Transpupillary Thermotherapy

Transpupillary thermotherapy (TTT) directs an infrared laser, usually at a wavelength of 810 nm, through a dilated pupil in one or more sessions to induce heat necrosis of uveal melanomas. This method carries the theoretical advantage of high-precision destruction of tumor tissue under direct visualization. However, TTT has important limitations that confine its use to specific circumstances.[1,29] The limited ability of TTT to penetrate thick tumors with sufficient energy restricts its use to small melanomas or tumors of a size that some ophthalmologists recommend for follow-up without any initial therapy. For more information, see the Observation section. When used as the primary therapy, there are relatively high rates of local recurrence and retinal vascular damage. Recurrence rates are particularly high when the tumor abuts the optic nerve and overhangs the optic disc.[1][Level of evidence C3]

In a single-center study, 95 patients with small choroidal melanomas (diameter <10 mm and thickness <3.5 mm) were randomly assigned to receive either TTT or 125I brachytherapy (100 Gy).[30] The tumor regression rate was 92% in the TTT arm and 98% in the 125I arm (P = .4). With a mean follow-up time of 56.2 months, there were four recurrences in the TTT arm and one in the 125I arm. However, the study was too small to provide clear information on efficacy differences.

TTT is also under evaluation as an adjunct to primary therapy with proton-beam radiation. In large uveal melanomas, proton-beam therapy is associated with exudative, inflammatory, and glaucomatous complications that may require enucleation. In a single-center trial, 151 patients with uveal melanomas at least 7 mm thick or at least 15 mm in diameter were randomly assigned to receive proton-beam radiation (60 CGEs over four daily fractions) with or without TTT (810 nm wavelength at 1, 6, and 12 months after therapy) and followed for a median of 38 months.[31] There were no differences between the two groups in maculopathy, papillopathy, or glaucoma. The enucleation rate was lower in the TTT group (about 2% vs. 18% at 5 years, P = .02). However, the study was not masked, and replication of the results would be important.

There are uncertainties at all stages about the optimal management of intraocular melanoma. Physicians should discuss clinical trial opportunities with eligible patients. Information about ongoing clinical trials is available from the NCI website.