Intraoperative echographic localization of iodine-125 episcleral plaque for brachytherapy of choroidal melanoma

PURPOSE: To report intraoperative echographic localization of iodine-125 ep iscleral plaque for brachytherapy of choroidal melanoma. METHODS: In a retrospective study, 117 eyes with medium-sized choroidal mel anoma in 117 patients not participating in the Collaborative Ocular Melanom a Study underwent iodine-125 episcleral plaque radiotherapy with intraopera tive echographic verification of plaque placement between January 1992 and December 1998 at the Bascom Palmer Eye Institute. RESULTS: After initial plaque placement using standard localization techniq ues, intraoperative echography demonstrated satisfactory tumor-plaque appos ition in 76% of eyes (89 of 117). In the 28 eyes (28 of 117, 24%) that requ ired repositioning of the plaque, the extent of misplacement was less than 1 mm in 10 eyes, 1.1 to 3.0 mm in six eyes, and greater than 3 mm in eight eyes. Two eyes had tilting of the plaque, and in two additional eyes, altho ugh the plaque covered all tumor margins, the centration was considered sub optimal. Repositioning was necessary in 1 eye with an anteriorly located tu mor (1 of 13, 7.7%) and in 20 eyes with peripapillary or posterior pole tum ors (20 of 67, 26.3%). Anteriorly located tumors required plaque reposition ing significantly less frequently than did posteriorly located tumors (P = .041). Misalignment involved one tumor margin in 23 eyes and two margins in five eyes. The most commonly misaligned margins were the lateral (35%) and posterior margins (26%). In no case was an anterior marginal misalignment documented. At a mean follow-up of 37 months, no tumor-related death or met astatic disease was noted. Two of the 117 patients (1.7%) had local tumor r ecurrence and underwent enucleation. CONCLUSIONS: Intraoperative echography is an effective adjunct for localiza tion and confirmation of tumor-plaque relationship. This technique facilita tes the identification and correction of suboptimal plaque placement at the time of surgery, potentially minimizing treatment failures. (Am J Ophthalm ol 2000;129: 199-204. (C) 2000 by Elsevier Science Inc. All rights reserved .)