Is SUVmax a useful marker for progression-free survival in patients with metastatic GEP-NET receiving ¹⁷⁷Lu-DOTATATE therapy?

Objective: The prognostic potential of pretreatment maximum standardized uptake volume (SUVmax) on gallium-68-DOTATATE was evaluated with positron emission tomography/computed tomography (Ga-68-DOTATATE PET/CT) in 37 patients with G1/G2 gastroenteropancreatic neuroendocrine tumors (NET) who received peptide receptor radionuclide therapy (PRRT) with lutetium-177-[DOTA degrees,Tyr3] octreotate (Lu-177-DOTATATE) after the failure of somatostatin analogues. Methods: The mean and total SUVmax were used in Ga-68-DOTATATE PET/CT before Lu-177-DOTATATE treatment to assess the progression-free survival (PFS). Results: The responses of the patients were evaluated as partial response in 8 (32%) patients, stable disease in 12 (48%), and progressive disease in 5 (20%). The median PFS was 18 months; longer than this threshold in 14 patients (26.0 months) and shorter in 11 (8.4 months). The mean SUVmax of metastases in the liver (34.15 +/- 17.89 vs. 14.69 +/- 9.17, P=0.004) and mean SUVmax of all body metastatic lesions (33.05 +/- 14.32 vs. 15.26 +/- 4.84, P=0.001) were higher in patients with longer PFS. The tumor grade, the origin of the tumor, Ki67 status, and previous somatostatin treatment history were not signicantly different between the two PFS groups. Conclusions: The pre-treatment SUVmax values of Ga-68-DOTATE PET/CT in lesions are a potential prognostic factor for PFS in well-differentiated gastroenteropancreatic neuroendocrine tumors undergoing Lu-177-DOTATATE treatment and could be a useful parameter for the treatment selection.