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

To study local tumor control and radiogenic side-effects after fractionated stereotactic radiotherapy for uveal melanoma.

Between June 1997 and February 1998, 21 patients suffering from uveal melanomas have been treated with stereotactic 6 MeV LINAC (Saturne 43, General Electric, France) in conjunction with a stereotactic frame system (BrainLAB, 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.

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.

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.