Fractionated stereotactic radiosurgery using the Novalis system for the management of pituitary adenomas close to the optic apparatus

Radiosurgery has been proven to be an effective treatment for residual or recurrent pituitary adenomas after surgery. However, it causes severe complications when the optic apparatus is irradiated over the tolerance dose. In this study, we analyzed the feasibility of fractionated stereotactic radiosurgery to treat pituitary tumors close to the optic apparatus. Thirty-four patients from June 2006 to June 2011 with recurrent or residual pituitary adenomas close to (<3 mm) the optic apparatus were treated with fractionated stereotactic radiosurgery. Three fractions with a total dose of 2100 cGy were applied to the tumors. Imaging, examination of vision, and estimation of hormone level were regularly performed before and after radiosurgery. The mean tumor volume before fractioned stereotactic radiosurgery was 5.06 ± 3.08 cm³ (range: 0.82-12.69 cm³). After a mean follow up of 36.8 ± 15.7 months (range: 16-72 months), tumor size was reduced in seven (20.6%) patients and remained the same in the other 27 (79.4%) patients. Vision was improved in one patient and remained stable in the rest. Only one patient developed transient post-treatment diplopia. This study suggests that fractionated stereotactic radiosurgery is safe for treating pituitary adenomas close to the optic apparatus. Studies with more patients and longer follow-up are required to draw definite conclusions.