SUN-914 Peptide Receptor Radionuclide Therapy for an Inoperable Small Cell Neuroendocrine Tumor in the Philippines

Background: Peptide Receptor Radionuclide Therapy treatment for neuroendocrine tumors is a well-tolerated treatment option for patients not amenable to receiving chemotherapy and radiotherapy. Clinical Case: A 42-year-old female was evaluated by a cardiologist for complaints of new onset recurrent throat discomfort, chest pain and palpitations. Two-Dimensional echo showed a large extra-cardiac mass compressing the main pulmonary artery. Chest CT with contrast reveal a 5.8 x 6.0 x 7.2 cm enhancing lobulated anterior mediastinal mass. Attempts to excise the mass failed due to the proximity to major blood vessels. Biopsy revealed a Carcinoid Tumor that was Chromogranin A positive but was asymptomatic for carcinoid syndrome. Everolimus treatment was given but was halted due to stomatitis. The patient remained fully functional. Re-evaluation of the mass with FDG PET show an increase in tumor size. Biopsy tissue re-testing showed small cell neuroendocrine carcinoma. Urine 5-hydroxyindoleacetic acid, plasma 5-hydroxyindoleacetic acid, and serum Chromogranin A were normal. A (68)Ga-DOTATATE PET/CT scan reveal a slight increase in the mass that was intensely DOTATATE-avid. Two sessions of Peptide Receptor Radionuclide Therapy (PRRT) Lutetium-177 DOTATATE given at an 8-month interval were given. SPECT/CT re-evaluation showed good response and no evidence of metastases. A (68)Ga-DOTA-octreotate PET-CT scan was done and showed good response to treatment. According to treatment guidelines, small cell neuroendocrine carcinoma that are non-resectable are treated with radiotherapy plus chemotherapy. But since the patient is fully functional and has minimal symptoms, other means of treatment such as PRRT may be well suited due to good tolerability and good treatment outcomes. Conclusion: PRRT is a promising treatment for NETs that is well tolerated giving better functionality and quality of life for patients opting not to undergo chemotherapy and radiotherapy. Reference: Cadiot, G. (2019). French and European Neuroendocrine Tumor Society consensus guidelines. Annales d’Endocrinologie, 80(3), p.174.