Management of Large Choroidal Melanoma With I-125 Plaque Brachytherapy: A Case Series of 39 Patients

Abstract

Enucleation is generally advised when melanoma is >16 mm in diameter and >10 mm in thickness, as was performed in the COMS report #10 and #24. The purpose of this investigation was to report on the outcomes with regards to tumor control, globe salvage, side effects, visual acuity, and distant metastasis in patients with large choroidal melanoma treated with I-125 plaque brachytherapy. A retrospective chart review of 39 consecutive patients with choroidal melanoma diagnosed and treated with plaque brachytherapy instead of enucleation at the Ocular Oncology Service of a single institution between September 2009 and February 2011. There were 39 patients with large choroidal melanoma (diameter >16mm or height > 10mm) that were treated between September 2009 and February 2011 with plaque brachytherapy. The mean patient age was 61 years (median 64 years, range 30-93 years), and 20 (51%) were male and 19 (49%) were female. Pre-treatment visual acuity was good [20/20-20/40] in 22 patients (56%), intermediate [20/50-20/100] in 9 (23%), or poor [20/150-no light perception] in 8 patients (21%). The mean calculated dose to the apex of the tumor was 70 Gy. The mean dose to the tumor base was 225 Gy (median 201 Gy, range 88 Gy – 444 Gy). The mean dose to the foveola was 51 Gy (median 39 Gy, range 13 Gy – 150 Gy) and the mean dose to the optic disc was 43 Gy (median 35 Gy, range 9 Gy-154 Gy). There were 36 patients (92%) that received post radiation bevacizumab injections. Two patients (5%) demonstrated local recurrence. One recurrence was treated with repeat plaque radiation therapy and 1 patient (3%) required enucleation. Post treatment visual acuity was good in 4 patients (10%), intermediate in 11 patients (28%), and poor in 24 patients (62%). Post treatment melanoma thickness decreased on average by 49% (median 53%, range 3%-87%) at mean 37 months follow up. Thirty patients (77%) developed radiation maculopathy and 11 (28%) developed radiation papillopathy. There were 6 patients (15%) who developed distant metastatic disease. Over a mean follow up period of 37 months, local melanoma control rate was 95%. Globe salvage was achieved in 97% of patients, despite a large tumor. Poor visual outcome was noted in 62% of patients, as compared to 23% prior to treatment. Selected large choroidal melanoma can be treated with plaque radiation therapy with excellent local control, but poor visual outcome should be anticipated.