Aims To describe results after neoadjuvant proton beam irradiation followed by transscleral resection of large uveal melanoma.

Methods Retrospective interventional case series, including 106 consecutive patients. Local tumour control, enucleation and metastasis development were assessed with survival curves. Predictors of local recurrence and metastasis were investigated with log-rank testing.

Results Mean follow-up was 3.2 years. Local recurrence occurred in five cases with an estimated risk of 4.2% and 10.4% at 3 and 5 years after treatment, respectively. Enucleation was performed in 10 cases with an estimated risk of 9.2% and 18.4% at 3 and 5 years, respectively. Significant risk factors for local recurrence were not evident. Metastasis was estimated to occur in 28.4% at 3 years and 40.3% at 5 years, correlating with patient's age only (p=0.01). Seventy four patients (69.8%) underwent vitreoretinal surgery for complications after tumour resection. Median visual acuity (VA) was 20/50 at diagnosis and 20/400 in the third year after treatment. VA preservation of 20/200 or better was achieved in 33 patients (31.1%).

Conclusion Neoadjuvant proton beam irradiation may help to prevent local recurrence after transscleral resection. Additional vitreoretinal surgery was frequently needed in the presented series. The majority of patients avoided enucleation and functional blindness.