Stereotactic radiotherapy for polypoidal choroidal vasculopathy
Reviewed by Sofia Rokerya

Polypoidal choroidal vasculopathy (PCV) is a variant of neovascular AMD. It is a disease of choroidal vasculature characterised by abnormal branching vascular network with aneurysmal dilatations (polyps). Features of PCV include pigment epithelial detachments (PED), subretinal fluid (SRF) accumulation and haemorrhage. Indocyaninegreen angiography (ICGA) is essential for the identification of polyps. Anti-VEGFs are partially effective, as polyps persist and chronic exudation can lead to continued tissue destruction and permanent vision loss. PDT with verteporfin has been proven to stabilise visual acuity. Subretinal haemorrhage after PDT can occur and the efficacy of this treatment decreases over time. Radiotherapy has been proposed for the management of nAMD as it can induce regression of new vessels and inhibit both inflammation and fibrosis. However, this treatment can be accompanied by difficulties in accurate targeting and the inability to avoid collateral damage to surrounding tissues by dispersed energy. In this study the authors evaluate the results of a single centre, pilot study for 12 eyes of 12 patients enrolled with active PCV located in an area 4mm around the fovea, who were treated with 0.5mg ranibizumab and 16 GY X-ray SRT in a single session followed by prn intravitreal ranibizumab injections. The IRay System is an SRT device that generates x-rays from a low-voltage source. Narrow collimation of the beam, as well as immobilisation and real-time tracking of the eye motion, allow precise radiation delivery onto the macular target. The mean age of the patients included in this study (10 males and two females) was 70.01 ±6.04 years, and the mean axial length of the studied eyes was 23.05 ±0.9 mm. Nine of the 12 eyes were treatment naive; the other three eyes had previously received intravitreal bevacizumab injections. Eyes were evaluated for angiographic regression of polyps, improvement in visual acuity and central foveal thickness (CFT), at three, six and 12 months. At month three, choroidal polyps were no longer visible on ICGA in 10 of the 12 eyes. These 10 eyes (83.3%) maintained complete regression of polyps at month 12. At month 12, the mean BCVA improved from 65.08 ±11.4 to 72.7 ±14.75 ETDRS letters, 10 eyes had BCVA improvement, two gained >15 letters, and five eyes gained ≥10 letters. Two eyes had BCVA decreases (one and two letters, respectively). The mean CFT significantly decreased from 372.3 ±79.6μm at baseline to 215.9 ±57.9μm at month 12 (p value of the t test <0.01). The total mean number of intravitreal ranibizumab injections was 2.9 ±1.3 (range 1–5) and 3.9 ±2.5 (range 1–8) at months six and 12, respectively. No ocular or systemic adverse events or serious adverse events were observed during the study period. There were no signs of typical radiation-induced microangiopathy, such as microaneurysms, cotton wool spots and haemorrhage, on ophthalmoscopy or in the colour photographs. A limitation of the x-ray SRT device used in this study is the fixed nature of its irradiated spot, which is 4mm in diameter and centred on the macula, with no option to adjust its size or position. PCV may present as lesions variably located at the posterior pole and often at the peripapillary area, along the vascular arcades or in the temporal part of the retina – areas that are not treated by the SRT technology evaluated in this trial. In conclusion, the data from the pilot low-voltage x-ray SRT combined with intravitreal ranibizumab for the treatment of PCV showed that this therapy is safe and potentially effective, as indicated by the observed polyp closure, decreases in CFT and improvements in visual acuity of low-voltage x-ray SRT in the treatment of PCV. 

Stereotactic radiotherapy for polypoidal choroidal vasculopathy.
Introini U, Casalino G, Triolo G, et al.
OPHTHALMOLOGICA
2015;233:82-8.