Microwave plaque thermoradiotherapy for choroidal melanoma.

Abstract

Microwave thermoradiotherapy was used as a primary treatment for 44 patients with choroidal melanoma. An episcleral dishshaped 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°C for 45 minutes. In addition, the patients received full or reduced doses of plaque radiotherapy. No patients have been lost to foliow-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 weli 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 foliow-up period no adverse effects which might preclude the use of this microwave heat delivery system for treatment of choroidal melanoma have been noted.

Episcleral plaque 125I radiotherapy with episcleral LCF hyperthermia: A prospective randomized trial

“…There was also an expectation that a reduced radiation dose in patients receiving episcleral thermoradiotherapy may decrease the incidence of treatment complications (4,12,17,18). It has been shown that a reduction of the episcleral radiation dose, if used concurrently with HT, can account for cessation of tumor growth or shrinkage in up to 90% of cases (4,12,17). Decreased incidence of treatment complications in these patients has also been reported (4,12,17).…”

“…These findings provided a rationale to reduce the radiation dose for patients who receive EPRT in addition to episcleral HT. There was also an expectation that a reduced radiation dose in patients receiving episcleral thermoradiotherapy may decrease the incidence of treatment complications (4,12,17,18). It has been shown that a reduction of the episcleral radiation dose, if used concurrently with HT, can account for cessation of tumor growth or shrinkage in up to 90% of cases (4,12,17).…”

Current Conservative Management Strategies for Uveal Melanoma

“…The ultimate goal will be to use the sensitizing effect of radiation as well as the primary cytocidal effects of hyperthermia in order to expect a more efficient form of tumor destruction in choroidal melanomas [85]. There are some Phase I/II clinical trials addressing this question [83,84,86].…”

“…Hyperthermic treatment consists of scleral temperatures of 42-52°C for a period of 45 min once per patient. Preliminary results indicate that lowering the total radiation dose and additional heat may have the same local control as full-dose radiation treatment [83], but the two major groups [83][84][85] declare thermoradiotherapy for intraocular tumors as empirical and experimental treatment, with clinical indications being in the beginning. This is mainly due to inadequacies of hyperthermia technology in this very special clinical approach.…”

“…Thermoradiotherapy Hyperthermia is known to potentiate the tumoricidal effects of radiation. The approach to treat uveal (choroidal) melanomas with hyperthermia is based on three factors [83]: 1. Choroidal melanomas are relatively small in most of the cases and well accessible for contact applicators; 2. with a microwave plaque, the heat resistant sclera is the only normal structure between the plaque and the tumor; 3. transscleral treatment ensures that the tumor's vascular supply will be treated with up to the highest temperatures.…”