Combined plaque radiotherapy and transpupillary thermotherapy in choroidal melanoma: 5 years' experience

Abstract

Aim: To evaluate the results of combined plaque radiotherapy and transpupillary thermotherapy (TTT) in 50 consecutive patients 5 years after treatment. Methods: 50 adult patients with choroidal melanoma were treated with ruthenium-106 (106Ru) plaque radiotherapy combined with TTT. A flat scar was the preferred end point of treatment. The mean tumour thickness was 3. 9 mm (range 1.5-8.0 mm), the mean tumour diameter was 11.3 mm (range 5.8-15.0 mm). TTT was performed with an infrared diode laser at 810 nm, a beam diameter of 2-3 mm, and 1 minute exposures. Tumours >5 mm thick received an episcleral contact dose of 800 Gy 106Ru; tumours ≤5 mm thick received a contact dose of 600 Gy 106Ru. TTT was repeated in case of incomplete tumour regression after combined therapy. Results: Complete tumour regression was obtained in 45 patients. It required one, two, or three TTT sessions in 32, 11, and two patients, respectively. In tumours ≤3 mm thick complete flattening was achieved significantly faster than in tumours >3 mm thick (log rank test p = 0.01 ). Eight melanomas were amelanotic, seven of which required multiple TTT sessions. In one patient the tumour recurred at the central margin of the treated area; this eye was enucleated. In one patient the tumour failed to regress 6 months after treatment and enucleation was performed at the patient's request. Three eyes developed severe proliferative retinopathy. Radiation maculopathy caused a loss of the best corrected visual acuity: before treatment 31 patients had a best corrected visual acuity of 20/60 or better but in only 12 patients did it remain in this range 5 years after treatment. Three patients developed distant metastasis to the liver. Conclusion: The 5 year results for combined plaque radiotherapy and TTT as treatment for choroidal melanoma are favourable in terms of complete tumour regression and low rate of recurrences; however, there was considerable loss of visual acuity as a result of radiation maculopathy.