BRACHYTHERAPY IN THE COMBINED-MODALITY TREATMENT OF PEDIATRIC MALIGNANCIES - PRINCIPLES AND PRELIMINARY EXPERIENCE WITH TREATMENT OF SOFT-TISSUE SARCOMA (RECURRENCE) AND EWINGS-SARCOMA

Radiotherapy is an integral part in the treatment of soft tissue and E wing's sarcoma in children. By brachytherapy a high dose can be delive red in a restricted volume with sparing of normal tissues surrounding the target. Taking into account this principle potential benefit brach ytherapy may play some role in the local treatment especially in child ren. However, only limited experience with pediatric brachytherapy has been reported apart from a few centers, which have gained their exper ience with Low-Dose-Rate (LDR)-brachytherapy. Since 1991 - 12 patients with soft tissue sarcoma and 6 patients with Ewing's sarcoma were tre ated with High-Dose-Rate (HDR) and Pulse-Dose-Rate (PDR)-brachytherapy at the departments of radiotherapy in Munster, Kiel and Vienna. The c ombined modality treatment was performed according to the CWS-86/91, E ICESS-92 and CESS/CWS-REZ-91 protocols. In 8 patients with soft tissue sarcoma brachytherapy was part of the recurrence treatment regime, in 4 patients brachytherapy was part of the primary treatment alone or i n combination with external beam therapy. In HDR-treatment a dose of 1 5 to 43 Gy was delivered in 3 to 16 fractions, in PDR-treatment 13 to 36 Gy in fractions of 1 Gy/hour. Follow-up is 3-39 months (median 14 m onths). 7 patients show no evidence of disease, 9 patients are locally controlled and 3 patients progressed locoregionally. In 6 patients wi th Ewing's sarcoma brachytherapy was performed intraoperatively as a b oost treatment after external beam therapy (50-55 Gy), if no wide rese ction could be achieved within first line-treatment. A dose of 10-12 G y was applied in one fraction in a limited volume (20-50 ccm) at the t ime of surgery. Follow-up is 13-26 months (median 21 months). There is no evidence of disease in all patients, perioperative and subacute mo rbidity was not increased. These encouraging preliminary results with HDR/PDR-brachytherapy must be further evaluated prospectively and syst ematically within an interdisciplinary approach by some specialized co llaborating centers, which not only have the equipment (HDR/PDR/ (LDR) -brachytherapy) but also can meet the complex demands to accumulate th e necessary experience.