Stereotactic radiation therapy for malignant choroidal tumors - Preliminary, short-term results

Purpose: To evaluate the role of stereotactic radiation therapy (SRT) in th e treatment of malignant choroidal tumors. Design: Prospective, noncomparative case series. Participants: Ten patients with unifocal choroidal metastasis (three lung c arcinoma, three breast carcinoma, three colon carcinoma, one cutaneous mela noma) and five patients with primary choroidal melanoma underwent single-do se or fractionated SRT. Methods: Before treatment, computed tomography (CT) scans of the orbit were obtained with the patient wearing an individualized immobilization mask. A n integrated macro-CCD-camera system viewed the eye for detection of moveme nts. Three-dimensional computer-based treatment planning was carried out, D ose distribution was calculated and displayed in isodose lines on the CT da ta set, For SRT, a dedicated stereotactic linear accelerator (6 MV) was use d. Total doses for choroidal metastases were 12 to 20 Gy in a single dose o r 30 Gy over 10 days (3 Gy each session), and total doses for choroidal mel anoma were 50 Gy over 5 or 10 days (10 or 5 Gy each session). Main Outcome Measures: Best corrected visual acuity (ETDRS-chart), biomicro scopy, ultrasound examination, fluorescein angiography, and magnetic resona nce imaging (MRI) were performed before treatment and at regular intervals after completion of SRT. Results: During a follow-up period from 1 to 34 months (median, 6.5 months) , local tumor control was achieved in all eyes. A decrease in tumor size on ultrasonography or MRI was noted in eight patients. No persistent side eff ects were observed during follow-up. Conclusions: Stereotactic radiation therapy allows steep dose gradients out side the target volume by minimizing the field of exposure. Thus only low r adiation doses affect surrounding radiosensitive ocular structures. Our ini tial findings suggest that this technique may be effective in controlling t umor growth. Further studies are needed to compare treatment efficacy and s afety with conventional treatment methods. (C) 2000 by the American Academy of Ophthalmology.