Clinical Value of Visually Identifiable 18 F-fluorodeoxyglucose Uptake in Primary Papillary Thyroid Microcarcinoma

Abstract

Objective

This study evaluates the relationship between visually identifiable ¹⁸F-fluorodeoxyglucose (FDG) uptake in primary papillary thyroid microcarcinoma (PTMC) and tumor aggressiveness.

Study Design

Historical cohort study.

Setting

Tertiary care center.

Methods

Clinicopathological factors and PET/CT findings of 219 PTMC surgical patients who underwent preoperative ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) were retrospectively reviewed.

Results

¹⁸F-FDG uptake was observed in the tumors of 124 (56.6%) patients. Tumor size (odds ratio [OR] = 1.774; 95% confidence interval [CI], 1.416-2.223; P < .0001) and Hashimoto thyroiditis (OR = 2.815; CI, 1.237-6.404; P = .014) independently predicted ¹⁸F-FDG uptake. Tumor size (OR = 1.495; CI, 1.217-1.835; P < .0001) and BRAF^V600E mutation (OR = 3.320; CI, 1.056-10.432; P = .040) independently predicted extrathyroidal invasion. Multiplicity (OR = 2.375; CI, 1.278-4.415; P = .006) independently predicted central lymph node metastasis.

Conclusion

¹⁸F-FDG uptake in PTMC depends on tumor size and Hashimoto thyroiditis. Therefore, preoperative PET/CT for PTMC may not help in evaluating tumor aggressiveness.