Proton beam radiotherapy (PBR) for the treatment of retinal capillary haemangioblastoma

Purpose We describe the treatment of retinal haemangioblastomas with proton beam radiotherapy as a primary treatment for juxtapapillary lesions, and as a secondary treatment in refractory cases. Methods Retrospective analysis of patients from Jan 1997–Dec 2011 with retinal haemangioblastomas treated in the Clatterbridge Cancer Centre Douglas Cyclotron. Patients were treated with reduced dose 18 Gy. Results Seven patients were treated, 4 with Von Hippel Lindau syndrome. Five cases had juxtapapillary lesions; 5 had previous failed therapy; argon laser photocoagulation‐3, photodynamic therapy‐3, intravitreal anti‐VEGF (bevacizumab/abflibercept)‐4, ruthenium‐106 plaque brachytherapy‐2, vitrectomy with endolaser‐1. Tumour diameter was 4.0–7.2 mm (mean 4.8 mm) and thickness 1.2–4.2 mm (mean 2.2 mm) with visual acuity logMAR 0.0‐hand movements (mean 0.9). Mean follow up was 24 months (12–48 m). Within three months, all lesions regressed which continued over 18 months; tumour diameter decreased by 2.7 mm (1.5 mm depth). All cases demonstrated resolution of subretinal fluid within 3–6 months; however 3 developed radiation maculopathy at 12–22 months and were treated with intravitreal bevacizumab with good effect. Five patients had visual stabilisation; one case had visual improvement and another lost vision (HM to PL) (mean 0.8) due to radiation maculopathy. Conclusions PBR is an effective treatment for retinal haemangioblastomas with good regression of tumours; side effects are fewer and less severe than that reported with external beam radiotherapy, however our rates of radiation maculopathy were >40% despite a dose of 18 Gy. Although the expense and difficulty with access may limit its use, PBR ought to be considered in refractory cases unresponsive to alternative therapies, and in juxtapapillary lesions where alternative treatments cause rapid and severe visual loss.