Photon-based high-dose single-fraction radiosurgery, an effective treatment modality for recurrent uveal melanoma.

Introduction: To evaluate and report the outcome of a patient with locally recurrent uveal melanoma (UM) previously treated with brachytherapy (BT), using a second personalized globe-sparing radiotherapy approach. Material and methods: In June 2020, a 78-year-old man arrived at our institution with diplopia and suspected uveal melanoma. At the ophthalmological evaluation (B-scan and A-scan ultrasonography) a lesion in the right eye at 6-7 hours of about 5 mm thickness, with internal lacunar areas, approximately 7 mm away from the limbus, was observed. The patient underwent ruthenium plaque BT at a total dose of 110 Gy prescribed to the apex of the tumour. At the follow-up, the lesion was under control until September 2021, but it recurred with a satellite exudative detachment in the lower and temporal sectors 7-10 hours. At the B-scan the lesion had a maximum thickness of 4.6 mm. Subsequently, in a multidisciplinary discussion, one single fraction stereotactic radiosurgery was scheduled. The prescribed dose was 27 Gy in the de-novo lesion and 24 Gy in the previously irradiated site. Stereotactic radiosurgery was performed in October 2021. Results: The time interval between the 2 treatments was 15 months. Twenty months after recurrence, local tumour control was observed, and no metastases were detected on follow-up examinations. No severe acute or late toxicity was observed due to the retreatment. Conclusions: Photon stereotactic radiotherapy is a feasible, acceptably tolerated modality, and it represents an eye-preserving treatment also for patients with recurrent UM unfit for BT.