Obesity is a risk factor for differentiated thyroid cancer (DTC), but the association with DTC aggressiveness is controversial. To evaluate the association between preoperative body mass index (BMI)/other metabolic parameters and DTC aggressiveness in our surgical cohort, we retrospectively evaluated patients following thyroid surgery who were diagnosed with DTC between December 2013 and January 2021. Baseline characteristics, histopathological features, treatment modalities, and follow-up data were studied. We conducted logistic regression to analyze the association between BMI/other metabolic parameters and adverse DTC features. The final study cohort included 211 patients (79.6% women; mean age± standard deviation 48.7 ± 15.9 years): 66 (31.3%) with normal weight, 81 (38.4%) with overweight, and 64 (30.3%) with obesity. The median follow-up was 51 months (range 7-93). Complete versus partial thyroidectomy was more common among patients living with overweight or obesity than in normal weight patients (79.7% versus 61.7%, p = 0.017, respectively). Logistic regression demonstrated that higher BMI was associated with mildly increased risk for lymph nodes metastases (odds ratio [OR] 1.077, 95% CI: 1.013-1.145), and higher triglycerides/high-density lipoprotein-cholesterol (TG/HDL-C) ratio was associated with aggressive histological variants of DTC (OR 1.269, 95% CI 1.001-1.61). To conclude, specific adverse clinical and histopathological DTC features were indeed associated with higher BMI and higher TG/HDL-C ratio.

The aim of this study was to establish the cut-off value for the thyroglobulin (Tg) concentration in washout fluid from fine needle aspiration biopsy (FNA-Tg) in the detection of cervical lymph node metastases of differentiated thyroid cancer (DTC). We evaluated the validity and clinical utility of fine needle aspiration biopsy cytology (FNAB-C), FNA-Tg, and the combined method in detecting DTC recurrences. The study included 82 patients after the total thyroidectomy and elective and, in some cases, also selective cervical lymphadenectomy. The majority of patients also underwent subsequent 131I ablative therapy. The patients presented with 1-6 enlarged and/or ultrasonographically suspicious cervical lymph nodes. One to four aspirates of each lymph node were taken, with a total of 297 samples. An FNA-Tg of 4.34 ng/mL was established as the cut-off value for detecting cervical lymph node DTC metastases for the IRMA Brahms DYNO test, Tg-S. FNAB-C is highly specific (91-99%) but not sensitive enough (53-69%) to be used as a standalone method in the detection of cervical lymph node metastases. FNA-Tg is more sensitive (91%), but caution should be taken when selecting patients for surgery with an FNA-Tg higher than the established cut-off value but lower than the serum Tg concentration. To select patients for lymphadenectomy, we recommend using the combined method (FNAB-C and FNA-Tg) with a sensitivity of 96% and specificity of up to 97%. More than one sample should be taken with each fine needle aspiration biopsy (FNAB) to obtain a representative set of samples.

The management guidelines of radioactive Iodine (RAI) therapy for distinct types of differentiated thyroid carcinoma (DTC) were the same in clinical practice. However, in distinct types DTC, differences in RAI avidity and response existed and the effect of RAI therapy could not be equated.
DTC patients\' data in SEER database were extracted to perform retrospective analysis. The differences between case group and control group were compared by chi-square tests. We used Kaplan-Meier statistics and Cox regression analyses to investigate cancer-specific survival (CSS). Propensity score-matched was performed to make 1:1 case-control matching.
105195 patients who receiving total thyroidectomy were identified in SEER database. Compared to papillary thyroid carcinoma (PTC) (52.3%), follicular thyroid carcinoma (FTC) (63.8%) and oncocytic carcinoma of thyroid (OCA) (64.4%) had higher rates of RAI therapy. In the multivariable Cox regression model, RAI therapy was independent prognosis factor in PTC but not in OCA and FTC. In subgroup analysis, RAI therapy could improve prognosis in PTC when gross extrathyroidal extension or lymph node metastases or early survival when distant metastases (DM) were presented. However, OCA and FTC patients with DM rather than regional lesions only could benefit from RAI therapy. High-risk patients receiving RAI therapy showed a better prognosis in PTC but not in OCA and FTC.
RAI therapy was an effective treatment for DTC and should be considered individually in PTC, OCA and FTC patients. Our results provided further guideline for treatment selection in DTC.

Residual/recurrent lymph node metastase (LNM) is often found after differentiated thyroid cancer (DTC) surgery. This study aimed to investigate whether patients complicated with radioiodine-avid (131I+) lymph nodes from DTC on the initial posttherapy scan (PTS) need repeated 131I therapy.
From June 2013 to August 2022, DTC patients with 131I+ lymph nodes on the initial PTS who received at least two cycles of 131I therapy were retrospectively enrolled. They were divided into a complete response (CR) group and an incomplete response (IR) group according to their response to the initial 131I therapy based on the 2015 American Thyroid Association (ATA) guidelines.
A total of 170 DTC patients with 131I+ lymph nodes on the initial PTS were included; 42/170 (24.7%) patients were classified into the CR group and 128/170 (75.9%) were classified into the IR group according to their response to the initial 131I therapy. None of the 42 CR patients had disease progression at the subsequent follow-up, and 37/170 (21.8%) IR patients improved after repeated therapy. Univariate analysis showed that N stage (P=0.002), stimulated thyroglobulin (sTg) level before initial 131I therapy (P<0.001), LNM size (P<0.001), number of total residual/recurrent LNM (P=0.021), radioiodine-nonavid (131I-) LNM (P=0.002) and ultrasound features (P<0.001) were related to the initial treatment response. On multivariate analysis, sTg level (OR=1.186, P<0.001) and LNM size (OR=1.533, P=0.004) were independent risk factors for IR after initial 131I therapy. The optimal sTg level and LNM size cutoff value for predicting the treatment response after initial 131I therapy were 18.2 µg/l and 5mm.
This study suggested that approximately one-quarter of patients with 131I+ lymph nodes on initial PTS, especially those with N0 or N1a stage, lower sTg level, smaller LNM size, ≤2 residual/recurrent LNMs, negative ultrasound features and no 131I- LNM, remain stable after one cycle of 131I therapy and do not need repeated therapy.

UNASSIGNED: Thyroid cancer is the most common endocrine cancer today. Differentiated thyroid cancer (DTC) comprises more than 95% of all thyroid cancers. With the increasing incidence of tumors and development of screening, more patients suffer from multiple cancers. The purpose of this study was to explore the prognostic value of a history of prior malignancy for stage I DTC.
UNASSIGNED: Stage I DTC patients were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan-Meier method and Cox proportional hazards regression method were used to determine the risk factors for overall survival (OS) and disease-specific survival (DSS). A competing risk model was also used to determine the risk factors for DTC-related death after considering the competitive risks. In addition, conditional survival analysis in patients with stage I DTC was performed.
UNASSIGNED: A total of 49,723 patients with stage I DTC were enrolled in the study, and 4,982 (10.0%) had prior malignancy history. Prior malignancy history was a factor affecting OS (P<0.001) and DSS (P<0.001) in the Kaplan-Meier analysis and an independent risk factor for OS [hazard ratio (HR) =3.6, 95% confidence interval (CI): 3.17-4.088, P<0.001] and DSS (HR =4.521, 95% CI: 2.224-9.192, P<0.001) in the multivariate Cox proportional hazards regression analysis. In the competing risk model, in the multivariate analysis, prior malignancy history was a risk factor for the DTC-related deaths [subdistribution HR (SHR) =4.32, 95% CI: 2.233-8.3593, P<0.001] after considering the competitive risks. Conditional survival showed that the probability of achieving 5-year DSS was not changed in either the two groups with or without prior malignancy history. For the patients with prior malignancy history, the probability of achieving 5-year OS increased with each additional year survived, but for the patients without prior malignancy history, the improvement of conditional OS only appeared with 2 years already prior survived.
UNASSIGNED: Prior malignancy history has an adverse impact on the survival of patients with stage I DTC. The probability of achieving 5-year OS for stage I DTC patients with prior malignancy history increases with each additional year survived. The inconsistent survival effects of prior malignancy history should be considered in clinical trial design and recruitment.

UNASSIGNED: Differentiated thyroid cancer (DTC) has a high incidence but a generally good prognosis. However, lymph node metastasis is likely to occur. It usually metastasizes from the central group lymph nodes to the deep cervical lymph nodes and less frequently to the sternocleidomastoid-sternohyoid muscle. The lymph nodes between the sternocleidomastoid and sternohyoid muscles (LNSS) is easily overlook. Ignoring the preoperative assessment and dissection of level LNSS, especially in the contralateral neck level LNSS, may lead to incomplete surgery and thus require reoperation. The metastatic relevant factors and pathway for LNSS remains inconclusive require further investigation. There is a lack of reports of contralateral or bilateral cervical level LNSS metastasis in thyroid cancer. We hope to arouse attention to the level LNSS through our two case reports.
UNASSIGNED: We report two cases of non-ipsilateral LNSS metastases. The patients were diagnosed with thyroid cancer by fine-needle aspiration (FNA), and ultrasound examination showed enlarged lymph nodes at the LNSS level. After surgical treatment and postoperative paraffin pathology, both patients were diagnosed with papillary thyroid carcinoma (PTC) and LNSS-level lymph node metastasis. Case 1 was a 63-year-old woman admitted to our hospital with a 15-day history of an untreated thyroid nodule and preoperative euthyroidism. This patient underwent total thyroidectomy, central and left neck LNSS dissection. Her prognosis was good, and there were no signs of recurrence at her 6-month follow-up appointment; Case 2 was a 24-year-old woman admitted to our hospital for a physical examination of an anterior cervical mass that had been present for 1 year and preoperative euthyroidism. This patient underwent total thyroidectomy, central and bilateral neck LNSS dissection. Her prognosis was good, and there were no signs of recurrence at her 12-month follow-up appointment.
UNASSIGNED: The occurrence of contralateral and bilateral simultaneous LNSS metastasis in thyroid cancer is relatively rare. However, in clinical practice, surgeons should focus on the evaluation and clearance of LNSS, especially in patients with cancer foci located in the lower pole, cancer foci invading the anterior cervical band muscle, extensive metastasis in the lateral cervical lymph nodes or stages T3/4 and to reduce postoperative recurrence.

Four anti-thyroglobulin autoantibodies (TgAb) assays were evaluated for their reference interval, method agreement, concordance etc. Prevalence of TgAb and anti-thyroid peroxidase was studied in differentiated thyroid cancer (DTC) and control. Reference intervals for TgAb assays varied from method to method due to varied assay designs. For TgAb correlation coefficients ranged from 0.74 to 0.99 whereas concordance ranged from 81 to 96.1%. Prevalence of thyroid antibodies mainly TgAb was increased in DTC primarily in females. Use of sensitive immunoassays is recommended for thyroid autoantibody measurement. Diagnosis and follow-up are difficult in DTC with coexisting thyroid autoimmunity. Hence, careful monitoring with regular surveillance is suggested.

UNASSIGNED: Distant metastasis (DM) is an important prognostic factor in differentiated thyroid cancer (DTC) and determines the course of treatment. This study aimed to establish a predictive nomogram model that could individually estimate the risk of DM and analyze the prognosis of female DTC patients (FDTCs).
UNASSIGNED: A total of 26,998 FDTCs were retrospectively searched from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2018 and randomly divided into validation and training cohorts. Univariate and multivariate analyses were performed to screen for prognostic factors and construct a prediction nomogram. The performance of the nomogram was assessed by the area under the receiver operating characteristic curve (AUC), concordance index (C-index), and a calibration curve. The overall survival (OS) and cancer-specific survival (CSS) were evaluated by Kaplan-Meier (K-M) analysis.
UNASSIGNED: A total of 263 (0.97%) FDTCs were reported to have DM. K-M analysis showed the association of multiple-organ metastases and brain involvement with lower survival rates (P < 0.001) in patients. Tumor size, age at diagnosis, thyroidectomy, N1 stage, T3-4 stage, and pathological type were independent predictive factors of DM in FDTCs (all P < 0.001). Similarly, age at diagnosis, Black, DM, T3-4 stage, thyroidectomy, and lung metastasis were determined as independent prognostic factors for FDTCs (all P < 0.001). Several predictive nomograms were established based on the above factors. The C-index, AUC, and calibration curves demonstrated a good performance of these nomogram models.
UNASSIGNED: Our study was successful in establishing and validating nomograms that could predict DM, as well as CSS and OS in individual patients with FDTC based on a large study cohort. These nomograms could enable surgeons to perform individualized survival evaluation and risk stratification for FDTCs.

Differentiated thyroid cancer (DTC), arising from thyroid follicular epithelial cells, is the most common type of thyroid cancer. Despite the well-known utilization of radioiodine treatment in DTC, i.e., iodine-131, radioiodine imaging in DTC is typically performed with iodine-123 and iodine-131, with the current hybrid scanner performing single photon emission tomography/computed tomography (SPECT/CT). Positron emission tomography/computed tomography (PET/CT) provides superior visualization and quantification of functions at the molecular level; thus, lesion assessment can be improved compared to that of SPECT/CT. Various types of cancer, including radioiodine-refractory DTC, can be detected by 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), the most well-known and widely used PET radiopharmaceutical. Several other PET radiopharmaceuticals have been developed, although some are limited in availability despite their potential clinical utilizations. This article aims to summarize PET radiopharmaceuticals in DTC, focusing on molecular pathways and applications.

To evaluate the outcomes in differentiated thyroid cancer (DTC) patients who achieved excellent response to initial treatment and developed distant metastasis during follow-up.
Thyroid cancer patients registered in Chang Gung Memorial Hospital thyroid cancer database between January 1979 and December 2019 were assessed.
Among 1053 DTC patients with excellent response to initial therapy, 14 (1.3%) patients developed metastatic disease during follow-up, including 6 males and 8 females with median age of 50.2 years [interquartile range (IQR), 39.9-53.7]. Nine (64.3%) patients had papillary cancer, four (28.6%) had follicular cancer, and one (7.1%) had Hürthle cell cancer. Most patients (92.9%) had stage I disease at diagnosis. The sites of metastasis were lung (71.4%), bone (7.1%), mediastinum (7.1%) and multiple sites (14.3%). With a median follow-up of 18.3 years (IQR, 14.8-23.8), 2 patients had disease-specific mortality. The 5- and 10-year disease-specific survival after the diagnosis of distant metastasis was 92% and 74%, respectively. Multiple sites of metastasis was associated with increased risk of mortality (P = 0.022).
A small proportion of DTC patients with an excellence response to initial therapy developed distant metastasis during follow-up. Multiple organ distant metastases conferred a worse disease-specific survival.