Bidirectional thermotherapy for choroidal melanoma

Abstract

Sir, An 81-year-old male had recurrence of choroidal melanoma after three sessions of transpupillary thermotherapy (TTT) and double freeze-thaw cryotherapy once over a 7-year period. At initial presentation in 2003, the melanoma had a thickness of 1.9 mm without scleral extension or involvement of ciliary body or optic nerve. He refused plaque brachytherapy because he was monocular since childhood after enucleation secondary to trauma. Initial treatment therefore was TTT followed by transscleral cryotherapy at 4 months later. Recurrences in 2007 and 2009, heralded by increased pigmentation at the edge of previously treated areas, were treated with repeat TTT. Visual acuity was 20/25 in 2010 at the time of the most recent recurrence (Figures 1a and b). There was no evidence of extrascleral extension or metastases. The patient again declined plaque brachytherapy because of concerns regarding vision loss. He underwent intraoperative TTT with concurrent transscleral diode laser thermotherapy (TDT). TDT was carried out using indirect ophthalmoscopy and 80-s duration exposures. The power was titrated to achieving a grey colour to the retina. No complications occurred. By the following day, a mildly grey colour was seen to the retina (Figure 1c). Figure 1 (a) Increased pigmentation at border of previous TTT for choroidal melanoma. (b) Ultrasound revealing bilobed elevation without evidence of scleral extension. (c) Postoperative photo after bidirectional thermotherapy showing grey area over treatment area. ... Extrascleral extension of melanoma cells is a leading cause of failure in TTT.1 TTT may not penetrate the depth of the melanoma completely in some cases, resulting in residual viable melanoma cells usually in the outermost scleral aspect of the mass. The addition of TDT may complement TTT in achieving necrosis of melanoma cells in the outermost portion of the melanoma or even in the infiltrating scleral portions that are undetectable by ultrasound. Cryotherapy following TTT has also been applied using this concept but has been unsuccessful.2 TDT has been shown to not disrupt scleral architecture.3, 4, 5 Bidirectional thermotherapy with TDT with TTT could result in a ‘sandwich' treatment in both the anterior-to-posterior and posterior-to-anterior directions. Our patient has unique characteristics because of his ocular history and refusal of plaque brachytherapy, therefore requiring a novel approach to choroidal melanoma treatment. Bidirectional thermotherapy may decrease the risk of extrascleral extension in selected patients with choroidal melanomas amenable to TTT.