Utility of Gallium-68-DOTATATE PET CT in Surveillance of Resected Gastroenteropancreatic NET.

Background/

Objectives

For completely resected well differentiated (WD) gastroenteropancreatic (GEP) NET, guidelines differ in recommendations for utilization of SSTR-based functional imaging in post-operative surveillance. While 111In-Octreotide has previously been the standard of care, imaging with 68Ga-labelled peptides has expanded in recent years due to increased sensitivity to detect smaller volume diseases and reduced costs. Though many centres have widely adopted imaging with 68Ga-labelled peptides, its role in surveillance of resected GEP NET has not been well defined. We sought to characterize current utilization of imaging with 68Ga-DOTATATE PET CT (68Ga-DOTA) for post-operative surveillance of WD GEP NET and assess the impact on clinical management.

Methods

We conducted a retrospective review of all 68Ga-DOTA scans performed from April 2019 to August 2024. Inclusion criteria were age ≥ 18 years with WD grade 1 and 2 GEP NET that had undergone curative-intent surgery, had Stage I-III disease at diagnosis, and had 68Ga-DOTA post-operatively.

Results

Forty-six scans met the inclusion criteria. We identified four indications for 68Ga-DOTA: (1) post-operative assessment (n = 12); (2) routine surveillance (n = 18); (3) recurrence suspected based on cross-sectional imaging (n = 10); and (4) recurrence suspected based on biochemical monitoring (n = 6). Avidity for each indication was observed in 45%, 8%, 50%, and 80%, respectively. Initiation of long-acting somatostatin analogue was the most common management following avidity.

Conclusions

68Ga-DOTA best informed clinical decision making when there was clinical suspicion for residual or metastatic disease post-operatively or based on cross-sectional imaging or biochemistry. The utility of this modality for routine surveillance appears limited.