Long-Term Survival and Value of F-FDG PET/CT in Patients with Gastroenteropancreatic Neuroendocrine Tumors Treated with Second Peptide Receptor Radionuclide Therapy Course with Lu-DOTATATE.

Peptide receptor radionuclide therapy (PRRT) has been recognized as a promising therapy against neuroendocrine tumors (NETs). The use of F-fluorodeoxyglucose (F-FDG) positron emission tomography (PET) in NETs has been a matter of controversy. The purpose of this study was to evaluate the long-term survival and efficacy of a second PRRT course with Lu-DOTATE in patients with advanced gastroenteropancreatic (GEP) NETs. Furthermore, the value of F-FDG PET/CT in these patients was evaluated. 40 patients with GEP NETs who underwent two PRRT courses with Lu-DOTATATE and combined examinations with Ga-DOTA-TOC and F-FDG PET/CT were evaluated. After the second PRRT course, two patients (5.0%) were in partial remission, 21 patients (52.5%) in stable disease and 17 patients (42.5%) had progressive disease. The median overall survival was 122.10 months. After the second PRRT course, the median overall survival was significantly higher ( = 0.033) in the F-FDG-negative group compared to the F-FDG-positive group (145.50 versus 95.06 months, respectively). The median time to progression was 19.37 months. In conclusion, a second PRRT course with Lu-DOTATE is an effective treatment approach for GEP NET patients with disease progression. A change in F-FDG status after PRRT may predict the disease course and survival. Patients who are F-FDG-negative have a significantly longer overall survival than those who are F-FDG-positive.