Analysis of local recurrence causes in uveal melanoma patients treated with 125I brachytherapy – a single institution study

Purpose
To perform a retrospective analysis of factors which might affect the occurrence of a relapse of uveal melanoma after ¹²⁵I brachytherapy.

Material and methods
The analysis concerned 343 patients treated in the years 2001-2012. The effect on local recurrence of such factors as patient’s sex, age, tumour size, shape, pigmentation, location, presence of orange pigment or petechiae on tumour surface, retinal detachment, and blood or dispersed pigment in vitreous body were studied. Additional analysis concerned physical properties of brachytherapy (total dose, irradiation dose applied to tumour apex and base and irradiation time). Two groups of patients were distinguished: with and without a relapse. The diagnostic criterion for the relapse was growth of the tumour base or height by 0.5 mm.

Results
Local recurrence of the uveal melanoma was observed in 29 patients (8.5%). Recurrences occurred with significantly higher frequency (p < 0.001), when the anterior tumour edge involved the ciliary body. Patients’ survival in relation to the moment the occurrence of the relapse was statistically significant for application time (p = 0.004) and tumour pigmentation (p = 0.010). The deaths of patients with a local relapse were most rare when brachytherapy lasted from 72 to 95.9 hours and most frequent in cases of brownish tumour pigmentation. Patient sex, tumour shape and size, presence of orange pigment, retinal detachment, petechiae and bleeding to vitreous body as well as the dose of irradiation to tumour top and base did not have any significant effect on relapse occurrence.

Conclusions
Treatment of uveal melanomas with ¹²⁵I applicators allows for a high rate of positive local results. Nonetheless, the recurrence probability always exists. The involvement of the ciliary body could influence this. The survival depending on the time of relapse could be statistically significant for application time and dark-brown tumour pigmentation.