Abstract
Purpose: :
To determine the characteristics associated with local failure after palladium-103 ophthalmic plaque brachytherapy.
Methods: :
In a single center retrospective chart review of 400 consecutively treated patients, 13 (3%) were found to enlarge prompting additional therapy. Each chart was examined for patient, tumor, and plaque insertion characteristics.Outcome Measures: Preoperative factors patient age, past ocular history and presentation, intraocular pressure and visual acuity. Tumor characteristics including tumor location, height, largest diameter, shape, internal reflectivity, presence of retinal detachment and extrascleral extension. 3) Plaque size, dose to apex, distance to fovea and optic nerve. Operative factors including: 1) intraoperative ultrasonography 2) repositioning of extraocular muscles. Postoperative factors including 1) plaque related complications, 2) neovascular glaucoma 3) metastases.
Results: :
On initial presentation 9 (69%) eyes had decreased visual acuity as their predominant symptom (ranging from 20/16 to count fingers). Ultrasonography revealed 69% dome-shaped choroidal tumors, a mean apical height of 3.2 mm (range 1.9 to 6.5 mm) and median apical height of 2.7 mm. Two (15%) tumors induced an exudative retinal detachment. The largest basal tumor dimension was a mean 9.4 mm (range 6.0 to 15.5). This included (7th Edition AJCC) 38% T1, 23% T2, 31% T3, and 8% T4 tumors. No tumors had pre-operative extrascleral extension. Tumor location was posterior to the equator in 69% of tumors. All (100%) tumors were COMS medium-sized.Plaque localization was confirmed by ultrasonography in 100% of cases. Five eyes (38%) required temporary extraocular muscle repositioning. Radiation dose to apex was a mean 80.4 Gy. Postoperatively, 4 (31%) eyes developed radiation retinopathy and optic neuropathy and 1 neovascular glaucoma. The mean time to local tumor regrowth was 35.8 months. Following treatment, 100% of patients achieved a reduction in apical height. At time of failure, 5 eyes (38.5%) had apical growth, 5 eyes (38.5%) had marginal growth, 2 eyes (15%) recurred as a ring melanoma and 1 eye (8%) developed extrascleral extension. Though follow-up tumor staging was negative at the time of tumor regrowth, in total 4 (31%) patients developed metastatic melanoma.
Conclusions: :
Local treatment failure occurred in only 13 of 400 (3%) of pd-103 plaque treated patients. These were mostly medium-sized, posterior tumors; however iridociliary tumors were at risk for circumferential extension. Local failure was associated with an increased risk of metastatic melanoma.
Keywords: radiation therapy • melanoma • tumors