18F-FDOPA PET/CT-Guided Radiofrequency Ablation of Liver Metastases from Neuroendocrine Tumours: Technical Note on a Preliminary Experience.

Abstract

To review our preliminary experience with 6-L-18F-fluorodihydroxyphenylalanine (18F-FDOPA) PET/CT-guided radiofrequency ablation (RFA) of liver metastases from neuroendocrine tumours (NETs). Three patients (mean age 51.3years; range 43-56) with gastro-entero pancreatic NET (GEP-NET) liver metastases underwent 18F-FDOPA PET/CT-guided RFA. Patients were referred with oligometastatic hepatic-confined disease (1-6 metastases; <3cm) on 18F-FDOPA PET/CT; poor lesion visualisation on US, CT, and MR; and ongoing symptoms. Procedures were performed in an interventional PET/CT scanner under general anaesthesia using a split-dose protocol. Lesion characteristics, procedural duration and technical success (accurate probe placement and post-procedural ablation-zone photopaenia), complications, patient and operator dose, and clinical outcomes were evaluated. Thirteen liver metastases (mean size 11.4mm, range 8-16) were treated in three patients (two presented with "carcinoid syndrome"). Technical success was 100% with a mean procedural duration of 173.3min (range 90-210) and no immediate complications. Mean patient dose was 2844mGy·cm (range 2104-3686). Operator and radiographer doses were acceptable other than the operator's right hand in the first case (149µSv); this normalised in the second case. There was no local tumour or extra-hepatic disease progression at mid-term follow-up (mean 12.6months; range 6-20); however, two cases progressed with new liver metastases at different sites. There was 100% clinical success (n=2) in resolving carcinoid syndrome symptoms. 18F-FDOPA PET/CT-guided RFA appears technically feasible, safe, and effective in patients with GEP-NETs and low-burden hepatic metastases. Further prospective studies are required to elucidate its precise role in tailored multimodality management of GEP-NET liver metastases.