Retinal capillary haemangioblastomas (RCH) may occur sporadically or as part of von Hippel-Lindau disease (VHL), an autosomal dominant condition. Mutations in the VHL gene, a tumour suppressor gene, cause abnormal production of the VHL protein and the subsequent uncontrollable cellular division results in the development of vascular tumours and cysts in the central nervous system and elsewhere. Approximately 2–4% of intraocular haemangioblastomas are juxtapapillary where the risk of visual loss is higher [1] and the destructive effects of laser photocoagulation, cryotherapy and brachytherapy usually lead to severe and permanent visual loss.

We report our experience with proton beam radiotherapy (PBR) of RCH located at the optic disc or unresponsive to other treatments. Four daily fractions were administered, with a total dose of 18 proton Gy.

Eight patients (three male, five female) were treated with mean age 49 years (range, 29–84 yrs). Four patients had a genetic diagnosis of VHL. All patients had juxtapapillary haemangioblastomas and two also had mid peripheral-lesions.

Basal tumour diameter at presentation was 3.1–7.2 mm (mean 5.0 mm) with thickness of 1.2–4.2 mm (mean 2.4 mm). Visual acuity ranged from 0.0 logMAR to hand movements (mean 0.9). All patients had exudative changes. Six patients had previous unsuccessful therapy: argon laser photocoagulation (n = 3), photodynamic therapy (n = 4), intravitreal anti-VEGF injections (bevacizumab or abflibercept) (n = 4), ruthenium-106 plaque brachytherapy (n = 2) and vitrectomy with endolaser (n = 1) (Table 1).

Table 1 Summary of previous treatments, vision and tumour characteristics for each case
Full size table

All patients were followed up for 3–7 years. Within three months of treatment, all haemangioblastomas regressed (mean longitudinal measurements 3.2 mm, depth 1.8 mm) with a decrease in tumour volume (decrease 1.6 mm longitudinally and 1.2 mm depth), continuing over 3 years. All lesions demonstrated resolution of subretinal fluid within 3–6 months; however three patients developed radiation-induced maculopathy between 12 and 22 months and were treated with intravitreal bevacizumab. Vision was stabilised in all cases but the majority had very poor vision at baseline and no improvement following therapy (baseline logMAR 0.0-Hand motions; last follow up 0.0-Perception of light; Table 1).

Treatment of juxtapapillary capillary haemangioblastomas is challenging. External beam radiotherapy (EBR) [2] has been successful but increases the risk of secondary central nervous system malignancies [3], as well as the potential development of radiation effects to both the retina and the optic nerve. Proton beam therapy has been described in two small series utilising 20 Gy but 3/8 still developed optic neuropathy or maculopathy [4, 5].

PBR may be considered in patients where other treatment modalities fail to control aggressive disease in patients with juxtapapillary or peri-macular lesions. This may help with control of eye threatening exudative complications. Although the treatment enables control of tumour progression and growth, the high rate of radiation maculopathy despite reduced radiation doses is disappointing. As such this treatment should be considered only as a stabilising strategy as visual acuity does not improve; laser therapy is an alternative strategy, however in the peri-papillary region will certainly result in visual field defects.