Purpose:
To examine how tumor location affects ocular morbidity after ophthalmic plaque radiotherapy with Pd-103 for uveal melanoma.
Methods:
384 eyes were irradiated and followed for a mean 47.2 months. There were 122 uveal melanomas anterior to the equator and 233 melanomas posterior to the equator. 29 eyes were excluded from the study due to location at the equator. Anterior and posterior tumors had similar largest basal dimensions and subsequent mean plaque size (at 16 and 15.5 mm, respectively) as well as similar AJCC-UICC tumor staging. The mean apical dose for all tumors was 71.2 Gy. The mean lens dose was 25.71 Gy for anterior tumors and 7.31 Gy, for posterior tumors.
Results:
Only 18 (15%) of the patients plaqued for an anterior uveal melanoma developed secondary retinopathy. In contrast, 130 (56%) of the posterior choroidal melanoma patients developed retinopathy (p value <0.001). The odds ratio for retinopathy was 0.137 if the tumor was located anteriorly. Cataract developed in 43 (39%) phakic eyes with anterior tumors compared with 32 (15%) eyes with posterior tumors (p value <0.001). Patients with a history of cataract extraction (n=34) prior to radiation therapy were eliminated from the cataract analysis. The odds ratio for a cataract was 3.666 if the tumor was located anteriorly.
Conclusions:
While plaque radiation of anterior melanomas is more likely to cause reversible vision loss secondary to cataract, treatment of posterior tumors is more likely to be associated with radiation retinopathy, maculopathy and irreversible loss of vision.
Keywords: radiation therapy • tumors • uvea