Role of [(18)F]-fluorodeoxy-D-glucose positron emission tomography and computed tomography in the early detection of persistent/recurrent thyroid carcinoma in intermediate-to-high risk patients following initial radioactive iodine ablation therapy.

Abstract

BACKGROUND:

Positron emission tomography/computed tomography (PET/CT) scan has a role in the surveillance of patients with a history of thyroid carcinoma. Its efficacy after remnant ablation as far as detecting persistent or recurrent thyroid carcinoma before other surveillance methods is not known, however. In intermediate-to-high risk thyroid carcinoma patients we studied whether PET/CT scan, performed 6-12 months after the first remnant ablation, could provide more information than ultrasonography (US) and thyrotropin-stimulated serum thyroglobulin (Tg) determination with diagnostic whole-body scan (DxWBS).

METHODS:

We studied 71 subjects with differentiated thyroid cancer (DTC) who were intermediate-to-high risk for persistent/recurrent disease and who had received PET/CT scan, US, and DxWBS simultaneously with stimulated Tg levels 6-12 months after remnant ablation. To evaluate the diagnostic efficacy of PET/CT scan, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated.

RESULTS:

Ten subjects (14%) had persistent/recurrent disease detected 6-12 months after remnant ablation. Persistence/recurrence was detected in nine (12.7%) of these patients by conventional methods, including US and DxWBS, along with stimulated Tg levels. The remaining case was detected solely by a PET/CT scan, which showed a mediastinal prevascular lesion; this was confirmed by a therapeutic WBS after additional radioiodine therapy. Among the six patients whose PET/CT scan showed positive results, five had persistent/recurrent disease. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of PET/CT scan for detecting persistent/recurrent thyroid carcinoma were 50%, 98.4%, 83.3%, 92.3%, and 91.5%, respectively.

CONCLUSION:

In intermediate-to-high risk patients with DTC seen 6-12 months after their first remnant ablation, there is almost no complementary role for adding a PET/CT scan to conventional follow-up methods, an US and a DxWBS simultaneously with stimulated Tg levels.

• Authors: Min-Hee Kim, Joo Hyun O, Sun Hee Ko, Ja-Seong Bae, Dong-Jun Lim, Sung-Hoon Kim, Ki-Hyun Baek, Jong-Min Lee, Moo-Il Kang, Bong-Yun Cha, Kwang-Woo Lee
• Journal: Thyroid : official journal of the American Thyroid Association (Thyroid) Vol. 22 Issue 2 Pg. 157-64 (Feb 2012) ISSN: 1557-9077 [Electronic] United States
• PMID: 22224820 (Publication Type: Journal Article)

Chemical References

• Iodine Radioisotopes
• Fluorodeoxyglucose F18
• Thyroglobulin

Topics

• Adult
• Carcinoma (diagnosis, diagnostic imaging)
• Female
• Fluorodeoxyglucose F18
• Humans
• Iodine Radioisotopes (therapeutic use)
• Male
• Middle Aged
• Multimodal Imaging
• Neoplasm Recurrence, Local (diagnostic imaging)
• Positron-Emission Tomography
• Predictive Value of Tests
• Thyroglobulin (blood)
• Thyroid Neoplasms (diagnosis, diagnostic imaging)
• Tomography, X-Ray Computed
• Ultrasonography