Late effects in high-risk neuroblastoma survivors who received MIBG therapy.

Abstract

10034 Background: Meta-iodobenzylguanidine radiolabeled with iodine-131 ( 131 I-MIBG) is used to treat high-risk neuroblastoma (HRNB) as monotherapy as well as in combination with other therapies, however associated late toxicities have not been well studied. The aim of this study was to describe the characteristics of HRNB survivors who received 131 I-MIBG and determine if 131 I-MIBG is associated with subsequent malignancy, growth impairment, thyroid toxicities, and other major organ (musculoskeletal, gonadal, gastrointestinal, cardiac, or pulmonary) toxicities. Methods: The Children’s Oncology Group LEAHRN study, ALTE15N2, evaluated HRNB survivors diagnosed after 2000 and at least five years from diagnosis. Clinical history was abstracted via study questionnaires. Clinical characteristics, treatment history, and the prevalence of late effects were descriptively summarized for subjects treated with 131 I-MIBG (cases). Subjects who did not receive 131 I-MIBG therapy were randomly selected and matched by age at diagnosis and relapse history (controls) in a 1:2 case-control study design. Chi-squared analysis was used to evaluate the association between 131 I-MIBG and late toxicities. P-values were adjusted using the Holm-Bonferroni approach. Results: Of 375 subjects enrolled in LEARHN, 32 (8.5%) received 131 I-MIBG. Of these, 17 (53%) reported relapsed or refractory disease. Mean age at 131 I-MIBG treatment was 5.1 years. 56% were male. Disease extent included an adrenal primary in 62%, multiple bone metastases in 72%, and bone marrow involvement in 63%. Thyroid toxicity (hypothyroidism, hyperthyroidism, or thyroid nodules) was similar in both groups, reported in 10/32 cases compared with 11/63 controls. One case (1/32) and four controls (4/64) reported a subsequent malignancy. Growth failure was reported in 35% of cases (11/31) and 23% of controls (16/63). Other major organ toxicities were also similar with no significant differences between cases and controls. Conclusions: In survivors of HRNB, the burden of late toxicities appeared similar in those treated with 131 I-MIBG compared to those who were not. This provides critical information for long-term follow-up care and clinical trial design.