Objective: To evaluate size, characteristics, and regression of iris and iridociliary melanomas on high-frequency ultrasound images before and after plaque brachytherapy.
Methods: Retrospective review of high-frequency ultrasound characteristics of 24 consecutive iris and iridociliary melanomas before and after radiation therapy.
Results: The median tumor thickness before radiation therapy was 2.3 mm (range, 1.4-4.3 mm). Nineteen iris melanomas (79%) involved the ciliary body, 18 (75%) involved the iris pigment epithelium, 11 (46%) were club shaped, and 4 (17%) caused disinsertion of the iris root. At a median follow-up of 30 months after plaque brachytherapy, the mean tumor thickness had diminished to 1.2 mm (median, 1.2 mm; range, 0.9-1.9 mm). While all tumors exhibited a reduction in thickness, no tumors showed additional regression after 30 months past treatment. Fourteen tumors (58%) were noted to have increases in internal reflectivity. There was 1 failure of local control (at 6 years), successfully treated by a second application of plaque brachytherapy.
Conclusion: High-frequency ultrasonography revealed unique tumor characteristics, quantified tumor size, and demonstrated tumor response to radiation therapy.