Background: Primary ovarian insufficiency (POI) is a noted late effect in childhood cancer survivors treated with alkylating agents or after radiation to a field that includes the ovaries. Gonadal failure in children with neuroblastoma (NBL) who were exposed to 131I- metaiodobenzylguanidine (MIBG) has only been reported in those who were also treated with chemotherapy. In these cases, the cause of gonadal failure was assumed to be the cytotoxic therapy. Here, we present the first two cases of POI after 131I-MIBG treatment only for NBL, indicating that 131I-MIBG treatment may have a causative role.
Patients: During follow-up after treatment for NBL in childhood, elevated gonadotropins were found in a 12-year-old girl and an 11-year-old girl (FSH values, 105 and 161 U/L, respectively), indicating POI. The first patient had been diagnosed at the age of 17 months with sacrally located (intraspinal) NBL. Treatment consisted of five courses of 131I-MIBG and local resection. The second patient had been diagnosed at the age of 8 months with an abdominal (intraspinal) NBL. She had been treated with acute (neuro) surgery for decompression of her intraspinal tumor causing neurological symptoms, followed by two courses of 131I-MIBG therapy. Both girls had normal karyotypes (46, XX). No other cause for the ovarian failure was found. Estrogen suppletion was started, and patients and parents were counseled regarding fertility options.
Conclusion: These two cases suggest that exposure to 131I-MIBG may damage the female gonads. Clinicians caring for childhood cancer survivors should be aware of the risk of POI after 131I-MIBG treatment. Prospective studies are warranted to confirm our observations.