[18F]FDG-PET/CT and long-term responses to everolimus in advanced neuroendocrine neoplasia

J Endocrinol Invest. 2021 Apr;44(4):811-818. doi: 10.1007/s40618-020-01378-3. Epub 2020 Aug 7.


Purpose: This study aims to identify in patients with neuroendocrine neoplasia (NEN) the potential correlation between FDG-PET findings and responses to everolimus therapy to identify predictors of long-term efficacy.

Methods: Retrospective analysis of patients with sporadic, advanced, progressive NEN treated with everolimus was performed based on the available data on FDG-PET patients obtained before commencing therapy. Data are expressed as the median (25-75th IQR). Risk factor analysis and survival analysis were performed by logistic regression and Cox proportional hazard regression and the determination of Kaplan-Meier curves, as appropriate.

Results: Sixty-six patients were evaluated (NET G1 19.7%, NET G2 75.7%, and NET G3 4.6%), including 45.4% with positive FDG-PET findings. Overall, disease stabilization and a partial response were achieved for 71.2% and 6% of patients, respectively. A long-term response (> 24 months) was observed in 33% of patients. Ki67 was the only predictor of tumor progression (p = 0.03). No significant difference in clinical outcomes was observed between patients with positive or negative FDG-PET findings (median PFS was 24 months and 18 months, respectively, p = 0.337; the disease control rate was 83.3% and 70%, respectively, p = 0.245).

Conclusions: Everolimus is a valid therapeutic option for advanced, progressive, well-differentiated NEN, even in patients with positive FDG-PET findings.

Keywords: 18F-fluorodeoxyglucose PET/CT; Everolimus; Ki67; Long-term response; Neuroendocrine neoplasia; Tumor progression.

MeSH terms

  • Antineoplastic Agents / administration & dosage
  • Antineoplastic Agents / adverse effects
  • Disease Progression
  • Drug Monitoring / methods*
  • Everolimus* / administration & dosage
  • Everolimus* / adverse effects
  • Female
  • Humans
  • Italy / epidemiology
  • Kaplan-Meier Estimate
  • Ki-67 Antigen / analysis*
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Neuroendocrine Tumors* / drug therapy
  • Neuroendocrine Tumors* / mortality
  • Neuroendocrine Tumors* / pathology
  • Positron Emission Tomography Computed Tomography / methods*
  • Predictive Value of Tests
  • Proportional Hazards Models
  • Retrospective Studies
  • Time


  • Antineoplastic Agents
  • Ki-67 Antigen
  • MKI67 protein, human
  • Everolimus