By Liz Meszaros
PHILADELPHIA -- May 5, 2010 -- Gamma-knife radiosurgery may effectively achieve tumour control in patients who have recurrent residual pituitary adenoma, researchers stated here at the 2010 Annual Meeting of the American Association of Neurological Surgeons (AANS).
"Radiosurgery is an excellent treatment option for patients with recurrent or residual pituitary tumours," noted investigator Jason P. Sheehan, MD, PhD, University of Virginia, Charlottesville, Virginia, speaking here on May 3. "It offers a high rate of tumour and endocrine control. As such, it allows most patients to avoid repeat open surgery or lifelong, expensive medical management."
Dr. Sheehan and colleagues conducted a single-centre retrospective study of the largest group of radiosurgery patients with a pituitary adenoma to date. In all, 418 patients who had undergone gamma-knife radiosurgery were followed for a minimum of 6 months (median 31 months). Factors related to endocrine remission, control of tumour growth, and development of pituitary deficiency were analysed.
Tumour control was achieved in 90.3% of patients, and higher radiation doses significantly resulted in tumour shrinkage. In patients with secretory pituitary adenoma, such as seen in Cushing's disease or acromegaly, median time to endocrine remission was 48.9 months.
Tumour-margin radiation dose was inversely correlated with time to achievement of endocrine remission (P < .05). Smaller adenoma size correlated with improved endocrine response in patients with secretory adenomas.
"Smaller tumour size improves the chances of endocrine control and lowers the risk of new pituitary hormone deficiency following stereotactic radiosurgery. A higher radiosurgical dose offers a greater chance of endocrine and tumour control," Dr. Sheehan noted.
New-onset pituitary hormone deficiency following surgery was seen in 24.4% of patients. There were no cases of panhypopituitarism, and 1 case of posterior pituitary insufficiency. Treatment with pituitary-hormone suppressive medication at the time of surgery was related to a loss of pituitary function (P < .05).
"Radiosurgery has become an increasingly important technique for the treatment of recurrent or residual pituitary adenomas. It affords effective growth control, hormonal normalisation, and an acceptable risk of delayed endocrinopathy," concluded Dr. Sheehan.
Dr. Sheehan was presented with the Synthes Skull Base Award for this research.
[Presentation title: Gamma Knife Radiosurgery for Pituitary Adenomas: Factors Related to Radiologic and Endocrine Outcomes in a Series of 400+ Patients.]