Proton beam therapy for iris melanomas

Abstract

Aims To describe the results in terms of local control, eye preservation and systemic evolution of iris melanomas treated by proton beam irradiation.

Don’t it make my blue eyes brown: heterochromia and other abnormalities of the iris

“…[331][332][333][334][335][336][337][338][339][340][341][342][343][344][345] Alternative treatment modalities include plaque brachytherapy 346,347 and proton beam irradiation. [348][349][350] The management of diffuse iris melanomas is problematic and most are probably best treated by enucleation, although irradiation may be tried in cases where the patient is reluctant to suffer loss of their eye. 333 The apparently low risk of metastatic disease in cases of iris melanoma contrasts with that of choroidal and ciliary body tumours where the mortality rates are significantly greater.…”

Multifocal iris melanoma treated with total anterior segment palladium-103 plaque radiation therapy

“…Though some melanomas were described as diffuse, one cannot determine how many required including the entire anterior segment within the targeted zone (beneath the plaque). Regarding proton beam, most studies refer to localized iris melanomas [8,9]. Rundle et al described treatment of 15 cases defined as "non-resectable" iris melanomas treated with 53.1 Gy, delivered in four fractions [4].…”

“…Though the radiation within the anterior segment is more homogeneous, the interaction in tissue (the relative biologic effectiveness) of these two sources are different [10]. Further, the gold backing of the plaque will block more than 99.95% of radiation to the sides and posterior to the plaque [7][8][9][10]. Lastly, delivering a continuous low dose over 5-7 days is radiobiologically different from giving the same dose given over seconds to minutes on 3-5 consecutive days.…”

Utility of a Biopsy in Suspicious Pigmented Iris Tumors

“…UBM, which allows for strong reproducibility of tumor dimensions, has increased reliability in periodic observation as a primary approach of suspicious pigmented iris lesions [11][12][13] . Moreover, in the case of documented lesion growth, medically uncontrollable IOP or progressive angle pigment dispersion, which is clinically indicative of diffuse anterior segment melanoma, we now consider proton beam radiotherapy -the effectiveness of which has been demonstrated for circumscribed iris melanoma [14][15][16] -of the whole anterior segment. Consequently, enucleation is avoided, and the need for histopathologic proof through prior biopsy is reduced.…”