Experience using frameless fractionated radiosurgery for the treatment of orbital and ocular tumors

Abstract

Objective This study analyzes patients with orbital tumors who were treated with fractionated stereotactic radiosurgery to help maximize local control after surgery, or to more expeditiously treat radiosensitive tumors and palliative cases. Materials and methods Thirty-one patients with tumors of the eye, orbit, or eyelid were treated using CyberKnife radiosurgery from June 2006 to June 2009. The 23 patients with at least 12 months of follow-up are included in this analysis. All patients had aquaplast mask immobilization with bolus if necessary. CT and MRI images were acquired and fused for treatment planning. Tumor contour and treatment planning was jointly performed by a radiation oncologist, ocular oncologist, and medical physicist. Total doses were lower for radiosensitive tumors (13.5-20 Gy in four to five fractions) than non-radiosensitive tumors (15-35 Gy in three to five fractions). Each fraction was delivered in 30-60 min with all treatments being delivered over 1-2 weeks. Patient ages ranged from 16 to 91 years old with a median age of 67. The majority (21 of 23) were treated with curative intent, including 9 radiosensitive tumors (all lymphomas), 17 with intact eye following limited surgery, and 3 after exenteration. Palliative patients included one metastasis and one lymphoma. Results At a median overall follow-up of 34 months (range, 13-42 months), 21 patients (91%) exhibited local control. Complications included neovascular glaucoma (n=3), chronic dry eye (n=1), and osteomyelitis (n=1). Conclusion Fractionated radiosurgery provided good local control with a low risk of side effects. Ocular oncology participation in target and normal tissue delineation was felt to be an important component of the treatment planning process.

Orthovoltage X-ray Minibeam Radiation Therapy for the Treatment of Ocular Tumours—An In Silico Evaluation

“…As the irradiation was performed through the skin and skull, one might argue that the high peak doses in the skull were also well tolerated (although a caveat may be that the PVDR in the skull was likely higher in the animal studies as a result of the shallower depths). Moreover, in an article on fractionated radiosurgery for orbital and ocular tumours [31], Morales et al present examples of treatment plans with dose depositions surpassing 40% in sizeable portions of the brain and skull. These dose distributions were furthermore laterally homogeneous, whereas a notable modulation of the dose (PVDR > 2) was maintained in the minibeam examples, which could improve tissue tolerance.…”