Bilateral orbital soft tissue metastases from Renal Neuroendocrine Tumor: successful Theranostic application of ⁶⁸Ga/¹⁷⁷Lu-DOTATATE with improvement of vision

Abstract

Gratifying clinical response obtained in the clinical setting of bilateral orbital metastases from renal neuroendocrine tumor (NET) is reported. Methods: A 53 year-old male, diagnosed case of renal NET (MIB1 index-4%), with symptoms of skeletal and abdominal pain, proptosis and decrease in vision of left eye, was found to harbor bilateral orbital soft tissue lesions on ⁶⁸Ga-DOTATATE PET-CT and MRI in addition to widespread metastatic skeletal lesions, and metastatic lymph nodal disease. His symptoms worsened despite radiotherapy to left eye (20Gy) and long-acting octreotide therapy for 18 months, with increase in serum chromogranin A (CgA) level and was considered for ¹⁷⁷Lutetium(Lu)-DOTATATE peptide receptor radionuclide therapy (PRRT). Results: There was significant improvement in skeletal pain, proptosis and vision after 4 cycles of PRRT (cumulative dose of 22.2GBq), stable disease on scan and decrease in serum CgA (from 150 to 36.39 ng/ml) with progression free survival at 18 months. Conclusion: PRRT through theranostic application of ⁶⁸Ga/¹⁷⁷Lu-DOTATATE was thus helpful in this uncommon clinical setting.