Stereotactic interstitial irradiation of diencephalic tumors with iridium 192 and iodine 125: 10 years follow-up and comparison with other treatments

Abstract

The only possible treatment of non-removable tumors of the diencephalon or recurring tumors invading the diencephalon after partial resection or percutaneous radiotherapy is interstitial irradiation (Curie therapy). With the CT/MRI stereotactic method, biopsy for histological tumor classification can be performed and 125I or 192Ir implanted, provided the neuroimaging methods show the delimitation of the tumor, its diameter does not exceed 3 cm and, given the patient's condition, focal irradiation seems advisable. As of 31 August 1987, a total of 1883 cases had been stereotactically biopsied and interstitially irradiated. The indications and results are reported in 204 patients under 18 years of age with diencephalic and deep-seated astrocytomas, after a follow-up period of up to 10 years; the data were compared for tumor resection, percutaneous irradiation, and for interstitial irradiation. The latter proved to be the most effective treatment.

High-Activity ¹²⁵I Interstitial Irradiation in the Treatment of Pediatric Central Nervous System Tumors: A Pilot Study

“…Based on experiences with interstitial irradia tion in adults, there have been several series which have recently reported the use of stereotactically placed inter stitial irradiation in the treatment of childhood CNS malignancies. It is evident from table 4, that these series are divergent with respect to treatment methods, radioac tive sources used, the dose and dose rate, and tumor types treated [8,9,25], Perhaps the most striking difference in these studies is the common use of permanently placed radioactive seeds or temporary implants of several weeks duration in the 294 Fontanesi et al 125I Therapy for Pediatric CNS Tumors (2) recurrence (4) medulloblastoma ( 1 ) permanent at 125, 100-1502 N/A 1/2 meningioma (1) recurrence (2) Htou et al [8] European series and the routine use of temporarily placed seeds in North America. Series with permanently placed seeds have reported improved local control and 5-year survival rates when compared to historical institutional data with conventional irradiation [8.…”

“…Series with permanently placed seeds have reported improved local control and 5-year survival rates when compared to historical institutional data with conventional irradiation [8. 25], However, the low-dose rate associated with permanently implanted ra dioisotopes have been of apparent benefit only in lowgrade gliomas; survival in these series does not differ sig nificantly from series using only surgical resection, indi cating potentially equivalent efficacy with yet inadequate follow-up [8,25]. The few patients with high-grade malig nant neoplasms did not demonstrate improved survival.…”

“…However, the outlook is still poor for many tumors; in malignant glial tumors, local recur rence rates approach 70-90% [1,6,7]. Interstitial ra dioactive sources are now being used in children and adults in an attempt to increase the local tumor dose and, it is hoped, the rate and duration of local control [4,[8][9][10][11]. The steep dose gradient achieved with interstitial irradia tion and the refinement of stereotactic CT-guided place ment permit very precisely localized increases in the radiation dose.…”

Use of brachytherapy in children with cancer: the search for an uncomplicated cure

“…It should be noted that the use of brachytherapy in leukaemia (ICCC, group I), lymphomas and reticuloendothelial neoplasms (ICCC group II), and CNS and miscellaneous intracranial and intraspinal neoplasms (ICCC group III) that account for more than 60% of the cancers diagnosed in children is anecdotal. 17,21,22 However, brachytherapy has some potential advantages. The small size of the brachytherapy planning target volume could keep to a minimum the development of late complications that have a strong relation to a dose-volume effect such as growth retardation [2][3][4] or second primary tumours.…”

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“…Características radiológicas, histológicas e doses de radioterapia interferem na evolução, mas não foram avaliados durante a realização do presente estudo 183 . Alguns trabalhos demonstraram que a radioterapia intersticial em gliomas de baixo grau, incluindo o astrocitoma, o oligodendroglioma e o oligoastrocitoma não proporciona resultados diferentes dos da telerradioterapia ou de outras modalidades de tratamento 25,70,164,210 .…”