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Adult Ocular and Orbital (Ocular Adnexa) Tumors
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
P.N. Plowman, Rachel Lewis, J.L. Hungerford
By contrast, local surgical resection is technically possible for some intra-ocular melanomas. Although easier to perform on small lesions arising anteriorly in the iris and ciliary body, the complication rate is higher than for tumors that develop posteriorly in the choroid and to which the method is most applicable.4 The technique is limited to young, otherwise fit patients by the need for anesthesia, with profound hypotension a risk while cutting the highly vascular choroid. Tumors up to 15 mm in diameter may be excised, and overlying retinal detachment facilitates this operation. Local resection alone has a lower tumor control rate than plaque radiotherapy alone, so it is now advised that this operation should always be combined with adjuvant plaque therapy.5
Retinoblastoma
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Claire Hartnett, Mandeep S. Sagoo, M. Ashwin Reddy
Retinoblastoma is a very radiosensitive tumor. Although ERBT carries the risk of further tumors in the radiation penumbra and facial disfigurement, radiation can be given focally by brachytherapy using plaque applicators, avoiding these complications. Initial attempts in London by Foster Moore and Stallard used a radon seed sutured into the tumor and allowed to decay naturally [87,88]. This was replaced by Cobalt-60 applicators [89], and now the major isotopes used are Ruthenium-106 and Iodine-131. Plaque radiotherapy allows localized radiation by suturing a radioactive plaque to the eye to deliver trans-scleral radiation dose of 40–50 Gy to the apex of the tumor over several days. At the end of this period the plaque is removed. This method is effective in treating recurrences or as a single primary treatment in a location that is amenable for plaque placement.
Ophthalmic plaque brachytherapy: choroidal melanoma and retinoblastoma
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Paul T Finger, A Linn Murphree
The anatomy of most uveal melanomas is ideal for plaque radiotherapy. They are solitary tumors that arise within the uveal tract (choroid, ciliary body, and iris) of one eye. They extend from the vascular eye wall and push the retina into the avascular vitreous humor. Because ophthalmic plaques deposit most of their radiation in and around the base of the tumor, they preferentially target its vascular supply (Fig. 46.1).
Radiation retinopathy intricacies and advances in management
Published in Seminars in Ophthalmology, 2022
Noraliz García-O’Farrill, Sangeethabalasri Pugazhendhi, Peter A. Karth, Allan A. Hunter
Decreased vision secondary to macular edema is the earliest symptom of radiation-induced retinopathy, as stated by Horgan et al. in a study of retinopathy following plaque radiotherapy for uveal melanoma. OCT evidence of macular edema was present in 33% of study subjects in the absence of clinical evidence of radiation retinopathy, asserting that macular edema can be found on OCT approximately five months earlier than clinically evident radiation retinopathy.26
Outcomes of fractionated CyberKnife radiosurgery in patients with choroidal malignant melanoma
Published in Acta Oncologica, 2022
Ceyda Baskan, Ebru Atasever Akkas, Sabite Emine Gökce, Sibel Ozdogan
The current gold standard for the treatment of uveal melanomas is the proton beam radiotherapy [11]. However, it is not a readily available and easily accessible radiotherapy option in many centers and even in many countries due to the high costs [12]. Therefore, radioactive plaque brachytherapy is generally the first choice of treatment. Radioactive plaque brachytherapy is performed by using isotopes iodine-125, ruthenium-106, or palladium-103. Iodine plaques emitting gamma radiation are effective for tumors in the range of 8–10 mm and ruthenium plaques emitting beta radiation for up to 5 mm [4,13,14]. Especially in large tumors, it might not be possible to deliver large doses of radiotherapy (80–100 Gy) to the tumor site. That is why, higher local recurrence rates (10.3%) were reported with plaque brachytherapy [15] than with proton-beam radiotherapy (3%).16 Moreover, conventional plaque radiotherapy can be technically difficult in both insertion and placement of the plaques, especially when treating juxtapapillary tumors because of the proximity to the optic nerve. Williams et al. [17] reported cases in which the posterior edge of the juxtapapillary plaque was displaced away from the optic nerve, as demonstrated by MRI, in cadaver eyes. Harbor et al. [18] reported that after initial plaque placement by transillumination and indirect ophthalmoscopy, echography identified that 14% of the plaques were decentered by more than 2 mm with at least one tumor margin uncovered by the plaque. In a more recent study, regardless of the radio-isotopes used and plaque designs (notched vs non-notched), a two to threefold increased risk of treatment failure with plaque brachytherapy has been reported for choroidal melanomas touching the optic disk [19]. Therefore, the need for safer and noninvasive treatment modalities for uveal melanomas caused rising interest in stereotactic radiosurgery which provided promising results [20].
Ruthenium plaque radiotherapy in the current era of retinoblastoma treatment
Published in Ophthalmic Genetics, 2022
Guy S. Negretti, Hibba Quhill, Catriona Duncan, Tanzina Chowdhury, Ian Stoker, M. Ashwin Reddy, Mandeep S. Sagoo
Clinical and tumor features are shown in Table 2. Plaque radiotherapy was used as a primary treatment in one patient (8%). This patient had a long-standing retinoma that converted to retinoblastoma after 4 years of follow-up. All the other patients in the study (n = 11, 92%) had plaque radiotherapy performed as salvage therapy to treat retinoblastoma relapses that were resistant to other forms of treatment.