RADIATION RELATED COMPLICATIONS AFTER RUTHENIUM PLAQUE RADIOTHERAPY OF UVEAL MELANOMA

Aims/background - To analyse radiation related complications and secon dary enucleation after irradiation of malignant uveal melanoma with ru thenium-106 plaques. Methods - A series of 100 consecutive eyes irradi ated in 1981-91 was analysed using the life table method and the Cox p roportional hazards model. The median apical and scleral tumour dose w as 100 Gy (range 15-200 Gy) and 1000 Gy (range 200-1200 Gy), respectiv ely, The median follow up time was 2.8 and 2.0 years (range 1 month to 10 years) for anterior and posterior segment complications, respectiv ely, Results - The 3 and 5 year probabilities of being without radiati on cataract were 73% and 63%, without neovascular glaucoma 91% and 81% , without vitreous haemorrhage 83% and 74%, without radiation maculopa thy 85% and 70%, and without radiation optic neuropathy 90% and 88%, r espectively. The risk of radiation cataract was highest with large tum our size (T1+T2 v T3, p=0.0027; height less than or equal to 5 v >5 mm , P=0.029; largest basal diameter (LED) less than or equal to 15 v >15 mm, p<0,0001) and location of anterior tumour margin anterior v poste rior to the equator (p=0,0003); the risk of neovascular glaucoma with large size (T1+T2 v T3, p=0,039; LBD less than or equal to 15 mm v 15 mm, p=0,021); and the risk of maculopathy and optic neuropathy with pr oximity of the posterior tumour margin to the fovea and the optic disc (less than or equal to 1.5 v >1.5 mm; p=0,030 and p=0,0004, respectiv ely), In Cox's multivariate analysis the strongest risk indicator for radiation cataract (RR 1.5, 95% CI 1.4-1.6) and vitreous haemorrhage ( RR 1.6, 95% CI 1,4-1.8) was the height of the armour; for neovascular glaucoma the TNM class (RR 6.2, 95% CI 2.7-13.8); for radiation maculo pathy location of posterior tumour margin within 2 mm from the fovea ( RR 3.4, 95% CI 2.0-6.0); and for radiation optic neuropathy location o f tumour margin within 1 DD of the optic disc (RR 6.1, 95% CI 3.0-12,4 ). The 3 and 5 year probabilities of avoiding enucleation were 92% and 85%, respectively, Ten eyes were enucleated - six because of recurren t tumour growth, three because of treatment: complications, and one be cause of mistakenly suspected extraocular growth. Conclusion - The res ults suggest that the frequency of radiation related complications aft er ruthenium brachytherapy of uveal melanoma is acceptable, in particu lar as regard irradiation of small and medium sized tumours for which ruthenium therapy generally is recommended.