hormonal activity decreased in all patients with GH-adenomas but not in all patients with prolactinomas. After FSRT, further impairment of pituitary function was rare. FSRT was associated with allergy to the fixing mask in 1 case and a few patients reported tiredness or temporary hair loss.

Conclusions: FSRT seems to efficiently prevent further growth or reduce tumour size in most patients treated. FSRT decreases GH secretion in GH-adenomas. FSRT is safe and well-tolerated.