Treatment of advanced neuroblastoma with I-131 meta-iodobenzylguanidine

Benzylguanidine is a chemical selectively taken up by cells of the sympathetic nervous system. This guanethidine derivative can be labelled with radioactive iodine, and both the 131-I and 123-I radioisotopes of iodine have been used in scintigraphic studies. In such studies, the selective uptake of the radioactive iodobenzylguanidine can be visualized using scintillation detectors. This technique has been used to image tumors such as pheochromocytoma, medullary thyroid carcinoma, paraganglioma, and neuroblastoma. The same selective uptake might be exploited in a therapeutic capacity as well. If the tumors take up a small dose of radioactive tracer for imaging, they might take up a larger dose of radioactive compound which might serve as a direct source of radiotherapy within the cancer itself. This technique was evaluated in the treatment of 31 children with advance neuroblastoma. All 31 patients had tumors that were visible on scintigraphy, indicating that their tumors took up the radioactive compound. All 31 patients had either failed to respond to conventional therapy or relapsed after conventional therapy. The children were given doses of radioactive I-131 meta-iodobenzylguanidine ranging from 2.8 to 6.0 gigaBecquerels (a gigaBecquerel is radioactivity at a level of one billion radioactive disintegrations per second). Two complete and four partial response were observed. These patients relapsed and all 31 patients are either dead or alive with disease. (Consumer Summary produced by Reliance Medical Information, Inc.)