TY - JOUR ID - 708 TI - Both F-18 FDG-avidity and Malignant Shape of Cervical Lymph Nodes on PET/CT after Total Thyroidectomy Predict Resistance to High-dose I-131 Therapy in Patients with Papillary Thyroid Cancer JO - Asia Oceania Journal of Nuclear Medicine and Biology JA - AOJNMB LA - en SN - 2322-5718 AU - Byun, Byung Hyun AU - Kwon, Seong Young AU - Chong, Ari AU - Kim, Jahae AU - Yoo, Su Woong AU - Min, Jung-Joon AU - Song, Ho-Chun AU - Bom, Henry Hee-Seung AD - Department of Nuclear Medicine, Chonnam National University Hwasun Hospital, Hwasun, Jeollanam-do, Republic of Korea AD - Department of Nuclear Medicine, Chonnam National University Hospital, Gwangju, Republic of Korea Y1 - 2013 PY - 2013 VL - 1 IS - 1 SP - 6 EP - 13 KW - F-18 FDG PET/CT KW - resistance to I-131 therapy KW - cervical lymph node KW - Papillary thyroid cancer DO - 10.7508/aojnmb.2013.01.003 N2 - Objective(s): Resistance of metastatic lymph nodes (LNs) to high dose I-131 therapy is associated with high morbidity in patients with differentiated thyroid cancer. We evaluated the role of F-18 FDG PET/CT in the prediction of resistance to high dose I-131 therapy in patients with papillary thyroid cancer. Methods: The subjects were 307 patients who underwent total or near total thyroidectomy followed by high dose (5.55-6.66 GBq) I-131 therapy. We divided the patients into three subgroups by visual assessment of regional LNs: FDG-avid LNs with a malignant shape on CT (PET/CT-positive group), FDG-avid LNs with a benign shape on CT (PET/CT-intermediate group) and no FDG-avid lesion (PET/CT-negative group). We measured the maximum SUV (SUVmax) of FDG-avid LNs in each patient. The presence or absence of focal increased uptake of I-131 was evaluated by whole body scan (WBS), and was denoted as WBS-positive group or WBS-negative group, respectively. Resistance to therapy was defined as presence of thyroglobulin (Tg) in serum (Tg ≥1.0 ng/ml) 3-6 months after I-131 therapy. Univariate and multivariate analyses were performed to determine the relationship between resistance to I-131 therapy and various clinico-pathologic variables. Results: PET/CT-positive, intermediate, and negative groups included 20 (6.5%), 44 (14.3%) and 243 (79.2%) patients, respectively. The mean SUVmax was significantly higher in the PET/CT-positive group than that of the PET/CT-intermediate group (4.6 vs. 2.7, P <0.001). Univariate analysis revealed that the PET/CT-positive group (P <0.001), T2-4 stage (P <0.001), N1b stage (P = 0.001), lower dose (5.55 GBq) of I-131 (P <0.001), and the WBS-positive group (P = 0.029) were associated with resistance to therapy. In multivariate analysis, the PET/CT-positive group, lower dose of I-131, N1b stage, and T2-4 stage remained significant with odds ratios of 10.07 (P <0.001), 3.82 (P <0.001), 3.58 (P = 0.001), and 2.53 (P = 0.009), respectively. Conclusion: FDG-avidity and malignant shape of cervical LNs on pre-therapy FDG PET/CT were a strong risk factors predicting resistance to high dose I-131 therapy. A lower dose of administered I-131 (5.55 GBq) and more extensive tumors (T2-4 and N1b) were also associated with resistance to high dose I-131 therapy. UR - https://aojnmb.mums.ac.ir/article_708.html L1 - https://aojnmb.mums.ac.ir/article_708_38a13605336bbb7c506c6f650cbabaff.pdf ER -