ABSTRACT
Differentiated thyroid carcinomas (DTC) are the most common form of endocrine malignancies. The role of genetic variations in the development of papillary thyroid carcinoma (PTC) is approximately 60.0-70.0%. The X-ray repair cross-complementing group 1 (XRCC1) protein has an important role in DNA repair mechanisms and genomic polymorphisms of XRCC1 gene affect the function of the protein. In the present case-control study, we aimed to compare the genotype frequency distributions of XRCC1 single nucleotide polymorphisms (SNPs) in terms of the presence of other risk factors (Hashimoto's thyroiditis, smoking, obesity, radiation exposure) in patients with thyroid nodules who had fine-needle aspiration biopsy (FNAB) and/or thyroid surgery due to thyroid cancer. The genotype frequency distributions of three common XRCC1 SNPs (Arg194Trp, Arg399Gln, Arg280His) were compared to those with DTC (n = 228), benign thyroid nodules (BTN, n = 100) and healthy controls (n = 93) in terms of certain pre defined risk factors such as the presence of Hashimoto's thyroiditis, smoking, obesity, a family history of thyroid cancer and radiation exposure. The frequency of the GA genotype of Arg280His in DTC cases was found to be higher than in those with BTN and the healthy control group (p <0.001). The DTC group had the lowest frequency of AA genotype of Arg280His (35.5%, p <0.001). Among those with a family history of thyroid cancer, 78.9% had a GA genotype and 21.1% had the AA genotype of Arg280His (p = 0.004). The Arg280His GA genotype was more common in DTC than in cancer-free controls. The GA genotype frequency was also high in DTC cases with a family history of thyroid cancer.
ABSTRACT
AIMS: The objective of this study was to discuss the outcomes of the oncology patients whose PET/CT scans show incidental focal thyroid 18F-FDG uptake. METHODS: This retrospective analysis examined 2575 18F-FDG PET/CT scans from 1803 patients with no known thyroid cancer history. The survival rates were analyzed for patients with and without cytopathological evaluation. RESULTS: Increased metabolic activity of the thyroid was detected in 96 patients. Of those, 72 were diagnosed with a focal uptake of 18F-FDG and 24 subjects had a diffuse uptake. All 72 patients with a focal uptake were referred for ultrasound (US) and fine-needle aspiration cytology (FNAC). Of those patients, 44 were admitted for US and 16 underwent FNAC. The mean SUVmax was 16.0 ± 7.97 for patients with malignant lesions and 3.24 ± 0.88 for patients with benign lesions (p = 0.023). The mortality rate was higher in the patients who were not evaluated with FNAC. CONCLUSION: Patients with incidental focally increased thyroid 18F-FDG accumulation on PET/CT are known to have a high risk of malignancy. These patients require additional diagnostic procedures to distinguish the underlying pathology. However, the clinical condition of these patients will be the primary concern when performing these procedures.
