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A. D. Singh, J. F. Bena, L. Janku, A. P. Schachat; Feasibility of Prompt vs Deferred Treatment of Choroidal Indeterminate Melanocytic Lesions : A Multi Center Randomized Trial. Invest. Ophthalmol. Vis. Sci. 2007;48(13):4794.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate feasibility of a multi center randomized trial of prompt vs deferred treatment of indeterminate choroidal melanocytic lesions.
For the purpose of the trial we have classified small melanomas of the Collaborative Ocular Melanoma Study (largest basal diameter 5.0 -16.0 mm and height 1.0-3.0 mm) as "indeterminate choroidal melanocytic lesions." Only cases that exhibit one of three risk factors predictive of growth (thickness 2 mm or more, orange pigmentation, and sub retinal fluid) will be randomized 1:1 into the two treatment groups. Previous treatment (including observation for more than 6 months for stability), ciliary body involvement (50% or more), optic disc involvement (more than 180 degrees), and extrascleral extension are some of the exclusion criteria. Treatment arms include prompt treatment (within 4 weeks of evaluation at a participating center) and deferred treatment (planned observation for growth prior to treatment). "Growth" is defined as an increase in basal diameter 0.5 mm or height of at least 0.3 mm. Plaque radiotherapy (Ruthenium-106 or Iodine-125) or proton beam radiotherapy will be acceptable methods of treatment. Minimum follow up of 5 years is required. The primary aim of this trial is to evaluate the impact of prompt treatment on the risk of metastasis in indeterminate choroidal melanocytic lesions. All analyses were performed using the Power procedure in SAS software (version 9.1; Cary, NC). Melanoma-specific mortality was assumed to be 1% for small tumors and 10% for medium tumors at 5 years. The drop-out was assumed to be 15% at 5 years and follow an exponential distribution. A log-rank test with a significance level of 5% and power of 80% was assumed for all calculations.
There will be sufficient power to detect an increase in mortality from 1% to 5% with 338 patients and 1% to 10% with 120 patients. Because of stringent inclusion criteria in this study, patients may be more susceptible to growth (and death) the 1% mortality rate among the treated patients may be an underestimate. If the mortality rate is 5%, then 528 patients would be required to detect an increase in mortality to 10%.
Despite enrolling a large number of patients no treatment benefit may be detected. However, even a "negative" outcome from this trial would be informative, because it would indicate lack of beneficial effects of prompt treatment. In addition, the results of this trial should provide robust data that will act as a stimulus for future investigations.
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