Objectives: The purpose of our evaluation was to assess efficacy and safety of radiosurgery and hypofractionated radiotherapy in patients suffering from functioning pituitary adenomas (somatotropinomas, adenocorticotropinomas, prolactinomas and mixed-type adenomas) treated at our institution between 2001 and 2011.

Methods: Data of 96 patients treated with the use of linac-based SRS or HFSRT for pituitary adenoma were analysed retrospectively. Functioning adenomas were diagnosed in 66 cases. The mean and median follow-up was 6.6 and 6.4 years, respectively. Doses were applied in 1 to 3 fractions of 4 to 22 Gy. Mean total dose for growth hormone secreting adenomas was 13.6 Gy, for adrenocorticotropinomas - 12.3 Gy, and for prolactin-producing adenomas it was 11.8 Gy. Local control was defined as a stabilization or regression of tumor mass visualized on MR or CT scans. Hormonal response was defined as normalization of secretion or reduction of at least 50% of the initial level of the hypersecreted hormone.

Results: Local control in growth hormone and prolactin producing adenomas was 100%. In adrenocorticotropic hormone producing adenomas stabilization or regression in tumour size was observed in 89%. Hormonal response was confirmed in 57% of GH-producing, 30% of ACTH-producing and 25% of PRL-producing adenomas. The most common complication was hypopituitarism, found in 22% of GH-active, in 11% of ACTH-active and in 25% of PRL-active tumours. Mild ophtalmological disturbances were noticed in 2 patients after the treatment. In one slight progression of a preexisting central scotoma. In the other, non-characteristic visual field deficits of uncertain relation to the treatment because the first perimetry in this patient was performed during follow-up after radiosurgery.

Conclusions: Functioning pituitary adenomas as a group of variable entities require individualised treatment. Lower doses of radiation allow for efficient hormonal and local control in acromegalic patients. In case of Cushing’s disease and hyperprolactinemia, probably higher doses are necessary to achieve satisfactory results in terms of hormonal control. Patients with secreting pituitary adenomas are prone to secondary hypopituitarism after radiosurgery.