Radiotherapy of unilateral choroidal metastasis: unilateral irradiation or bilateral irradiation for sterilization of suspected contralateral disease?

Radiotherapy is the highly effective standard in the treatment of choroidal metastasis. Visual acuity can be stabilized or increased in about 70-80% of eyes treated, thus prevailing the quality of life in these worse prognostic patients. In about 30-40% bilateral macroscopic disease is found at diagnosis. The best treatment for unilateral metastasis remains controversial: unilateral or bilateral irradiation for sterilization of suspected contralateral metastasis or unilateral irradiation without irradiation of the contralateral choroidea. In the analysis of a prospective study (ARO 95-08) 35 out of 50 patients with choroidal metastasis had unilateral disease and received unilateral irradiation with a lateral field using 6 MeV-photons (40 Gy in 20 fractions) without sparing the contralateral choroidea. Therefore the posterior contralateral choroidea received 50-70% of the total dose (20-28 Gy) for suspected micrometastasis. None of these patients developed contralateral choroidal metastasis during the median follow up time of 11.5 months. A unilateral field with 40 Gy for unilateral choroidal metastasis without sparing the contralateral choroidea seems to be effective in destroying contralateral micrometastasis with a lower risk of late side effects compared with bilateral fields.