Fractionated stereotactic radiotherapy with linear accelerator for uveal melanoma -: Preliminary Vienna results

Purpose: To study local tumor control and radiogenic side-effects after fractionated stereotactic radiotherapy for uveal melanoma. Patients and Methods: Between June 1997 and February 1998, 21 patients suffering from uveal melanomas have been treated with a stereotactic 6 MeV LINAC (Saturne 43(R), General Electric; France) in conjunction with a stereotactic frame system (BrainLAB(R), Germany). Immobilization of the eye: was ensured with an optical fixation system which was proven reliable. During radiotherapy, movements of the irradiated eye were controlled on a monitor and documented by video recording. All patients co-operated Very well with the optical fixation system. In 1164 measurements, the median value of horizontal deviation of the diseased eye during treatment was 0.3 mm (range: 0 to 1.3 mm). Median vertical deviation was 0.2 mm (range: 0 to 1.2 mm). For all patients, mean tumor prominence before treatment was 6.0 +/- 2.2 mm. In 20 patients, the total dose of 70 Gy (at 80%) was delivered in 5 fractions within 10 days. In one patient with a ciliary body tumor, the total dose of 70 Gy was divided into 7 fractions for better sparing of the anterior eye segment. Results: After a follow-up of at least 6 months, local tumor control was seen in all eyes. Mean tumor thickness reduction after 3, 6 and 9 months was 7%, 13% and 31%, respectively. Up to now, only mild subacute side-effects located in the anterior eye segment have been noticed. Conclusion: Optical fixation of the eye allows high precision stereotactic radiotherapy with small safety margins. Fractionated stereotactic radiotherapy and 70 Gy total dose delivered in 5 fractions seems to be appropriate for local tumor control in uveal melanoma. Further long-term studies with extended number of patients will be necessary to conclude on the use of linac-based fractionated stereotactic radiotherapy for uveal melanoma.