Accuracy and Limitations of the 32P Test in the Diagnosis of Ocular Tumors: An Analysis of 500 Cases

Abstract

A study of 500 consecutive ³²P tests for suspected ocular tumors is presented. The test is 96% to 99% accurate in differentiating benign from malignant lesions of the ciliary body and choroid, but has limited value in the diagnosis of lesions of the iris and conjunctiva. It has definite limitations in its ability to differentiate choroidal melanomas from metastatic tumors to the choroid and in confirming the diagnosis of iris melanoma. Indications for the test vary from center to center, but include any suspicious lesion of the ciliary body or choroid in which the diagnosis of malignant melanoma is suspected. It should not be used on obvious metastatic tumors to the choroid, especially if there is a proved primary malignancy elsewhere in the body. The test is not particularly helpful in differentiating benign from malignant lesions of the iris and conjunctiva. Significant early and late complications of the ³²P test are rare. Although long-term follow-up information is not yet available, the isotope does not appear to be leukemogenic in the dose used for ophthalmic diagnosis.