Proton beam radiotherapy for choroidal and ciliary body melanoma in the UK-national audit of referral patterns of 1084 cases.

INTRODUCTION: Proton beam therapy has been utilised for the treatment of uveal melanoma in the UK for over 30 years, undertaken under a single centre. In the UK, all ocular tumours are treated at one of four centres. We aimed to understand the variation in referral patterns to the UK proton service, capturing all uveal melanoma patients treated with this modality. METHODS: Retrospective analysis of data regarding all patients treated at the Clatterbridge Proton service between January 2004 and December 2014. RESULTS: A total of 1084 patients with uveal melanoma were treated. The mean age was 57 years (range 9-90 years), basal diameter of 11.5 mm (range 2.0-23.4 mm) and tumour thickness of 3.9 mm (range 0.1-15.4 mm). The majority were TNM stage I (39%) or II (36%). The distance to the optic nerve varied from 0 to 24.5 mm with 148 (14%) of patients having ciliary body involvement. There were variations in the phenotypic characteristic of the tumours treated with protons from different centres, with London referring predominantly small tumours at the posterior pole, Glasgow referring large tumours often at the ciliary body and Liverpool sending a mix of these groups. DISCUSSION: In the UK, common indications for the use of proton treatment in uveal melanoma include small tumours in the posterior pole poorly accessible for plaque treatment (adjacent to the disc), tumours at the posterior pole affecting the fovea and large anterior tumours traditionally too large for brachytherapy. This is the first UK-wide audit enabling the capture of all patients treated at the single proton centre.

Dysfunctional uveoscleral pathway in a rat model of congenital glaucoma.

UNLABELLED: The purpose of the study was to investigate the presence of the uveoscleral pathway in the normotensive rat (NR) and in a rat model of congenital glaucoma (CGR). We injected the fluorescent tracer 70-kDa dextran rhodamine B in the anterior chamber of four NRs and four CGRs. At 10 and 60 minutes after injection, rats were euthanized by CO2 inhalation and eyes were enucleated. Cryosections were prepared and analyzed using fluorescent microscopy. Hematoxylin-eosin staining and electron microscopy of the anterior chamber angle (ACA) were performed. At 10 minutes after injection, fluorescent tracer was detected in the iris root and ciliary processes of NRs and CGRs. At 60 minutes, NRs showed prominent signal in the suprachoroidal, whereas, in the CGRs, tracer was barely detectable. Histology of the anterior chamber revealed the presence of an open ACA and electron microscopy confirmed the normal structure of the ciliary body in CGRs. CONCLUSIONS: Our results document the presence of an uveoscleral pathway in the normotensive rat. The rat model of congenital glaucoma shows severe impairment of the uveoscleral pathway, suggesting that alterations of the uveoscleral outflow might play a role in the pathogenesis of CG.