Preliminary results of proton radiotherapy for choroidal melanoma – the Kraków experience

Aim of the study: The objective of the study was to present the preliminary results of proton radiotherapy as a method for treating 15 patients with choroidal melanoma.

Material and methods: The proton radiotherapy was administered using beams providing energy levels of 60 MeV, which ensures a clinical range of 28.4 mm. In addition, the beam has a very narrow penumbra of 1.3 mm and a sharp distal dose fall-off. All patients received the dose of 60 CGE (cobalt gray equivalent) given to the PTV (planning target volume). This dose was administered in 4 fractions over 4 successive days of treatment.

Results: The tumour had regressed in 8 patients (53.3%) and remained stable in 3 patients (20%). The large tumours in another 3 patients (20%) were removed during vitrectomy (endoresection), which increased the number of patients with tumour regression up to 11 (73.3%). In the case of 1 patient, despite intraocular tumour regression occurring the choroidal melanoma had spread multifocally into the orbit, which necessitated orbit exenteration. The results ensured that the eyeballs of 14 patients (93.3%) could be saved.

The follow-up period for the 15 patients ranged between 8 and 26 months (average: 17.4 months, median: 19 months). In this period some side effects were noted: an increase in intraocular pressure, retinal detachment, cataract, maculopathy, neuropathy and vitreous haemorrhaging.

Conclusions: The preliminary results confirm that proton radiotherapy is an effective method for treating patients with choroidal melanoma. This method ensures an eyeball preservation rate of 93%, with the vision function of 80% of the patients being saved.