Comparison of the Impact of 68Ga-DOTATATE and 18F-FDG PET/CT on Clinical Management in Patients with Neuroendocrine Tumors

J Nucl Med. 2017 Jan;58(1):91-96. doi: 10.2967/jnumed.116.178095. Epub 2016 Aug 11.


This study aimed to assess the clinical impact of 68Ga-DOTATATE and 18F-FDG with respect to the management plan and to evaluate the prognostic value of both tracers.

Methods: A total of 104 patients (55 male and 49 female; median age, 58 y; range, 20-90 y) with histologically proven neuroendocrine tumors (NETs) underwent both 68Ga-DOTATATE and 18F-FDG PET/CT. Twenty-eight patients (26.9%) had poorly differentiated tumors, and 76 (73.1%) had well-differentiated tumors. PET/CT results and SUVs were compared with prognostic factors such as histologic grade (G1, G2, or G3, for low-grade [well differentiated], intermediate-grade [moderately differentiated], and high-grade [poorly differentiated], respectively), chromogranin A, and proliferation index (Ki-67).

Results: The 68Ga-DOTATATE and 18F-FDG PET/CT findings were discordant in 65 patients (62.5%) and concordant in 39 patients (37.5%). The results changed the therapeutic plan in 84 patients (80.8%). In 22 patients (21.1%), decision making was based on the 18F-FDG findings; in 32 (30.8%), on the findings with both radiotracers; and in 50 (48.1%), on the 68Ga-DOTATATE findings. The most frequent management decision based on 18F-FDG was initiation of chemotherapy (10 patients, 47.6%). The most common treatment decision due to 68Ga-DOTATATE was initiation of peptide receptor radionuclide therapy (14 patients, 27.4%). In 11 (39.2%) of 28 patients with poorly differentiated NETs, the management decision was based on only the 18F-FDG results. For 68Ga-DOTATATE, SUVmax was higher for G1 tumors and lower for G3 tumors (P = 0.012). However, no significant differences in 18F-FDG-derived SUVs were observed between different grades (P = 0.38). The Mann-Whitney test showed significant differences in 68Ga-DOTATATE SUVmax between tumors with a Ki-67 of less than 5% and tumors with a Ki-67 of more than 5% (P = 0.004), without significance differences in 18F-FDG SUVmax Log-rank analysis showed statistically significant differences in survival for patients with bone metastasis versus soft-tissue or no metastasis for both 18F-FDG (P = 0.037) and 68Ga-DOTATATE (P = 0.047). Overall survival declined rapidly with increasing grade (P = 0.001), at an estimated 91 mo for G1, 59 mo for G2, and 48 mo for G3.

Conclusion: 18F-FDG PET/CT had no clinical impact on G1 NETs and a moderate impact on G2 NETs. However, in poorly differentiated NETs, 18F-FDG PET/CT plays a significant clinical role in combination with 68Ga-DOTATATE. 68Ga DOTATATE SUVmax relates to grade and Ki-67 and can be used prognostically.

Keywords: 18F-FDG PET/CT; 68Ga-DOTATATE; clinical impact; neuroendocrine tumors; prognosis.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Fluorodeoxyglucose F18*
  • Humans
  • Male
  • Middle Aged
  • Neuroendocrine Tumors / diagnostic imaging*
  • Neuroendocrine Tumors / epidemiology
  • Neuroendocrine Tumors / therapy*
  • Organometallic Compounds*
  • Patient Care Management / statistics & numerical data*
  • Positron Emission Tomography Computed Tomography / methods*
  • Prevalence
  • Prognosis
  • Radiopharmaceuticals
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity
  • Treatment Outcome
  • United Kingdom / epidemiology


  • Organometallic Compounds
  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18
  • gallium Ga 68 dotatate