Comparison of Radioactive Iodine Activities in Terms of Short- and Long-term Results in Ablation Therapy in Patients with Low-risk Differentiated Thyroid Cancer.

Objectives: The aim of this study was to compare the treatment responses after ablation with 30-50 mCi radioactive iodine (RAI) and 100 mCi RAI in patients with differentiated thyroid cancer (DTC) who were in the low-risk group according to 2015 American Thyroid Associations Classification (ATA 2015) criteria. Methods: Between February 2016 and August 2018, 100 patients who received RAI treatment in our clinic after total thyroidectomy and who were in the low-risk group DTC were included in this retrospective study. These patients were divided into 2 groups: low-activity (30-50 mCi) (group 1) and high-activity (100 mCi) (group 2). While 54 patients were treated with low activity, 46 patients received high activity RAI. The 2 groups were compared according to the 1st- and 3rd-year treatment response status. Results: According to the first-year follow-up, 15 patients were accepted as indeterminate response and 85 patients as excellent response. Three (5.5%) of the patients who were accepted as indeterminate response were in group 1 and 12 (26%) were in group 2. According to the third year follow-up, 1 patient in group 1 and 3 patients in group 2 were accepted as indeterminate response. No biochemical incomplete response or recurrent disease was detected. In the chi-square analysis performed to investigate the relationship between the first-year treatment response and RAI activities, a significant relationship was found (p=0.004). In the Mann-Whitney U test performed to investigate the parameters that may be effective in the treatment response, only the preablative serum thyroglobulin value was shown to have a significant difference between the two groups (p=0.01). In the long-term follow-up of the patients, based on the third year treatment response data, chi-square analysis was performed to evaluate the two groups in terms of treatment responses, and no statistically significant relationship was found (p=0.73). Conclusion: Ablation with 30-50 mCi can be safely applied in DTC patients who are in the ATA 2015 low-risk group and are planned for RAI ablation treatment.

The Predictive Value of Proportional Evaluation Based on the Metabolic Activity of Cervical Lymph Nodes on PET/CT Imaging in Patients with Larynx Cancer.

OBJECTIVES: We aimed to evaluate the proportional values of maximum standardized uptake value (SUVmax) for cervical lymph nodes on 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for prediction of the presence of metastasis in patients with larynx squamous cell cancer (LSCC). METHODS: This retrospective study involved 43 patients with LSCC. All patients underwent resection of the primary tumor and neck dissection within 4 weeks after undergoing 18F-FDG PET/CT examinations. Receiver operating characteristic (ROC) analysis was performed to evaluate the lymph node SUVmax/primary tumor SUVmax (SUVmaxLN/SUVmaxPT), lymph node SUVmax/aortic SUVmax (SUVmaxLN/SUVmaxA), and lymph node SUVmax/ liver SUVmax (SUVmaxLN/SUVmaxL) ratios for diagnosis of lymph node metastasis. RESULTS: SUVmaxLN/SUVmaxA, SUVmaxLN/SUVmaxL, and SUVmaxLN/SUVmaxPT rates were significantly higher in metastatic lymph nodes compared to non-metastatic nodes. ROC analysis for metastasis showed that the cut-off thresholds were 3.87 for SUVmaxLN; 1.78 for SUVmaxLN /SUVmaxA; 1.08 for SUVmaxLN/SUVmaxL; and 0.36 for SUVmaxLN/SUVmaxPT. The diagnostic sensitivity, specificity and AUC were 83.7%, 77%, 0.856 for SUVmaxLN; 79.7%, 84%, 1.78 for SUVmaxLN/SUVmaxA; 84.1%, 76%, 0.833 for SUVmaxLN/SUVmaxL; and 53.6%, 76%, 0.666 for SUVmaxLN/SUVmaxPT, respectively. CONCLUSION: SUVmaxLN/SUVmaxA, SUVmaxLN/SUVmaxL, and SUVmaxLN/SUVmaxPT ratios can be safely used for diagnosis of cervical lymph node metastasis in patients with LSCC.

Ileal Neuroendocrin Tumor Metastasis to Breast Diagnosed with Ga-68 DOTATATE PET/CT

Breast metastasis of the well differentiated neuroendocrin tumor (WDNET) of the ileum is very rare. A case of a 62-year-old woman with ileal WDNET, who underwent restaging with Ga-68 DOTATATE PET/CT due to progression of metastatic lesions under the treatment with somatostatin analog and mammalian target of rapamycin inhibitors. Ga-68 DOTATATE PET/CT demonstrated intense increased uptake in the subsantimetric nodular lesion in the upper outer quadrant of the left breast. The histopathologic findings obtained by tru-cut biopsy revealed WDNET metastasis (Ki-67 proliferation index 1%).