Metastatic Medullary Thyroid Cancer: The Role of 68Gallium-DOTA-Somatostatin Analogue PET/CT and Peptide Receptor Radionuclide Therapy

J Clin Endocrinol Metab. 2021 Nov 19;106(12):e4903-e4916. doi: 10.1210/clinem/dgab588.


Context: Metastatic medullary thyroid cancer (MTC) is a rare malignancy with minimal treatment options. Many, but not all, MTCs express somatostatin receptors.

Objective: Our aim was to explore the role of 68Ga-DOTA-somatostatin analogue (SSA) positron emission tomography (PET)/computed tomography (CT) in patients with metastatic MTC and to determine their eligibility for peptide receptor radionuclide therapy (PRRT).

Methods: We retrospectively identified patients with metastatic MTC who had 68Ga-DOTA-SSA PET/CT at 5 centers. We collected characteristics on contrast-enhanced CT, 68Ga-DOTA-SSA and 18F-FDG PET/CT. The efficacy of PRRT was explored in a subgroup of patients. Kaplan-Meier analysis was used to estimate time to treatment failure (TTF) and overall survival (OS).

Results: Seventy-one patients were included (10 local recurrence, 61 distant disease). Of the patients with distant disease, 16 (26%) had ≥50% of disease sites with tracer avidity greater than background liver, including 10 (10/61, 16%) with >90%. In 19 patients with contemporaneous contrast-enhanced CT, no disease regions were independently identified on 68Ga-DOTA-SSA PET/CT. Thirty-five patients had an 18F-FDG PET/CT, with 18F-FDG positive/68Ga-DOTA-SSA negative metastases identified in 15 (43%). Twenty-one patients had PRRT with a median TTF of 14 months (95% CI 8-25) and a median OS of 63 months (95% CI 21-not reached). Of the entire cohort, the median OS was 323 months (95% CI 152-not reached). Predictors of poorer OS included a short calcitonin doubling-time (≤24 months), strong 18F-FDG avidity, and age ≥60 years.

Conclusions: The prevalence of high tumor avidity on 68Ga-DOTA-SSA PET/CT is low in the setting of metastatic MTC; nevertheless, PRRT may still be a viable treatment option in select patients.

Keywords: 68Gallium-DOTATATE PET; 18F-FDG PET; PRRT; medullary thyroid cancer; peptide receptor radionuclide therapy; somatostatin receptors.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Neuroendocrine / diagnostic imaging
  • Carcinoma, Neuroendocrine / radiotherapy*
  • Carcinoma, Neuroendocrine / secondary
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Organometallic Compounds / therapeutic use*
  • Positron Emission Tomography Computed Tomography / methods*
  • Prognosis
  • Receptors, Peptide / therapeutic use*
  • Receptors, Somatostatin / therapeutic use*
  • Retrospective Studies
  • Somatostatin / chemistry*
  • Survival Rate
  • Thyroid Neoplasms / diagnostic imaging
  • Thyroid Neoplasms / radiotherapy*
  • Thyroid Neoplasms / secondary
  • Young Adult


  • Organometallic Compounds
  • Receptors, Peptide
  • Receptors, Somatostatin
  • Somatostatin
  • gallium Ga 68 dotatate

Supplementary concepts

  • Thyroid cancer, medullary