Purpose
To review the University of Southern California (USC)/Doheny Eye Institute experience using Eye Physics® (EP) plaques and Plaque Simulator™ (PS) software to treat medium-sized choroidal melanomas and to compare the outcomes with results from the Collaborative Ocular Melanoma Study (COMS).
Methods
A retrospective case series of 82 patients treated for choroidal melanoma from 1990 to 2010 using plaques and treatment simulation software developed at USC. The dosimetric goal was to deliver 85 Gy to a conformal volume enclosing the tumor apex and a 2 mm margin surrounding the base. Plaque localization was guided by PS computer modeling system using preoperative imaging studies. Primary outcome measures were local tumor control, globe preservation, and metastases. Secondary outcome measures were late radiation side effects, including vision changes, optic neuropathy, radiation retinopathy, and cataract.
Results
Median follow-up for 82 patients was 46.8 months (range, 1-171 months). Globe preservation was achieved in 80 (97.5%) patients; two patients underwent enucleation for local recurrence. Metastatic disease developed in 9 (10.9%) patients during the follow-up period. Retinopathy was seen in 31 (37.8%), optic neuropathy in 12 (14.6%) and cataracts in 26 (31.7%) patients. Postoperatively, 21 (25.6%) patients lost >6 lines of Snellen visual acuity.
Conclusions
When considering rates of local recurrence, metastases, and late radiation side effects, the results of treating medium-sized choroidal melanomas with EP plaques compare favorably with the COMS data. The PS three-dimensional tumor modeling program developed at USC is a reliable method for determining plaque positioning preoperatively and for treating this cohort of patients.