Radiotherapy for malignant melanoma of the choroid.

Abstract

IT is evident from current ophthalmic literature that there is still an unawareness of the possibility and the value of radiotherapy for some patients with malignant melanoma of the choroid, despite the publication of several papers and lectures about this matter. So this paper is submitted as a reasonable excuse for publishing the results of the first hundred patients with malignant melanoma of the choroid treated by radioactive applicators between 1939 and 1964 (99 by 60Co applicators and one by radon seeds in 1939). The presence of malignant melanoma of the choroid, whether in an only eye or when the other eye is blind or almost so from either disease or amblyopia and in rare cases when this tumour is bilateral, would naturally incite even the most orthodox-minded surgeon to seek an alternative treatment to the tragic consequence of excision. It is fortunate that freedom of thought in medicine still allows us to challenge accepted and time-honoured therapeutic procedures and beliefs. Among these has been the authoritative statement that malignant melanomata are radioresistant for irradiation. This depressing attitude is untrue, for a number of malignant melanomata of the choroid are in fact radiosensitive and become reduced to a flat, pigment-stippled scar (Fig. 1). The effective application of radiotherapeutic 15.12.60 3.10.61 FIG. 1.-Malignant melanoma before and after radiotherapy, showing flat, pigment-stippled scar.

Radiotherapy for ocular tumours

“…These were later superseded by Co-60 plaques. 5 Lommatsch was the first to use Ru-106 plaques 6 and Sealy et al 7 was the first to use I-125 to treat ophthalmic tumours. Table 1 shows the characteristics of the various isotopes used, including whether b or g emitters, the half-life (time taken to decay to half the activity), energy, half value layer in tissue (mm of tissue required to reduce the energy to half), useful range in tissue, sclera to apex dose, and the amount of lead (Pb) required to block the radiation by 95%.…”

Braquiterapia com Cobalto 60 para o tratamento do melanoma da úvea: análise dos fatores prognósticos para melhor resposta local

“…A preocupação com o montante de retenção da função visual pós-tratamento braquiterápico é evidente desde os primeiros relatos (19) , porém a quantidade de acuidade visual considerada, por cada autor, como "preservação de visão útil" é bastante variável e subjetiva. De maneira geral, podemos considerar que resultados visuais satisfatórios foram observados utilizando-se os diferentes isótopos disponíveis, em 30% a 75% dos casos (12,(16)(17)(18) .…”

“…O índice de complicações relatado está em torno de 40%, sendo as tardias as principais, ocorrendo frequentemente 2 anos após o tratamento (3) . O controle tumoral pode ser considerado bom, com falha relatada entre 4% e 33% (14)(15)(19)(20)(21)(22)(23)(24) . Fatores aparentemente relacionados com a falha do controle tumoral local e a ocorrência de complicações são: o tamanho (16,25) e localização do tumor tratado (15,(22)(23) , assim como a dose e taxa de dose radioativa utilizada (12,15,22) .…”

Gold nanoparticle‐based brachytherapy enhancement in choroidal melanoma using a full Monte Carlo model of the human eye

“…Several isotopes, including 125 I and 103 Pd are used in the brachytherapy of choroidal melanoma 12 , 13 , 14 . Increasing the dose to the tumor, while decreasing the dose to the normal tissues remains as one of the biggest challenges in radiation therapy.…”