225Ac-DOTATOC–Targeted Somatostatin Receptor α-Therapy in a Patient With Metastatic Neuroendocrine Tumor of the Thymus, Refractory to β-Radiation

Abstract Somatostatin receptor–targeted α-therapy using α-emitter 225 Ac-labeled somatostatin analogs has been suggested as a treatment option in advanced metastatic neuroendocrine tumors (NETs) failing treatment with β-emitters, such as 177 Lu or 90 Y. Thymus NETs are rare and usually more aggressive than other neuroendocrine tumor entities. We present here a case with β-radiation refractory metastatic thymus NET, who demonstrated an excellent therapy response (molecular and morphological remission, as well as significantly improved clinical symptoms) after 225 Ac-DOTATOC–targeted α-therapy, without any adverse effects during the treatment or in the follow-up period.