Primary transpupillary thermotherapy (TTT) for malignant choroidal melanoma

To evaluate the efficacy of transpupillary thermotherapy (TTT) as the only method of treatment for small choroidal melanoma.

In a prospective non-randomized analysis, 20 patients with primary choroidal melanoma (posterior to the equator with base < or = 2 and thickness < or = 4.5 mm) were treated with TTT as the only method of treatment (diode laser at 810 nm, beam diameter 3 mm, power setting 0.3-0.9 W, exposure time 20-37 min). During follow-up of at least 6 months, clinical aspects, ultrasonographic tumour thickness, fluorescein and indocyanine green angiographic patterns, visual acuity and ocular side-effects were recorded.

In 17 eyes the tumour regressed significantly within 3 months after one treatment session (to a flat chorioretinal scar in 15 eyes). Despite a clinically flattened chorioretinal scar, fluorescein and indocyanine green angiography revealed that choriocapillary vessels in the heat-treated areas of 15 eyes remained perfused. Three amelanotic melanomas showed almost no response to TTT after repeated treatment at higher power settings. Visual acuity remained unchanged or improved in 12 eyes. Ocular side-effects included posterior synechia of the iris (1), macular oedema (2) and temporary retrobulbar pain (2). No patient showed tumour recurrence or metastases during follow-up.

Preliminary results obtained by this study demonstrate good efficacy and visual outcome following TTT as the only method of treatment for small choroidal melanoma. However, indocyanine green angiographic findings suggest that tissue damage in the choroidal layer might be less effective, which perhaps may lead to a higher rate of tumour regrowth. Long-term follow-up is required to obtain data on late ocular side-effects, tumour recurrence and metastasis.