Clinical outcomes and secondary glaucoma after gamma-knife radiosurgery and Ruthenium-106 brachytherapy for uveal melanoma: a single institution experience

We retrospectively analyzed data from records of 48 patients (48 eyes) treated with gamma-knife (n = 18) or Ruthenium-106 brachytherapy (n = 30) for uveal melanoma, in our Ocular Oncology Unit between December 2013 and September 2019, with the aim to evaluate treatment outcomes, and incidence and risk factors for secondary glaucoma. Patients demographics and tumor characteristics at diagnosis were recorded. Follow-up data were collected regarding local tumor control, treatment complications, enucleation need, metastases occurrence and survival status. The median follow-up period was 33.7 months in the gamma-knife group and 26.2 months in the brachytherapy group. The mean tumor thickness, the largest basal diameter and the tumor volume were significantly higher in the gamma-knife group than in the brachytherapy group. The local tumor control rate was 100% in the brachytherapy group and 77.8% in the gamma-knife group. In the gamma-knife group, six patients were enucleated, no patient treated with brachytherapy underwent enucleation. The overall survival rate was 96.7% in the brachytherapy group and 94.44% in the gamma-knife group. Secondary glaucoma occurred in 10 patients after gamma-knife and in one patient after brachytherapy: it should be emphasized that larger lesions were treated with gamma-knife, whereas smaller tumors were selected for brachytherapy. We found a significative correlation of tumor thickness (P value = 0.043) and volume (P value = 0.040) with secondary glaucoma occurrence after gamma-knife treatment. Moreover, secondary glaucoma significantly correlated with radiation retinopathy in the gamma-knife group (P value = 0.009). This study shows preliminary clinical results that could be useful for further studies with more patients and longer follow-up