Microwave plaque thermoradiotherapy for choroidal melanoma

Abstract

Microwave thermoradiotherapy was used as a primary treatment for 44 patients with choroidal melanoma. An episcleral dish-shaped microwave antenna was placed beneath the tumour at the time of plaque brachytherapy. While temperatures were measured at the sclera, the tumour's apex was targeted to receive a minimum of 42 degrees C for 45 minutes. In addition, the patients received full or reduced doses of plaque radiotherapy. No patients have been lost to follow-up. Two eyes have been enucleated: one for rubeotic glaucoma, and one for uveitic glaucoma. Though six patients have died, only one death was due to metastatic choroidal melanoma (39 months after treatment). Clinical observations suggest that the addition of microwave heating to plaque radiation therapy of choroidal melanoma has been well tolerated. There has been a 97.7% local control rate (with a mean follow-up of 22.2 months). We have reduced the minimum tumour radiation dose (apex dose) to levels used for thermoradiotherapy of cutaneous melanomas (50 Gy/5000 rad). Within the range of this follow-up period no adverse effects which might preclude the use of this microwave heat delivery system for treatment of choroidal melanoma have been noted.