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Metronidazole and interstitial implantation in the treatment of extensive recurrent head and neck cancers
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CONSERVATIVE
MANAGEMENT OF CHOROIDAL MELANOMA USING
IODINE-125 OPt!Tt!ALFlIC APPLICATORS Marvin Rotman, M.D., (1) and Samuel Packer, M.D. (2) (1) New York Medical Colleqe, Radiation Theraoy Department (2) North Shore Universit,y Hosoital, Cornell University Medical Colleqe, Oohthalmoloqv Department The ophthalmologic literature in recent .vears has seriousl,v questioned the effectiveness of radiation in the treatment of choroidal melanoma. Recent articles have emnhasized that the tumor is resistant to radiation and that the doses necessary for sterilization .vield an unacceptable morbidity. When radiation therapy has been advocated, strict limitations have been placed on its application includinq selection of tumor size and the position of the tumor in relation to vital structures. The use of Cobalt-60 onhthalmoloqic applicators, although used successfully in terms of survival, have qiven severe comolications. A major shortcomina of the Cobalt-60 olaque has been the limited size available and the inability of the oohthalmoloqist to tailor the plaque to fit the tumor. Histonatholoqic studies on post-irradiation enucleated eyes have shown evidence of necrosis of tumor centrally under the plaque while at the periphery or outer edqe of the olaque, viable tumor exists.
In an effort to improve local control, decrease radiation complications, and reduced nersonnel radiation exposure, the low-enerqy emitter Iodine-125 Less than .05 millimeters of qold can rewas substituted for the Cobalt-60. duce 90% of the photons emitted from Iodine-125 and a olaque can be very easily fashioned to fit the tumor. Comouterized dosimetr,y comnarinq Cobalt60 and Iodine-125 applicators show that if radiation intensity is adjusted to provide equal doses from both isotopes at 10 mm, a difference of 16% exists at 30 mm. With most tumors less than 12 mm in heiqht, no siqnificant dose anisotrophy occured. A Greene melanoma was grown in the choroid of the hamster and rabbit and Histopatholoqic irradiated with removable Iodine-125 oohthalmic applicators. examination of the treated eye gave valuable information as to the effects of radiation. There was evidence of an increased radiobiological effectiveness with the Iodine-125. Delivering comparable doses from both plaques the tumor irradiated by Iodine-125 was completely obliterated while islands of seeminqly viable cells existed in the Cobalt-60 treated eye. These findings were then extrapolated into the treatment of human choroidal tumors. Seven patients with choroidal melanomas where treated with removable Each had a plaque fashioned to fit the Iodine-125 ophthalmic applicators. tumor and each received 8500 rads in one insertion. Six of seven patients are a minimum of one year in follow-up and none show evidence of tumor qrowth One oatient had an eye enucleated secondary to hemoror radiation damage. Details of these cases will be described. It is antirhage at six months. cipated that individually designed plaques containinq Iodine-125 can be incorporated into the treatment of retinoblastoma.
64
ASTR 21st Annual Meeting
CONSERVATIVE
MANAGEMENT OF CHOROIDAL MELANOMA USING
IODINE-125 OPt!Tt!ALFlIC APPLICATORS Marvin Rotman, M.D., (1) and Samuel Packer, M.D. (2) (1) New York Medical Colleqe, Radiation Theraoy Department (2) North Shore Universit,y Hosoital, Cornell University Medical Colleqe, Oohthalmoloqv Department The ophthalmologic literature in recent .vears has seriousl,v questioned the effectiveness of radiation in the treatment of choroidal melanoma. Recent articles have emnhasized that the tumor is resistant to radiation and that the doses necessary for sterilization .vield an unacceptable morbidity. When radiation therapy has been advocated, strict limitations have been placed on its application includinq selection of tumor size and the position of the tumor in relation to vital structures. The use of Cobalt-60 onhthalmoloqic applicators, although used successfully in terms of survival, have qiven severe comolications. A major shortcomina of the Cobalt-60 olaque has been the limited size available and the inability of the oohthalmoloqist to tailor the plaque to fit the tumor. Histonatholoqic studies on post-irradiation enucleated eyes have shown evidence of necrosis of tumor centrally under the plaque while at the periphery or outer edqe of the olaque, viable tumor exists.
In an effort to improve local control, decrease radiation complications, and reduced nersonnel radiation exposure, the low-enerqy emitter Iodine-125 Less than .05 millimeters of qold can rewas substituted for the Cobalt-60. duce 90% of the photons emitted from Iodine-125 and a olaque can be very easily fashioned to fit the tumor. Comouterized dosimetr,y comnarinq Cobalt60 and Iodine-125 applicators show that if radiation intensity is adjusted to provide equal doses from both isotopes at 10 mm, a difference of 16% exists at 30 mm. With most tumors less than 12 mm in heiqht, no siqnificant dose anisotrophy occured. A Greene melanoma was grown in the choroid of the hamster and rabbit and Histopatholoqic irradiated with removable Iodine-125 oohthalmic applicators. examination of the treated eye gave valuable information as to the effects of radiation. There was evidence of an increased radiobiological effectiveness with the Iodine-125. Delivering comparable doses from both plaques the tumor irradiated by Iodine-125 was completely obliterated while islands of seeminqly viable cells existed in the Cobalt-60 treated eye. These findings were then extrapolated into the treatment of human choroidal tumors. Seven patients with choroidal melanomas where treated with removable Each had a plaque fashioned to fit the Iodine-125 ophthalmic applicators. tumor and each received 8500 rads in one insertion. Six of seven patients are a minimum of one year in follow-up and none show evidence of tumor qrowth One oatient had an eye enucleated secondary to hemoror radiation damage. Details of these cases will be described. It is antirhage at six months. cipated that individually designed plaques containinq Iodine-125 can be incorporated into the treatment of retinoblastoma.
64
ASTR 21st Annual Meeting