Diagnostic methods and therapeutic options of uveal melanoma with emphasis on MR imaging—Part II: treatment indications and complications

Abstract

Therapy of uveal melanoma aims to preserve the eye and its function and to avoid metastatic dissemination. The treatment choice is difficult and must keep into account several factors; the therapeutic strategy of uveal melanoma should therefore be personalized, sometimes requiring to combine different treatment techniques. Nowadays globe-sparing radiotherapy techniques are often preferred to enucleation. Plaque brachytherapy, the most commonly used eye-preserving therapy, is suitable for small- and medium-sized uveal melanomas. Proton beam radiotherapy is indicated for tumours with noticeable size, challenging shape and location, but is more expensive and less available than brachytherapy. Enucleation is currently restricted to advanced tumours, uveal melanomas with orbital or optic nerve involvement, blind and painful eyes because of treatment-related complications (neovascular glaucoma, chronic inflammatory processes). The effect of proton beam therapy on neoplastic tissue is related to direct cytotoxic action of the radiations, impairment of neoplastic vascular supply and immunologic response. Complications after radiotherapy are frequent and numerous and mainly related to tumour thickness, radiation dose and distance between the tumour and optic nerve. The purpose of this pictorial review is to provide the radiologists with awareness about diagnostic methods and therapeutic options of uveal melanoma. In the present second section, we discuss the therapeutic management of uveal melanoma, describing the main ocular-conserving radiotherapic techniques. We subsequently present an overview of the effects of radiations on neoplastic tissue. Lastly, we review ocular complications following radiotherapy that should be evaluated by radiologists during follow-up MRI examinations.

MR imaging characteristics of uveal melanoma with histopathological validation

“…Imaging UM with MR requires a dedicated eye protocol consisting of 2D MS TSE sequences, which are indispensable for delineating tumor boundaries; 3D TSE sequences, which allow retrospective reformatting in all directions and 3D reconstructions, and are essential to assess tumor geometry and accurate measurements; and DWI and PWI sequences, which aid in the differential diagnosis, and potentially, provide prognostic information, predict treatment response, and permit earlier assessment of tumor response to radiotherapy than US [ 3 , 8 , 11 , 14 – 18 ].…”

New Perspectives for Eye-Sparing Treatment Strategies in Primary Uveal Melanoma

“…Furthermore, large tumors may be removed by transscleral resection, but eye-retaining treatment may be applied if patients do not qualify for radiotherapy. Local resection could be used when iris and ciliary body melanomas occur [ 3 , 56 , 57 ]. Compared to ( 125 I) brachytherapy, transscleral tumor resection treatment incidence of secondary glaucoma is lower, and patients retain a better visual function [ 58 , 59 ].…”

Histopathologic and MR Imaging Appearance of Spontaneous and Radiation-Induced Necrosis in Uveal Melanomas: Initial Results

“…Enucleation of the eyeball is currently performed in selected cases [ 33 , 34 ]. It is distinguished as: (a) primary when patients have not undergone any previous radiation eye-preserving therapy, and (b) secondary when patients have been formerly treated with laser techniques or radiation therapy [ 35 ].…”