Predictive Value of 18F-FDG PET in Patients with Advanced Medullary Thyroid Carcinoma Treated with Vandetanib

J Nucl Med. 2018 May;59(5):756-761. doi: 10.2967/jnumed.117.199778. Epub 2017 Oct 12.

Abstract

Therapeutic options in advanced medullary thyroid carcinoma (MTC) have markedly improved since the introduction of tyrosine kinase inhibitors (TKIs). We aimed to assess the role of metabolic imaging using 18F-FDG PET/CT shortly before and 3 mo after initiation of TKI treatment. Methods: Eighteen patients with advanced and progressive MTC scheduled for vandetanib treatment underwent baseline 18F-FDG PET/CT before and 3 mo after TKI treatment initiation. During follow-up, CT scans were obtained every 3 mo and analyzed according to RECIST. The predictive value for estimating progression-free survival (PFS) and overall survival (OS) was examined by investigating the 18F-FDG SUVmean/max of the metabolically most active lesion, as well as by analyzing clinical parameters (tumor marker doubling times [calcitonin, carcinoembryonic antigen], prior therapies, rearranged-during-transfection mutational status, and disease type). Results: Within a median follow-up of 5.2 y, 9 patients experienced disease progression after a median interval of 2.1 y, whereas the remainder had ongoing disease control (5 with a partial response and 4 with stable disease). Eight of the 9 patients with progressive disease died from MTC after a median of 3.5 y after TKI initiation. A pretherapeutic SUVmean of more than 4.0 predicted a significantly shorter PFS (1.9 y vs. 5.2 y, P = 0.04). Furthermore, sustained high 18F-FDG uptake at 3 mo with a SUVmean of more than 2.8 tended to portend an unfavorable prognosis, with a PFS of 1.9 y (vs. 3.5 y, P = 0.3). Prolonged carcinoembryonic antigen doubling times were significantly correlated with longer PFS (r = 0.7) and OS (r = 0.76, P < 0.01). None of the other clinical parameters had prognostic significance. Conclusion: Pretherapeutic 18F-FDG PET/CT provides prognostic information in patients with advanced MTC scheduled for treatment with the TKI vandetanib. A low tumor metabolism with an SUVmean of less than 4.0 before treatment predicts a longer PFS.

Keywords: 18F-FDG; 2-deoxy-2-(18F)fluoro-d-glucose; medullary thyroid carcinoma; positron emission tomography; tyrosine kinase inhibitor; vandetanib.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoembryonic Antigen / analysis
  • Carcinoma, Neuroendocrine / diagnostic imaging*
  • Carcinoma, Neuroendocrine / drug therapy*
  • DNA Mutational Analysis
  • Disease Progression
  • Disease-Free Survival
  • Female
  • Fluorodeoxyglucose F18
  • Follow-Up Studies
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Middle Aged
  • Piperidines / therapeutic use*
  • Positron Emission Tomography Computed Tomography*
  • Predictive Value of Tests
  • Prognosis
  • Quinazolines / therapeutic use*
  • Thyroid Neoplasms / diagnostic imaging*
  • Thyroid Neoplasms / drug therapy*
  • Treatment Outcome

Substances

  • Carcinoembryonic Antigen
  • Piperidines
  • Quinazolines
  • Fluorodeoxyglucose F18
  • vandetanib

Supplementary concepts

  • Thyroid cancer, medullary