MICROWAVE THERMORADIOTHERAPY FOR INTRAOCULAR MELANOMA

We evaluated the use of microwave hyperthermia as an adjuvant to ophth almic plaque radiotherapy for patients with intraocular tumors. Forty- eight patients were offered combined microwave plaque thermoradiothera py (TRT) as a primary treatment for their uveal melanomas. A dish-shap ed microwave antenna was placed on the sclera beneath the tumor at the time of plaque brachytherapy. While temperatures were measured at the sclera, the tumor's apex was targeted to receive a minimum of 42 degr ees C for a 45-min duration. Patients were also given full or reduced doses of plaque radiotherapy (I-125 or Pd-103). We reduced the minimum tumor radiation dose (apex dose) for 42 (88%) of our patients to <70 Gy (mean, 52.5 Gy). The 48 TRT patients were followed for less than or equal to 8 years (average, 45 months). To date, there has been one do cumented postoperative tumor enlargement, for a 97.2% local control ra te. Two patients were lost to follow-up. Four eyes have been enucleate d: two due to neovascular glaucoma, one to glaucoma secondary to intra ocular inflammation, and one for progressive tumor enlargement. Althou gh 13 patients have died, only four deaths were due to metastatic mela noma. Thirty-five patients (73%) have maintained within two lines or h ad better than their preoperative visual acuity. Side effects attribut able to heating included chorioretinal scar formation within and aroun d the targeted zone and decreased intraocular pressures without hypoto ny. Our experience with this heat delivery system suggests that adjuva nt microwave thermotherapy can be used with plaque radiotherapy for th e treatment of uveal melanoma.