Overall and progression-free survival and visual and endocrine outcomes for patients with parasellar lesions treated with intensity-modulated stereotactic radiosurgery.

Linear accelerator single-fraction radiosurgery (SRS) for skull base lesions is usually delivered with dynamic conformal arcs (DCAs), but intensity-modulated radiosurgery (IMRS) is another option when SRS dose is limited by proximity of the optic nerve and chiasm. We review the long-term outcome of patients treated with IMRS for parasellar lesions. Fourteen patients with parasellar lesions were treated with IMRS when standard DCA radiosurgery was limited by optic nerve tolerance. Prospective patient data included endocrine function, visual acuity and field testing, nonoptic nerve cranial neuropathy, and overall survival. In addition, tumor control on serial magnetic resonance imaging is reported as progression-free survival (PFS). Six patients with cavernous sinus meningiomas and eight with recurrent pituitary adenomas were treated. Three of the pituitary tumors were hormonally active (two with Cushing disease, one with acromegaly). The median patient age was 50 years (range 24-70 years). Median follow-up was 54 months. Average tumor treatment volume was 4.99 ml (average dose 16 Gy, average of 10 IMRS fields). Tumor control was achieved in 11 of 14 (79%) patients. Median PFS has not been reached in our patient population. Thirteen patients are alive (one died of an unrelated cancer). No patients developed new endocrinological, ophthalmological, or cranial nerve deficits. IMRS allows for treatment of parasellar lesions when standard DCA SRS is limited by optic nerve tolerance. Although our follow-up period was relatively short and the number of patients was small, it appears that this can be accomplished with a high tumor control rate and survival without new endocrinopathies, optic neuropathies, or other complications in patients who have failed other therapies.