Molecular radiotherapy for adult type metastatic neuroendocrine tumours in children

Paraganglioma, phaeochromocytoma and gastroenteropancreatic neuroendocrine tumours are rare in childhood. Molecular radiotherapy is one potential treatment for locally inoperable or metastatic disease. This study reviews the use and efficacy of molecular radiotherapy with both [¹³¹I] meta iodobenzylguanidine (mIBG) and [¹⁷⁷Lu] DOTATATE in this patient group.

This is an observational cohort study of all patients aged less than 18 years with adult type metastatic neuroendocrine cancers treated with molecular radiotherapy from 2003 to 2023 in one national referral centre.

Twelve patients, six male and six female, were treated. The median age at diagnosis was 12 years 3 months (range 7 years 11 months to 15 years 5 months), and at first molecular radiotherapy treatment was 13 years 7 months (range 8 years 8 months to 16 years 2 months). Nine had paraganglioma or phaeochromocytoma, three had other neuroendocrine tumours. Three received [¹⁷⁷Lu] DOTATATE only, four received [¹³¹I] mIBG only, and five received both radiopharmaceuticals. Three patients had rapid disease progression and died within a year. Following initial treatment of the others, two had a complete response, four had a partial response, one had stable disease, and two had a mixed response. Nine patients remain alive, at a median of 5 years 0 months (range 2 years 4 months to 21 years 5 months) after start of treatment.

Molecular radiotherapy can be beneficial, and may provide good disease control for long periods in a proportion of these patients. Combining different radiopharmaceuticals may be of value.