Photon-based High-dose Single-fraction Radiosurgery, an Effective Treatment Modality for Large and Posterior Uveal Melanoma.

Abstract

Uveal melanoma (UM) is the most common primary intraocular malignant tumor. This malignancy is frequently treated using brachytherapy, stereotactic radiotherapy, or proton therapy. The objective of this study was to assess the role of stereotactic radiosurgery in the treatment of large and posterior UM. From January 2014 to July 2021, we treated 65 patients (median age=71 years; range=31-89 years) affected by UM. Inclusion criteria were Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≤2, life expectancy >6 months, tumor thickness >10 mm, diameter >16 mm or posterior UM. The treatment was delivered with a True Beam™ LINAC with arc modulation technique. All patients received 27 Gy in one fraction (biological effective dose ≈100 Gy, assuming an α/β of 10). The median follow-up was 36 (range=3-90) months. Acute toxicities were reported in 14 patients, whereas late toxicity occurred in 45 (69.2%). Fifteen patients (23.0%) underwent enucleation: eight (12.3%) for failure of local control and seven (10.7%) for late treatment co-morbidities. The 5-year local control, and progression-free, metastasis-free, enucleation-free, and overall survival rates were 80%, 43%, 62%, 65% and 56%, respectively. In multivariate analysis, tumor dimensions significantly influenced survival [larger basal diameter: progression-free [hazard ratio (HR)=2.42] and overall (HR=2.61) survival; greater thickness: overall survival (HR=2.36)]. In multivariate analysis, patients without local control had a higher risk of distant metastasis (HR=3.25). Stereotactic radiosurgery offers an effective and safe approach for selected cases of UM due to the satisfactory results in terms of local control, eye conservation and survival.