Transpupillary thermotherapy (TTT) by infrared irradiation of choroidal melanoma.
We studied the destructive effect of hyperthermia at sub-photocoagulation level of 45-60 degrees C on melanomas. Optimal conditions for spreading of heat into tissue are a wavelength of 700-900 nm, a temperature of 45-60 degrees C, an exposure time of 1 minute or more, and a beam diameter of several millimeters. In hamsters with subcutaneous melanomas we obtained a tumour necrosis of 6 mm depth at 60 degrees C and one minute exposure time. We performed transpupillary thermotherapy (TTT) with a diode laser at 810 nm in patients with choroidal melanomas prior to enucleation. Treatment is based on the fortunate situation that irradiation at this wavelength combines optimal tissue penetration with a low absorption by clear ocular media of 5% or less. In 3 TTT-treated eyes histopathology showed a depth of necrosis of 0.9, 3.4, and 3.9 mm. TTT may become a new useful treatment modality for choroidal melanoma but its ultimate value has yet to be assessed.
Journée-de Korver
J G
JG
Department of Ophthalmology, Leiden University Medical Centre, The Netherlands.
Oosterhuis
J A
JA
Kakebeeke-Kemme
H M
HM
de Wolff-Rouendaal
D
D
D000818:Animals; D002830:Choroid Neoplasms / Q000473:pathology / Q000628:therapy*; D006224:Cricetinae; D004195:Disease Models, Animal; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008545:Melanoma / Q000473:pathology / Q000628:therapy*; D008647:Mesocricetus