Fractionated Gyroscopic Radiosurgery for Optic Nerve Glioma: A Case Report and Review of the Literature.

Radiotherapy offers a favorable long-term outcome for the treatment of optic pathway glioma, but at a cost of neurocognitive impairment and decreased quality of life. This has led to a chemotherapy-first approach, deferring radiotherapy till disease progression. We present a case report wherein a 20-year-old female patient with left optic nerve glioma was treated with definitive radiotherapy using a self-shielding gyroscopic radiosurgery (GRS) system. We report the first published use of GRS in the treatment of optic nerve glioma. The patient was treated with 15 Gy at the 56% isodose line in two fractions on alternate days with 17 isocenters and 271 non-coplanar beams, amounting to a total treatment time of 63 minutes. The evaluation of the treatment plan shows considerable sparing of the normal structures, which may translate into better long-term clinical outcomes. A clinical follow-up after a month of treatment showed good clinical control without any undue treatment-related toxicity. Further follow-up is slated as per standard protocol. This case report opens up the potential for considering GRS after careful scrutiny as a first-line approach in the treatment of optic nerve glioma.