Endocrine Abstracts

Introduction: Sterotactic radiosurgery (SR) has been used to treat recurrent adenomas after failure of medical and surgical procedures and also as a primary treatment. The aim of this paper is to evaluate long-term control of functioning pituitary adenomas (FPA).

Patients and method: Thirty-eight patients with FPA treated with modified linear accelerator (LINAC) between 1998 and 2009 in three tertiary Spanish hospitals. Hormonal control was defined as hormonal normalization. Control of tumor size was defined as an unchange/decrease of tumor size.

Results: The average follow-up period was 7.3 years. The cohort consisted of 78.9% of women and 21.1% of men with an average age of 39.9 years. LINAC was the primary treatment in 16 patients, while the remaining 22 patients had undergone one/two prior surgical resections. There were 4 prolactinomas, 17 adrenocorticotropic hormone-secreting and 17 GH secreting tumors. Prior to radiosurgery, pituitary hormone deficits were observed in 23.6% of patients. New endocrine deficits occurred of 75–82.3% patients during the follow-up. Seven patients achieved remission after SR treatment. The mean dose of treatment was 17 Gy. Tumor volume decreased in 68.4% patients, increased in 5.2% of patients, and was unchanged in 26.3% of patients. Three patients presented cognitive deterioration after radiosurgery and two acromegaly patients suffered strokes two and three years after radiosurgery. The decrease in levels of IGF1 and 24 h urine cortisol after 3 months of SR was statistically significant (P=0.011 and P=0.017 respectively), but not in prolactine levels (P=0.144). There were no differences between radiosurgery as primary or adjuvant treatment.

Conclusions: LINAC resulted in a durable rate of tumor control in 94.7% of patients with FPA; nevertheless hormonal normalization without treatment is more difficult to reach. Follow-up is important to detect new hormonal deficits and other side effects that may appear in the long term.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.