8-Year Survival with a Metastatic Thymic Neuroendocrine Tumor: Emphasis on Redefining “Treatment Objectives” Using “Personalized” Peptide Receptor Radionuclide Therapy with 177LU- and 90Y-Labeled Somatostatin Analogs

ABSTRACT Objective: Peptide receptor radionuclide therapy (PRRT) with 90Yttrium (90Y)- and 177Lutetium (177Lu)-labeled somatostatin analogs are the accepted standard of care for treatment of metastatic well-differentiated neuroendocrine tumors (NET) of the midgut. More aggressive NETs (e.g., of mediastinal or thymic origin) require regular follow-up and monitoring after therapy, and individualization is very important from the clinical perspective for improving outcomes and avoiding toxicity, thus improving patient quality of life (QoL). Methods: We report a case of a 58-year-old female with metastatic thymic NET who was treated with “personalized PRRT.” Results: The patient presented with inoperable mediastinal and pleural metastatic lesions. We treated the patient with 90Y- and 177Lu-labeled somatostatin analogs after positive confirmation of receptor expression on 68Gallium (68Ga)-DOTA0-Phe1-Tyr3 octreotide (DOTATOC) positron emission tomography/computed tomography (PET/CT). The patient responded well with no associated toxicity. She had three disease relapses and was treated with PRRT each time. However, disease was always confined to the mediastinum and pleura, with no distant extrathoracic spread. No hematotoxicity or nephrotoxicity was documented. Conclusion: PRRT, when “personalized” as per disease profile and patient condition, yields better outcome and survival. This case emphasizes the need for such practice in order to improve patient QoL. Abbreviations: DOTATOC DOTA0-Phe1-Tyr3 octreotide 68Ga 68Gallium 177Lu 177Lutetium NET neuroendocrine tumor PET/CT positron emission tomography/computed tomography PRRT peptide receptor radionuclide therapy QoL quality of life SMS-R somatostatin receptor 90Y 90Yttrium