gms | German Medical Science

Beta-ray brachytherapy and proton beam irradiation are established treatment options for uveal melanoma. Until now it is unclear, which form of treatment should be preferred in an individual case with posterior uveal melanoma.

This retrospective, non-randomized matched pairs study analysed the outcome of 56 pairs of patients with uveal melanoma treated either with proton-beam irradiation or ruthenium-brachytherapy. The patients were matched for age and tumour location (64.3% juxtapapillary) with a mean tumour height of 4.2 mm (range 1.1 - 7,3 mm). The initial corrected visual acuity was 0,6 in both groups. The same surgeons performed the brachytherapy between 1981 and 1996 in academic centers in Berlin and Essen. Proton beam treatment was performed at Centre Lacassagne, Cyclotron Biomedical in Nice, in all cases. Study parameters were survival, tumour control rate, radiotherapy induced complications and visual acuity after treatment.

Median follow-up was 26 months in the proton beam group and 35.3 months in the brachytherapy group. Tumour related death occurred in one case (1.8%) in both treatment groups. Additional treatment of the tumour was indicated in one case after brachytherapy and in 5 cases after proton beam irradiation (p=0.003). Both treatment groups showed absolute tumour control and eye-preservation in 98.2%. Radiotherapy induced vascular complications occurred after 1 and 3 years in 25,7% and 62,3% of eyes after brachytherapy and in 62,3% and 74,6% of eyes, respectively, after proton beam irradiation (p=0,68). Three years after brachytherapy 5,8% of eyes showed cataracts. The corresponding rate for proton beam treated eyes was 24.4% (p=0.06). A loss of reading ability (acuity < 0.4) assessed 6 months after treatment orrurred in 74.5% of eyes after brachytherapy and in 35.7 % of eyes after proton beam treatment (p=0.002). The latter patients developed further loss of visual acuity during follow-up. Three years after treatment final visual acuity was similar in both groups (p>0.05). At this time, 19.8% and 22.8% of the treated eyes were functionally blind after brachytherapy or protontherapy, respectively (p=0.7).

This retrospective study showed no clinically relevant differences between the outcome of brachytherapy or proton therapy in the treatment of posterior uveal melanoma regarding the mortality, the tumour control rate or radiotherapy induced vascular complications. The most important difference was the significantly slower loss of visual acuity in the treated eye after proton beam irradiation. Three years after the end of treatment both groups showed a similar mean visual acuity. Quality of life, associated with better vision, is maintained for a longer period after proton therapy.