Radiotherapy of choroidal metastases

This retrospective study was undertaken to clarify the role of high energy external beam radiation therapy (EBRT) and to determine its safety and efficacy on local control and visual acuity in patients suffering from choroidal metastases (CM).

The records of 58 consecutive patients treated with EBRT between 1970 and 1993 were analyzed. The female to male ratio was 2.9 and the median age was 59 years (range 40-81 years). Thirty-six patients (62%) had unilateral CM and 22 patients had bilateral CM. The mean number of lesions per eye was two. Retinal detachment was present in 65% of cases. The primary tumour (PT) was breast carcinoma for 38 patients (75%), lung carcinoma for 10 patients (17%) and gastrointestinal, genitourinary or unknown PT for the remaining 10 patients. The median interval of time between the PT and the CM was 55 months (range 0-228 months). All patients were treated with megavoltage irradiation. The median prescribed dose was 35.5 Gy (range 20-53 Gy) normalized at a 2 Gy per fraction schedule with an alpha/beta value of 10 Gy. Various techniques were used and whenever possible the lens was spared. Ten patients with unilateral disease were treated in both eyes.

The tumour response was slow. When assessed after 3 months or more, the complete response rate was 53% with significantly better results for doses higher than 35.5 Gy (72 versus 33%; P = 0.009). Visual acuity was improved or stabilized in 62% of patients, with also significantly better results when doses higher than 35.5 Gy (P = 0.014) were administered. Amongst 26 patients with unilateral CM who had no elective contralateral irradiation, three developed metastasis in the opposite eye versus none of the 10 patients who had bilateral irradiation. Five complications occurred (three cataracts, one retinopathy and one glaucoma).

Radiation therapy is an efficient and safe palliative treatment for choroidal metastases and it helps the preservation of vision. Thus, there is a major impact on the quality of life in a group of patients with an almost uniformly fatal prognosis. Both tumour response and visual acuity are significantly improved if doses higher than 35.5 Gy are administered. Whenever possible, a lens sparing technique should be used.