Clinical relevance of F-18 -FDG PET/CT in the follow-up of patients with operated medullary thyroid cancer. Is there any additional value of other radionuclide methods?

FDG PET/CT in medullary cancer

Abstract

Objective: The aim is evaluation of ¹⁸F-FDG PET/CT in the detection of active disease in the patients with suspected recurrence of the medullary thyroid carcinoma (MTC).

Methods: ¹⁸F-FDG PET/CT investigation was performed in 67 patients. Additionally, 25 underwent ^99mTc-DMSA scintigraphy, 11 underwent somatostatin receptor scintigraphy (SRS) with ^99mTc- HYNIC TOC while 11 ¹²³I-MIBG scintigraphy.

Results: From 67 patients, 35 (52.2%) had true positive ¹⁸F-FDG PET/CT findings (TP). Average standardized uptake value (SUVmax) for all TP lesions was 5.01 + 3.6. In 25 (37.3%) patients findings were true negative  (TN). Four (6%) patients had false positive (FP) findings while three (4.5%) were false negative (FN). Thus, sensitivity of the ¹⁸F-FDG PET/CT was 92.11%, specificity 86.21%, positive predictive value 89.74%, negative predictive value 89.29% and accuracy 89.55%.  In 27 patients (40%) ¹⁸F-FDG PET/CT finding influenced further management of the patient. 

Conclusion: ¹⁸F-FDG PET/CT has high accuracy in the detection of metastases/recurrences of MTC in patients after thyroidectomy as well as in evaluation and the appropriate choice of the therapy.