LAUSR

BACKGROUND In patients with residual or recurrent non-functioning pituitary adenomas (NFPAs) following transsphenoidal resection, both GammaKnife (GKRS) and CyberKnife (CKRS) stereotactic radiosurgery (SRS) are viable treatment options. OBJECTIVES We report a retrospective single center series comparing assessing the effectiveness and complications from of these two commonly used SRS techniques. METHODS 53 patients with prior surgical resection and residual or recurrent NFPAs who underwent GKRS or CKRS and minimum 3 months follow-up between January 2002 and February 2017 at a single center were identified. RESULTS 34 patients underwent GKRS and 19 received CKRS. CKRS patients had larger maximal tumor diameter (p=0.005) and tumor volume treated (p=0.001). Differences between GKRS and CKRS treatment parameters included target volume, target volume treated, prescribed dose, maximum dose, prescription isodose line and conformity index (p<0.05). The mean follow-up time was 53.74 months for GKRS and 41.48 months for CKRS patients. Tumor progression developed in 6% of cases following GKRS versus 5% following CKRS. Mean PFS was 48.44 months following GKRS and 38.57 months following CKRS (p=0.61). Five-year actuarial tumor control rates were 91% following GKRS vs 89% following CKRS (p>0.99). There were no differences in worsened vision or rates of hypopituitarism. CONCLUSIONS For patients undergoing single fraction GKRS versus fractionated CKRS for NFPAs, both modalities had similar rates of tumor control, new hypopituitarism and visual morbidity despite varying indications. This study validates the versatile use of these two SRS modalities for patients meeting their relative criteria, especially based on proximity to the optic apparatus and normal pituitary gland.