Role of 18F-FDG PET/CT in detection of post-thyroidectomy recurrence in differentiated cancer thyroid with negative radio-isotope iodine scan and elevated serum thyroglobulin level

Congress:

ECR 2020

Poster Number:

C-07318

Type:

Educational Exhibit

Keywords:

Performed at one institution, Diagnostic or prognostic study, Prospective, Metastases, Cancer, Diagnostic procedure, Comparative studies, PET-CT, Thyroid / Parathyroids, Hybrid Imaging, Hybrid, Molecular and Translational Imaging

Authors:

A. A. M. M. S. khalifa¹, S. M. I. Y. Shalaby², M. Ali¹, A. Mostafa¹, A. Ibrahim¹, A. Yassin³; ¹Cairo/EG, ²Cairo, Ca/EG, ³cairo, cairo/EG

DOI:

10.26044/ecr2020/C-07318

DOI-Link:

https://dx.doi.org/10.26044/ecr2020/C-07318

Learning objectives

Demonstrating the role of 18F-FDG PET/CT for detection of post-thyroidectomy recurrence in differentiated cancer thyroid patients who presented with elevated serum thyroglobulin level, yet showing negative radio-isotope iodine scan.

Background

Thyroid cancer is a common disease nowadays and accounts for approximately 1% of all cancer cases (1). Differentiated thyroid cancer is generally characterized by long term survival, good prognosis and low aggressiveness (2). Most people diagnosed with thyroid cancer undergo total thyroidectomy followed by radio-active iodine ablation (3). The Thyroglobulin is primarily used as a tumor marker to evaluate the effectiveness of treatment for thyroid cancer and to monitor for recurrence (4). I (131) whole body scan has been at the center of recurrent thyroid...

Findings and procedure details

Procedure: This is a prospective study which included 20 patients who were under follow up at nuclear medicine and PET/CT unit in Nasser oncology center during the period from July 2017 to July 2019. Patients met the following inclusion criteria: Histopathologically proved differentiated thyroid carcinoma. Total radio-surgical thyroid ablation. Elevated serum Thyroglobulin levels (> 10ng/ml in patients with stimulated TSH level and >1ng/ml in patients with suppressed TSH level). Negative I(131)whole body scan. Exclusion criteria were as follow: Thyroglobulin level (

Conclusion

Discussion The differentiated thyroid cancer cells after total thyroidectomy & radioiodine ablation may undergo a process of transformation thus losing some or all their ability to take up & retain iodine, but they still retain the ability to absorb FDG(6). The role of FDG PET/CT in differentiated thyroid cancer is well established, particularly in patients presenting with elevated Thyroglobulin levels and negative radioactive iodine whole body scan. The uptake of FDG is related to tumor size, thyroid capsule invasion and histological variants with poor prognosis...

Personal information and conflict of interest

Ahmed S. Khalifa; Cairo/EG - Speaker at Saudi German hospital Cairo - Sherif Mohsen Shalaby; Cairo, CA/EG - Radiologist at Dar Elfouad Hospital cairo A. Mostafa; Cairo/EG - Consultant at Ain shams university A. Yassin; Cairo, CAIRO/EG - Consultant at Ain Shams University A. Ibrahim; Cairo/EG - Consultant at Ain Shams University M. Ali; Cairo/EG - at Saudi German hospital Cairo

References

1- Lin F & Iagaru A( 2016): Updates on PET/CT & thyroid cancerRadiology, 28:8-12. 2- Bertagna F, Biasiotto G, Orlando E et al. (2017): Role of F-18 FDG PET/CT in patients affected by differentiated thyroid cancer with high thyroglobulin level & negative I-131 scan. Japn J Radiol., 28: 629- 636. 3- Hamed M, Abdelghany A ,Osman A( 2014):The diagnostic usefulness of FDG-PET/CT in detecting tumor recurrence not evident in whole body I131 scan in differentiated thyroid carcinoma.The Egyptian journal of radiology & nuclear medina, 25:...