ABSTRACT

In well differentiated thyroid cancers, FDG PET has a relatively low sensitivity. F-18 FDG PET/CT is an imaging method which is used before the treatment and in high risk patient groups with suspected recurrent disease. In this study we aim to determine the character of metabolic activity in differentiated thyroid cancer and in case of metastasis and to evaluate the findings of F-18-FDG PET/CT images in high risk patient group of differentiated thyroid cancer.

The data of 79 patients who underwent imaging for staging or restaging and followed at Trakya Univer ¬sity Faculty of Medicine from 2010 to 2015, were included in this study. Patient reports were analyzed retrospectively. Age, gender, size of thyroid lesion, presence of lymphadenopathy, other organ metastases (lung, liver, brain, bone) were included in the study.

The findings of 79 patients (29 male, 50 female) with papillary differentiated thyroid cancer were included in the analyses. The mean age of participants was 51±15 years. 14 patients (18%) were evaluated as normally. Recur¬- rent disease was detected in the thyroid gland of 10 patients (13%) (SUVmax: 6.2±5.1; 2.3-19.3). In 54 patients (68%) lymph node metastasis was detected (SUVmax; 5.8±5.1; 2.1-24.2). 12 patients had liver metastasis (SUVmax: 5.7±3.9; 2.0-11.7), 12 patients had bone metastasis (SUVmax: 6.1±2.9; 2.2-13.9), 8 patients had lung metastasis (SUVmax: 4.3±4.5; 1.0-4.9) and one patient had brain metastasis (SUVmax: 10.2).

Papillary differentiated thyroid cancer is associated with a tumor showing low glucose affinity, but it is understood that the tumor changes its behavior and gets metabolically active in the patients within the high risk group and in those with systemic metastasis.

Keywords: Thyroid cancer, F-18 FDG, PET/CT