Abstract
Purpose :
The purpose of this study was to determine the efficacy of fractionated stereotactic radiosurgery (fSRS) to treat American Joint Commission of Cancer (AJCC) category T4 posterior UM.
Methods :
Non-randomized, retrospective case series of patients with T4 UM who underwent fSRS during a 9-month period (late 2015-early 2016) and were followed for 2 years. Patients were included if they presented with T4 posterior UM. Patients were excluded if treated previously, or if a plaque for brachytherapy could be placed. All patients were offered enucleation (standard of care) or fSRS. During the 9-month period, 10 patients met the inclusion criteria. 1 was excluded because of prior brachytherapy, 1 could be treated with plaque brachytherapy and 2 chose primary enucleation. Therefore, 6 patients underwent fSRS. Following contouring with orbit CT and/or MRI, fSRS was performed in 3 fractions of 10Gy/fraction. Primary outcome was tumor control at 1-year. Secondary outcomes were globe retention and absence of major vascular complications (retinal vascular occlusions or neovascular glaucoma [NVG]) at 1-year. Radiation retinopathy, imaging findings, and longer-term results were also recorded.
Results :
At 1-year, tumor control was achieved in 6/6 (100%) eyes. At 1-year, no eyes required secondary enucleation (100% globe retention) and no eyes (0%) developed vascular complications (secondary endpoints). In contrast, a previous cohort who received un-fractionated SRS all developed vascular complications by 1-year. With fractionation, by 2-years, 1 eye required secondary enucleation for persistent tumor cells in the vitreous, despite clear regression of the treated choroidal tumor mass. Thus, 2-year tumor control rate and globe retention were both 83% (5/6). However, by 2-years, 4/5 of the remaining eyes developed NVG, which was managed with drops and/or bevacizumab and/or panretinal photocoagulation. The last eye developed NVG at 26-months. Of the 5 retained eyes, 4 had presented with acuity ≥20/100, and 3 of these 4 eyes retained acuity ≥20/100 at 2 years. No metastases or deaths occurred.
Conclusions :
Excellent rates of tumor control and globe retention can be achieved with fSRS for very large CMs, with surprising retention of vision. However, eyes develop NVG by 2-years post-treatment. Sustained prophylaxis with intravitreal anti-vascular endothelial growth factor injections may be considered.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.