Preoperative [131I]metaiodobenzylguanidine therapy of neuroblastoma at diagnosis ("MIBG de novo")

Abstract

The observed response of [131I]metaiodobenzylguanidine (131I-MIBG) therapy in advanced neuroblastoma after conventional therapy had failed, the noninvasiveness of the procedure, and the high metabolic activity of untreated tumors led to a new protocol to use 131I-MIBG therapy in newly diagnosed patients instead of combination chemotherapy prior to surgery. The objectives of this study are to improve the overall outcome of patients with neuroblastoma by introducing 131I-MIBG therapy as the first therapy in the treatment schedule, in order to reduce the tumor volume, enabling adequate surgical resection and avoiding toxicity and the induction of early drug resistance. The advantages of this approach are that the child's general condition is unaffected before surgical resection is performed and that chemotherapy is reserved to treat minimal residual disease. So far, 13 patients with inoperable neuroblastoma (stage III and IV) were treated with 131I-MIBG initially and then submitted to surgery. More than 50% decrease of the volume of the primary tumor was noted in 7 of 10 evaluable patients; 8 patients have so far been operated with complete resection in 2, greater than 95% resection in 5 and 80% resection in one patient. Three patients are still undergoing 131I-MIBG treatment. The toxicity of 131I-MIBG de novo is in contrast with the previous experience of 131I-MIBG therapy after conventional therapy: only 4 patients had thrombocytopenia and only 1 of 7 patients with bone marrow involvement developed bone marrow depression.(ABSTRACT TRUNCATED AT 250 WORDS)