The value of preoperative PET-CT in papillary thyroid cancer

Abstract

Objective: To evaluate the clinical usefulness of preoperative positron emission tomography-computed tomography (PET-CT) in primary papillary thyroid cancer (PTC). Methods: Preoperative PET-CT scans of patients with biopsy-confirmed PTC who were undergoing thyroidectomy were examined and the maximum standardized uptake value (SUVmax) of 2-deoxy-2-(F-18) fluoro-D-glucose (F-18-FDG) was calculated. Demographic and clinical data were obtained from medical records. Tumour tissue was pathologically classified according to World Health Organization guidelines. Univariate and multivariate analyses were performed to determined the demographic, clinical and pathological factors affecting PET positivity and SUVmax. Results: The study included 194 patients. Multivariate analysis indicated that patients were significantly more likely to be PET positive if they were female, had larger tumours (>1 cm), coexisting pathology (nodular hyperplasia or Hashimoto's thyroiditis) or nonfollicular variant PTC. SUVmax <2.0 indicated possible follicular variant PTC. Conclusions: PET-positive results were unrelated to extrathyroidal extension and lymph node metastasis. PET positivity was related to larger tumour size and implied coexisting pathology. PET negativity or low SUVmax suggested possible follicular variant PTC.