Gamma Knife surgery in the management of orbital tumors

Abstract

Object The authors evaluated the results they obtained using Gamma Knife surgery (GKS) in patients with orbital tumors. Methods This is a retrospective clinical evaluation of 202 patients with orbital tumors who were treated with GKS between September 1995 and October 2008. The series included 84 men and 118 women with a mean age of 39.5 ± 14.6 years (range 5–85 years). The diagnoses were determined based on pathological analyses in 113 patients and presumed based on characteristic clinical and imaging findings in 89 patients. There were 84 meningiomas, 38 epithelial tumors of the lacrimal gland, 23 schwannomas, 18 malignant choroidal melanomas, 12 optic nerve gliomas, 11 orbital metastases, 10 pseudotumors of the orbit, 3 retinoblastomas, and 3 cases of fibromatosis. The median target volume was 5.4 cm3 (range 0.04–35.6 cm3). The tumor margin dose ranged from 10 to 40 Gy. Results At a median follow-up period of 34.5 ± 14.7 months (range 12–114 months), tumor shrinkage was observed in 118 patients (58.4%) and stable tumor size in 71 patients (35.1%). Regularly scheduled neuroimaging studies demonstrated evidence of tumor progression in only 13 patients (6.4%): 9 of these patients underwent repeated GKS and 4 received surgical treatment. Visual acuity was preserved in 129 patients. Seventy-two patients experienced some degree of improvement in vision. Severe deterioration of visual acuity was found in 18 of 147 patients who had useful vision before treatment. Nineteen patients (9.4%) experienced transient conjunctival edema; no other serious acute side effect was observed. Conclusions Gamma Knife surgery provides an effective management strategy in patients with orbital tumors; it achieves excellent preservation of neurological function and is associated with few treatment-related complications.

Optic nerve glioma treatment with fractionated stereotactic radiotherapy

“…In the Xu et al study, 22 202 patients with orbital tumors underwent Gamma Knife surgery. While the tumor was smaller in 58.4% of patients, it remained stable in 35.1%.…”

“…5,8,16 Few studies have shown the effectiveness of stereotactic Gamma Knife surgery for ONG, and these have a limited number of patients. 16,17,22 To our knowledge, there is only 1 case study documenting neovascular glaucoma after FSRT using the CyberKnife. 14 Thus, in the present study we revealed the clinical findings and effect of FSRT via the CyberKnife on visual acuity and local control in a child with an ONG.…”

Multisession Gamma Knife surgery for benign orbital tumors

“…Lesions developing in the orbital region often have pathological characteristics similar to those of intracranial tumors, and their biological responses to single high-dose irradiation are predicted to be similar as well, although there are few reports concerning the application of radiosurgery to orbital lesions. 1,8,11,19 However, there is an important difference between orbital and intracranial tumors with respect to radiosurgery. In the treatment of orbital tumors, radiation-sensitive structures such as the optic apparatus are inevitably exposed to substantial irradiation in almost all cases, and this may be a major reason for the undervaluation of radiosurgery.…”

Teletherapy: Advanced Techniques

“…GammaKnife stereotactic radiosurgery has been used in the treatment of ophthalmic malignancies including uveal melanoma, orbital paraganglioma, choroidal hemangiomas, cranial nerve schwannomas, and choroidal metastases [30,[33][34][35][36][37][38]. The effectiveness and adverse reactions are considered comparable between GammaKnife stereotactic radiosurgery, though dosimetric data suggests protons may confer a slightly decreased risk of second malignancies than photons when life expectancy is many decades [39][40][41][42].…”