Outcomes of Medium Choroidal Melanomas Treated with Eye-Physics Ruthenium Plaque Brachytherapy

Abstract

 

Purpose

 

The Collaborative Ocular Melanoma Study (COMS) established Iodine 125 plaque brachytherapy as the standard eye preservation treatment for medium sized choroidal melanomas in the United States. Plaque Simulator (PS) software guided treatment utilizing Eye Physics (EP) plaques provides optimal treatment by enabling customizable radiation profiles for a variety of tumor shapes and sizes. Berry et. al. recently reported EP customized Iodine-125 therapy with similar results to the COMS Iodine-125 non-custom plaques. Herein we report results from a series of 15 patients treated with EP custom Ruthenium Plaque Brachytherapy.

 

Methods

 

Fifteen patients with medium sized choroidal melanomas (2.84-5.5 mm in apical height and a basal diameter of 7.8-12.6mm) treated with ruthenium-based brachytherapy from 2003-2005 were evaluated in a retrospective chart review. Baseline and follow-up data were collected and evaluated for: tumor height, best corrected visual acuity, radiation retinopathy, radiation optic neuropathy, post-radiation cataract formation, diplopia and ptosis. Tumor response kinetics for EP ruthenium plaques, EP iodine plaques were evaluated and compared.

 

Results

 

Incidences of adverse radiation effects were documented: optic neuropathy (6.7%), retinopathy (20%), and cataracts (33%) (Table). Tumor height after therapy demonstrated regression profiles equivalent to tumors treated with Iodine-125 plaques. Five year tumor heights for radiation treated tumors were approximately 0.61 +/- 0.29 (iodine, n=16) and 0.53 +/- 0.17 (ruthenium, n= 6) relative to their heights at diagnosis (Figure).

 

Conclusions

 

This patient subset had background characteristics very similar to those from the COMS and patients treated with EP iodine-125 plaques. Treatment response was equivalent and radiation complications occurred slightly less frequently than those patients treated with iodine-125 radiation. Tumors treated with EP brachytherapy shrink to about 50-60% of their initial height at diagnosis. EP plaque brachytherapy demonstrates similar results with COMS plaques regardless of radiation source.

 

 

Table: a. Baseline characteristics of patients b. Tumor response and clinical outcomes.

 

 

Figure: Tumor response to plaque brachytherapy with Iodine (blue) and Ruthenium (Green). The subgroup of patients who were treated with Iodine and developed metastasis are plotted in Red.

 

Keywords: 589 melanoma • 671 radiation therapy • 670 radiation damage: light/UV