Pediatric brachytherapy. The St. Jude Children's Research Hospital experience

The use of interstitial, intracavitary, and permanent placement of radioactive isotopes has become a common practice in adult oncology patients based on numerous reports indicating improved local control and survival when used. These same irradiation techniques and treatments have been infrequently used for children with malignant disease despite known dose localization properties that allow for highly focal irradiation delivery with rapid reduction of the dose in nearby normal tissues. The noted benefit of decreased late complications noted in the adult series is also attractive, especially when considering the treatment of children.

Between May, 1981 and December 15, 1992, 46 children with non-CNS primary malignancy received 50 brachytherapy applications for primary therapy (n = 11 sites), as a boost in conjunction with external beam irradiation (n = 16 sites), or as treatment of recurrent disease or a second malignant neoplasm in a previously irradiated region that precluded further external irradiation or for metastatic disease (n = 23 sites). The most common tumor histologies were rhabdomyosarcoma (n = 14), soft tissue sarcoma (n = 10) and retinoblastoma (n = 10). Patient age at implantation ranged from 8 weeks to 24 years; follow-up maintained in all patients and has ranged from 2-115 months (median, 39 months).

Forty-three of 50 sites receiving brachytherapy have maintained continuous disease free intervals, ranging from 2 to 115 months postimplantation (median, 41 months). The seven local failures occurred 2-20 months postimplant (median, 6 months). Severe complications occurred in 12 patients, two which were life threatening but resolved without further incident.

Based on this ongoing clinical investigation, the authors recommend brachytherapy for selected pediatric malignancies and continue to evaluate the various factors associated with local control, local failures, and complications.