E4864. Assessing the Treatment Response to 177Lutetium-DOTATATE Therapy for Patients With Advanced Metastatic Neuroendocrine Tumors
Authors
Ziyu Xian;
Baystate Medical Center; University of Massachusetts Chan - Baystate
Jennifer Wu;
Baystate Medical Center; University of Massachusetts Chan - Baystate
Sideris Georgios;
Baystate Medical Center; University of Massachusetts Chan - Baystate
Njogu Njuguna;
Baystate Medical Center; University of Massachusetts Chan - Baystate
Christopher Mudge;
Baystate Medical Center; University of Massachusetts Chan - Baystate
Priyanka Deb;
Baystate Medical Center; University of Massachusetts Chan - Baystate
Edison Tsui;
No Affiliation
Background
Neuroendocrine tumors (NETs) arise from neuroendocrine cells, with the majority being nonfunctional (i.e., nonhormone secreting). They are frequently metastatic at initial presentation, and the 5-year survival rate is less than 50% despite advances in treatments. Lutetium-177-DOTATATE was approved by the FDA in 2018. It is a beta- and gamma-emitting radionuclide that binds to somatostatin receptors, allowing for focused delivery of high-dose radiation directly to NETs. Treatment consists of one IV injection every 8 weeks for a total of four cycles, along with long-acting octreotide intramuscularly. Initial clinical trials showed promising results in terms of progression free survival, and a trend toward overall survival. However, the real-world evidence has yet to be assessed since its implementation.
Educational Goals / Teaching Points
This exhibit aims to examine the real-world clinical outcomes in patients who completed 177Lu-DOTATATE therapy.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
A total of 15 patients (8 men and 7 women) with well-differentiated NETs were included. The ages ranged from 55–81 years old. Eleven patients had midgut NET, two had pancreatic NET, and one had atypical carcinoid of the thymus. All patients had radiographic evidence of disease progression with first-line somatostatin analogue therapy and subsequently completed four cycles of 177Lu-DOTATATE. The size of their metastatic lesions based on pre- and posttreatment imaging with CT was assessed using the revised RECIST criteria to determine treatment response. Interval imaging performed within 6 months posttreatment showed a partial response in four patients, and stable disease in eight patients. Within those eight patients, three had stable disease beyond 12 months. The patient with atypical carcinoid of the thymus and one patient with pancreatic NET showed disease progression with enlarging lesions and new metastasis. All patients tolerated the four cycles of treatment without significant treatment-related adverse effects.
Conclusion
In our cohort, 177Lu-DOTATATE is an effective therapy to halt disease progression in patients with well-differentiated NETs. However, the efficacy may be limited to well-differentiated NETs of the midgut. Despite the small sample size, this study suggests the real-world clinical efficacy and tolerability of 177Lu-DOTATATE. Overall, 177Lu-DOTATATE was an excellent palliative option for midgut NETs in our patient cohort.
