Unfavorable Responses to Radioiodine Therapy in N1b Papillary Thyroid Cancer: A Propensity Score Matching Study

Objective: Regional nodal metastases carry prognostic significance in papillary thyroid cancer (PTC). However, whether different locational nodal metastases correlate with different therapeutic responses remains controversial. We innovatively applied the response to therapy restratification system to evaluate the dynamic disease status after surgery and radioactive iodine (RAI) therapy in PTC patients with different locational nodal metastases.Methods: A total of 585 nondistant-metastatic PTC patients who underwent total thyroidectomy and RAI therapy were retrospectively enrolled. Patients with nodal metastases were categorized into N1a and N1b groups. Propensity score matching was used to balance the bias between the 2 groups. Therapeutic responses were dynamically evaluated, and responses to RAI therapy were classified into excellent (ER), indeterminate (IDR), biochemical incomplete (BIR) and structural incomplete response (SIR).Results: N1b group patients showed a significantly higher pre-ablation stimulated thyroglobulin (Ps-Tg) level than N1a group patients (7.4 ng/mL versus 3.2ng/mL, P<.001). After RAI therapy, N1b group patients took a longer time to achieve ER (9.86 months versus 3.29 months, P<.001) and exhibited a higher proportion of non-ER (IDR, BIR, and SIR) (39.15% versus 17.46%, P<.001) compared to N1a group patients. In logistic regression, N1b and Ps-Tg ≥10 ng/mL were confirmed to be independent factors predicting non-ER (odds ratio: 2.591, and 9.196, respectively). In Cox regression, patients with N1b disease and Ps-Tg ≥10 ng/mL showed significantly lower hazards for achieving ER (hazard ratio: 0.564, and 0.223, respectively).Conclusion: N1b PTC patients showed inferior responses to surgery and RAI therapy compared to N1a patients. N1b was confirmed to be an independent factor predicting unfavorable responses to RAI therapy.Abbreviations: AJCC = American Joint Committee on Cancer; ATA = American Thyroid Association; BIR = biochemical incomplete response; BRAF^V600E = proto-oncogene B-Raf V600E mutation; CI = confidence interval; CT = computed tomography; DNA = deoxyribonucleic acid; DTC = differentiated thyroid cancer; ER = excellent response; ETE = extrathyroidal extension; HR = hazard ratio; IDR = indeterminate response; LNM = lymph node metastasis; N1a = central cervical LNM; N1b = lateral cervical LNM; OR = odds ratio; PSM = propensity score matching; Ps-Tg = pre-ablation stimulated thyroglobulin; PTC = papillary thyroid cancer; RAI = radioactive iodine; SIR = structural incomplete response; Tg = thyroglobulin; TgAb = thyroglobulin antibody; TSH = thyroid-stimulating hormone     

Serial Neck Ultrasound is More Likely to Identify False-Positive Abnormalities than Clinically Significant Disease in Low-Risk Papillary Thyroid Cancer Patients

Objective: American Thyroid Association (ATA) low-risk papillary thyroid cancer (PTC) patients without structural evidence of disease on initial posttreatment evaluation have a low risk of recurrence. Despite this, most patients undergo frequent surveillance neck ultrasound (US). The objective of the study was to evaluate the clinical utility of routine neck US in ATA low-risk PTC patients with no structural evidence of disease after their initial thyroid surgery.Methods: We performed a retrospective review of 171 ATA low-risk PTC patients after total thyroidectomy, with or without radioactive iodine (RAI) ablation, who had a neck US without suspicious findings after therapy. The main outcome measure was a comparison of the frequency of finding false-positive US abnormalities and the frequency of identifying structural disease recurrence.Results: Over a median follow-up of 8 years, 171 patients underwent a median of 5 neck US (range 2–17). Structural recurrence with low-volume disease (≤1 cm) was identified in 1.2% (2/171) of patients at a median of 2.8 years (range 1.6–4.1 years) after their initial diagnosis. Recurrence was associated with rising serum thyroglobulin (Tg) level in 1 of the 2 patients and was detected without signs of biochemical recurrence in the other patient. Conversely, false-positive US abnormalities were identified in 67% (114/171) of patients after therapy, leading to additional testing without identifying clinically significant disease.Conclusion: In ATA low-risk patients without structural evidence of disease on initial surveillance evaluation, routine screening US is substantially more likely to identify false-positive results than clinically significant structural disease recurrence.Abbreviations:18FDG-PET = 18-fluorodeoxyglucose-positron emission testingAJCC = American Joint Committee on CancerATA = American Thyroid AssociationCT = computed tomographyETA = European Thyroid AssociationMRI = magnetic resonance imagingPTC = papillary thyroid cancerRAI = radioactive iodineTg = thyroglobulinTgAb = antithyroglobulin antibodiesTSH = thyroid-stimulating hormoneUS = ultrasound     

Prognosis of High-Risk Papillary Thyroid Cancer Patients with Pre-Ablation Stimulated TG <1 NG/ML

Objective: The prevalence of undetectable pre-ablation stimulated thyroglobulin (s-Tg) and its clinical implications in high-risk papillary thyroid cancer (PTC) patients remain poorly described. We investigated the rate of tumor recurrence in PTC patients initially classified as high risk but with pre-ablation s-Tg <1 ng/mL and negative anti-Tg antibody (TgAb).Methods: In order to have a follow-up period of at least 5 years for each patient, PTC patients consecutively seen at our department from May 2008 to June 2013 with the following characteristics were selected: (i) classified as American Thyroid Association high risk on the basis of tumor histopathologic features; (ii) submitted to adjuvant ¹³¹I therapy after total thyroidectomy; (iii) a postoperative pre-ablation s-Tg <1 ng/mL and negative TgAb.Results: Among 767 high-risk PTC patients submitted to adjuvant ¹³¹I therapy, 69 patients met the inclusion criteria. Sixty-seven patients (97.1%) were diagnosed as classical PTC, and the remaining 2 patients (2.9%) were diagnosed as follicular variant PTC. When evaluated 9 to 12 months after ¹³¹I therapy, 67 patients (97.1%) were classified as excellent response. Two (2.9%) patients had an s-Tg >1 ng/mL (<3 ng/mL) in the absence of apparent disease, as detected by imaging methods (indeterminate response). During a median follow-up duration of 5.6 years, recurrence was observed in only 2 (2.9%) patients. The 67 (97.1%) patients without tumor recurrence were not submitted to any additional therapy, and all had a suppressed Tg <1 ng/mL in the last assessment.Conclusion: High-risk PTC patients with pre-ablation s-Tg <1 ng/mL and negative TgAb had a favorable prognosis.Abbreviations: CT = computed tomography; L-T4 = levothyroxine; PTC = papillary thyroid cancer; SPECT/CT = single photon emission computed tomography/computed tomography; s-Tg = stimulated thyroglobulin; T4 = thyroxine; TgAb = anti-thyroglobulin antibody; US = ultrasound     

Autonomously Functioning Thyroid Nodules In Patients &#x003c;21 Years Of Age: The Rhode Island Hospital Experience From 2003&#x00C2;&#x20AC;&#x201C;2013

Objective: This study evaluates the clinical characteristics, workup, treatment, and outcomes of pediatric patients diagnosed with an autonomously functioning thyroid nodule (AFTN) in a large cohort of patients presenting for evaluation of a thyroid nodule. There are few prior studies on AFTN in pediatrics, with limited data on treatment and outcomes. Rates of malignancy in AFTN are perceived as low, but prior studies have varying reports.Methods: This is a retrospective chart review of patients less than 21 years of age at Rhode Island Hospital over an 11-year period (2003&#x00E2;&#x20AC;&#x201C;2013). We reviewed 354 charts, which yielded 242 patients with a diagnosis of thyroid nodule and 17 patients with AFTN.Results: The prevalence of AFTN in patients presenting with thyroid nodules was 7%. Mean age of patients was 15.8 years at diagnosis, and mean nodule size was 3.3 cm. There was female predominance. Thyroid-stimulating hormone levels were suppressed at diagnosis in 87% of patients. Six patients were treated with surgery, 5 patients with radioactive iodine therapy (RAI), 2 patients with medication, and 1 patient was observed without treatment. Three patients treated with RAI required subsequent treatment for hypothyroidism or continued hyperthyroidism. One patient had papillary thyroid carcinoma based on final surgical pathology.Conclusion: Our study found a higher prevalence of AFTN compared to the reported prevalence in adults. We concur with the new guidelines on management of thyroid nodules in recommending surgery for treatment of AFTN, based on the variability of outcomes after treatment with RAI.Abbreviations:AFTN = autonomously functioning thyroid noduleanti-TG = thyroglobulin antibodiesanti-TPO = thyroid peroxidase antibodiesFNA = fine-needle aspirationICD-9 = International Classification of Diseases, Ninth RevisionPTC = papillary thyroid carcinomaRAI = radioactive iodineT₃ = triiodothyronineT₄ = thyroxineTSH = thyroid-stimulating hormoneTSI = thyroid-stimulating immunoglobulin     

Prognostic Value of Lymph Node Uptake on Pretreatment F-18 FDG PET/CT in Patients with N1B Papillary Thyroid Carcinoma

Objective: The aim of this study was to investigate the prognostic value of metabolic characteristics of metastatic lymph node (LN) using pretreatment F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for patients with papillary thyroid carcinoma (PTC) and metastatic lateral LN (N1b).Methods: Ninety-six PTC patients (female:male = 72:24; median age, 44.5 years) with pathologic N1b who underwent pretreatment FDG PET/CT, total thyroidectomy, and radioactive iodine ablation were retrospectively reviewed. To predict responses to initial therapy and recurrence, clinicopathologic factors and metabolic parameters were reviewed, such as sex, age, tumor size, extranodal extension, number and ratio of metastatic LNs, serum thyroglobulin, and maximum standardized uptake value (SUVmax).Results: Among the 96 PTC patients, 81 (84.4%) were classified into the acceptable response (58 excellent; 23 indeterminate) and 15 (15.6%) into the incomplete response (8 biochemical incomplete; 7 structural incomplete) by the 2015 American Thyroid Association management guideline for differentiated thyroid carcinoma. The multivariate analysis showed that SUVmax of N1b (P = .018), pre-ablation stimulated thyroglobulin level (P = .006), and the ratio of metastatic LNs (P = .018) were related to incomplete response. The cutoff value of each variable was determined by receiver operating characteristic analysis. Nine (9.4%) patients experienced recurrences (median follow-up: 50 months). The Kaplan-Meier analysis revealed that SUVmax of N1b (cutoff value: 2.3; P = .025) and ratio of metastatic LNs (cutoff value: 0.218; P = .037) were significant prognostic factors for recurrence.Conclusion: High SUVmax of N1b cervical LN on pretreatment FDG PET/CT could predict incomplete responses to initial therapy and recurrence in patients with N1b PTC.Abbreviations: ATA = American Thyroid Association; DTC = well-differentiated thyroid carcinoma; FDG = F-18 fluorodeoxyglucose; IQR = interquartile range; LN = lymph node; N1b = metastatic lateral cervical lymph node; PET/CT = positron emission tomography/computed tomography; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; ROC = receiver operating characteristic; SUVmax = maximum standardized uptake value; Tg = thyroglobulin; USG = ultrasonography     

Unilateral Tnm T1 And T2 Papillary Thyroid Carcinoma With Lateral Cervical Lymph Node Metastasis: Total Thyroidectomy or Lobectomy?

Objective: The aim of this study was to explore the effect of total thyroidectomy (TT) and lobectomy (LT) on the prognosis of unilateral papillary thyroid carcinoma (PTC) with lateral cervical lymph node metastasis.Methods: Patients with PTC and lateral cervical lymph node metastasis who underwent lateral cervical lymph node dissection between January 2007 and December 2016 were retrospectively reviewed. To investigate the effect of surgical procedure on the prognosis of lymph node metastasis patients, other high-risk factors such as extrathyroidal invasion and large tumor size were excluded. All patients were in Tumor-Node-Metastasis (TNM) stage T1 and T2. Primary end point was recurrence-free survival (RFS).Results: Among 264 PTC patients, 104 (39.4%) patients received TT and 160 (60.6%) patients received LT. With a median follow-up of 50 months (interquartile range, 34 to 74 months), 7 patients (2.65%) experienced recurrence. The 5-year RFS in the TT and LT groups was 96.1% and 97.7%, respectively, and was not significantly different (P = .765). Similar results were found when excluding patients who received radioiodine ablation, which were 97.7% and 97.4%, respectively (P = .752). Age ≥55 years (hazard ratio, 7.368; P = .018) and multifocality in the ispi-lateral lobe (hazard ratio, 10.059; P =.006) were identified as independent risk factors of recurrence.Conclusion: For unilateral TNM T1 and T2 PTC patients with lateral lymph node metastasis, there was no significant difference in the effect of TT and LT for RFS in the absence of other risk factors during the follow-up period. Patient age ≥55 years with multifocality in the unilateral lobe might be independent risk factors for prognosis.     

Lateral Neck Dissection for Aggressive Variants of Well-Differentiated Thyroid Cancer

Objective: Well-differentiated thyroid cancer (WDTC) is characterized by favorable disease course and excellent survival. However, some histologic subtypes, known as aggressive histologic variants (AHVs), present a more aggressive behavior than conventional WDTC. The aim of this study was to evaluate the pattern of nodal involvement and factors influencing prognosis in N1b patients with AHVs.Methods: A multicentric retrospective analysis of patients who underwent therapeutic lateral neck dissection (ND) for WDTC between 1994 and 2015 was accomplished. AHVs included the following subtypes: tall cell, Hürtle cell, diffuse sclerosing, and poorly differentiated papillary thyroid cancer.Results: The study included a total of 352 N1b patients, 40 (11.4%) of whom had AHVs. AHVs present a similar distribution of positive nodes if compared with conventional WDTC. In AHV patients, 5-year overall survival (OS), disease-specific survival (DSS), locoregional control, and metastasis-free survival were 82.2%, 93.6%, 80.3%, and 87.3%, respectively. Advanced age (>55 years) was the only significant factor affecting survival (OS, P<.001; DSS, P = .011) in this group. In the AHV group, there were 9 (22.5%) recurrences; patients with regional recurrence and without distant metastases were effectively treated by surgery.Conclusion: The distribution of positive lymph nodes in case of AHVs is similar to that of conventional WDTC, with only level V at a relatively greater risk of harboring metastases in the former group. Survival outcomes in N1b patients with AHVs remain optimal. Total thyroidectomy, ND, and adjuvant radioiodine administration have been demonstrated to be effective treatments in the setting of AHVs.Abbreviations: AHV = aggressive histologic variant; DOD = died of disease; DSS = disease-specific survival; DSV = diffuse sclerosing variant; ETE = extrathyroidal extension; HCC = Hürthle cell carcinoma; LRC = locoregional control; LVI = lymphovascular invasion; MFS = metastasis-free survival; ND = neck dissection; NED = no evidence of disease; OS = overall survival; PDA = poorly differentiated areas; PTC = papillary thyroid carcinoma; RAI = radioiodine therapy; TCV = tall cell variant; WDTC = well-differentiated thyroid cancer     

Tumor Size is an Independent Predictor of Mortality Risk in Differentiated Thyroid Cancer Patients with T4 Disease

Objective: The eighth edition of the American Joint Committee on Cancer (AJCC) guideline on the tumor-node-metastasis staging system has been applied in clinical practice for thyroid cancer since 2018. However, using these criteria, a few studies have shown no significant difference between stage III and IV diseases amongst the differentiated thyroid cancer (DTC) patients. Thus, we aimed to study the underlying reason behind this observation.Methods: Patients were selected from the Surveillance, Epidemiology, and End Results database between 2004 and 2015. The Cox proportional hazards regression model was used for the univariate and multivariate analyses to plot the Kaplan-Meier survival curves for overall survival (OS) and disease-specific survival (DSS).Results: A total of 1,431 patients had a median tumor size of 3.0 cm (range: 0.1 to 50 cm). When stratified by tumor size (≤2 cm, 2 to 4 cm, and >4 cm), lower survival rates were observed in patients with stage III (T4a) cancer and large tumor size than in those with stage IVA (T4b) cancer and small tumor size. Univariate and multivariate analyses showed that tumor size (≤4 cm versus >4 cm) is an independent prognostic factor for OS (P<.001) and DSS (P<.001) in DTC patients with T4a and T4b diseases.Conclusion: Tumor size is an independent prognostic factor for OS and DSS in DTC patients with T4 disease; tumor size-related modification of the T4 category can improve the AJCC staging system for DTC patient with stage III–IV diseases.Abbreviations: AJCC = American Joint Committee on Cancer; CI = confidence interval; DSS = disease-specific survival; DTC = differentiated thyroid cancer; FTC = follicular thyroid cancer; HR = hazard ratio; OS = overall survival; PTC = papillary thyroid cancer; SEER = Surveillance, Epidemiology, and End Results; TNM = tumor-node-metastasis     

Increased Risk of Radioiodine Treatment Failure Associated with Graves Disease Refractory to Methimazole

Objective: Iodine 131 (I-131) radioactive iodine (RAI) therapy has been the preferred treatment for Graves disease in the United States; however, trends show a shift toward antithyroid drug (ATD) therapy as first-line therapy. Consequently, this would favor RAI as second-line therapy, presumably for ATD refractory disease. Outcomes of RAI treatment after first-line ATD therapy are unclear. The purpose of this study was to investigate treatment failure rates and potential risk factors for treatment failure, including ATD use prior to RAI treatment.Methods: A retrospective case control study of Graves disease patients (n = 200) after I-131 RAI therapy was conducted. Treatment failure was defined as recurrence or persistence of hyperthyroidism in the follow-up time after therapy (mean 2.3 years). Multivariable regression models were used to evaluate potential risk factors associated with treatment failure.Results: RAI treatment failure rate was 16.5%. A majority of patients (70.5%) used ATD prior to RAI therapy, predominantly methimazole (MMI) (91.9%), and approximately two-thirds of patients used MMI for >3 months prior to RAI therapy. Use of ATD prior to RAI therapy (P = .003) and higher 6-hour I-123 thyroid uptake prior to I-131 RAI therapy (P<.001) were associated with treatment failure. MMI use >3 months was also associated with treatment failure (P = .002).Conclusion: More patients may be presenting for RAI therapy after failing first-line ATD therapy. MMI use >3 months was associated with RAI treatment failure. Further studies are needed to investigate the association between long-term first-line ATD use and RAI treatment failure.     

Effect of Post-Surgical Rai Therapy on Parathyroid Function in Patients with Differentiated Thyroid Cancer

Objective: Radiotherapy with radioactive iodine (RAI) has become a common treatment for postsurgical differentiated thyroid carcinoma (DTC). The objective of this study was to determine the effect of RAI therapy following surgery on the function of the parathyroid glands in DTC patients.Methods: A total of 81 DTC patients who received RAI therapy after surgery were enrolled in the study. The size of the residual thyroid was detected by technetium-99m (^99mTc)-pertechnetate thyroid scan (^99mTc thyroid scan) before RAI therapy. The iodine uptake ability of residual thyroid was evaluated by iodine-131 (¹³¹I) whole-body scan (WBS). All patients were treated with an activity of 3.7 GBq (100 mCi) ¹³¹I. Parathyroid hormone (PTH), serum calcium, phosphorus, and magnesium were evaluated at 1 day before treatment, and at 1 month and 3 months after treatment.Results: The results show that there was no statistically significant difference in blood PTH level observed (P>.05) between 3 time points (pre-treatment, 1 month post-treatment and 3 months post-treatment). The serum calcium and phosphorus did not change significantly (P>.05), but serum magnesium level was elevated after treatment (P<.05). There were no significant differences between PTH changes and sex, age, scores of ^99mTc thyroid scan, scores of ¹³¹I WBS, Tumor (T) stage, and Node (N) stage.Conclusion: RAI therapy following surgery did not significantly affect parathyroid function in DTC patients.Abbreviations: ATA = American Thyroid Association; DTC = differentiated thyroid carcinoma; FT3 = free triiodothyronine; FT4 = free thyroxine; 131I = iodine-131; PTH = parathyroid hormone; RAI = radioiodine; 99mTc = Technetium-99m; TG = thyroglobulin; TNM = Tumor Node Metastasis; TSH = thyroid-stimulating hormone; WBS = whole-body scan     

Serum Adiponectin And Insulin-Like Growth Factor 1 In Predominantly Female Patients With Thyroid Cancer: Association With The Histologic Characteristics Of The Tumor

Objective: Insulin-like growth factor (IGF)-1 and adiponectin have been proposed to contribute to the pathogenesis of different malignancies. However, data regarding their association with histologic characteristics of thyroid cancer are scarce. The main aims of the present study were the comparative evaluation of IGF-1, IGF-binding protein 3 (BP3), and adiponectin serum levels between different histologic types of thyroid cancer, as well as within specific histologic characteristics of the tumors.Methods: A total of 179 thyroid cancer patients (126 [70.4%] women) were recruited. A total of 129 (72.1%) had papillary thyroid carcinoma (including variants), 26 had follicular thyroid carcinoma (14.5%), and 24 had medullary thyroid carcinoma (13.4%). Parameters from history, physical examination, and thyroid histology were selected. Serum adiponectin, IGF-1, and IGF-BP3 were measured in fasting morning samples.Results: IGF-1, IGF-BP3, and adiponectin levels were similar among different histologic types of thyroid carcinoma, with a trend towards higher IGF-1 and IGF-BP3 levels in patients with intrathyroid invasion, compared to those without. In addition, ratios of IGF-1 to adiponectin (P = .012) and IGF-1 to (adiponectin × IGF-BP3) (P = .003), as well as type 2 diabetes (P = .001), were positively associated with tumor size.Conclusion: Although IGF-1, IGF-BP3, and adiponectin were not separately different between groups or within specific histologic lesions, when they were combined to produce IGF-1 to adiponectin and IGF-1 to (adiponectin × IGF-BP3) ratios, they were independently associated with tumor size. Future prospective studies are needed to evaluate whether these ratios could serve as prognostic markers of thyroid tumor aggressiveness.Abbreviations:CI = confidence intervalIGF-1 = insulin-like growth factor-1IGF-1R = insulin-like growth factor 1 receptorIGF-BP3 = insulin-like growth factor binding protein 3MTC = medullary thyroid carcinomaOR = odds ratioPTC = papillary thyroid carcinomaPTC-fv = papillary thyroid carcinoma-follicular variantT2DM = type 2 diabetes mellitus     

Active Surveillance for Papillary Thyroid Microcarcinoma: New Challenges and Opportunities for The Health Care System

Objective: The dramatic increase in papillary thyroid carcinoma (PTC) is primarily a result of early diagnosis of small cancers. Active surveillance is a promising management strategy for papillary thyroid microcarcinomas (PTMCs). However, as this management strategy gains traction in the U.S., it is imperative that patients and clinicians be properly educated, patients be followed for life, and appropriate tools be identified to implement the strategy.Methods: We review previous active surveillance studies and the parameters used to identify patients who are good candidates for active surveillance. We also review some of the challenges to implementing active surveillance protocols in the U.S. and discuss how these might be addressed.Results: Trials of active surveillance support nonsurgical management as a viable and safe management strategy. However, numerous challenges exist, including the need for adherence to protocols, education of patients and physicians, and awareness of the impact of this strategy on patient psychology and quality of life. The Thyroid Cancer Care Collaborative (TCCC) is a portable record keeping system that can manage a mobile patient population undergoing active surveillance.Conclusion: With proper patient selection, organization, and patient support, active surveillance has the potential to be a long-term management strategy for select patients with PTMC. In order to address the challenges and opportunities for this approach to be successfully implemented in the U.S., it will be necessary to consider psychological and quality of life, cultural differences, and the patient's clinical status.Abbreviations:CT = computed tomographyPTC = papillary thyroid carcinomaPTMC = papillary thyroid microcarcinomaTCCC = Thyroid Cancer Care Collaborative     

Size of the Largest Metastatic Focus to the Lymph Node is Associated with Incomplete Response of Pn1 Papillary Thyroid Carcinoma

Objective: To evaluate the influence of the size of the metastatic focus in lymph nodes (LNs) on therapeutic response among papillary thyroid cancer (PTC) and cervical pathologically proven LN metastases (pN1).Methods: Patients with pN1 PTC who underwent total or near-total thyroidectomy, LN dissection, and postoperative radioactive iodine therapy in a university hospital between 2014 and 2016 were retrospectively reviewed. Furthermore, 554 patients were assigned to three groups according to the size of the metastatic focus in the LNs (≤0.2 cm, 0.2 to 1.0 cm, ≥1.0 cm). Structural incomplete response (SIR) was defined as structural or functional evidence of disease with any thyroglobulin level and/or anti-thyroglobulin antibodies.Results: Among the 554 patients, the proportion of patients with SIR was 2.5% (4/161) in group 1, 13.9% (37/267) in group 2, and 46.8% (59/126) in group 3 (χ² = 100.073; P<.001). The optimal cutoff value of the size of the largest metastatic focus to the LNs was 0.536 cm to predict SIR with a corresponding sensitivity of 0.82, a specificity of 0.716, and an area under the curve of 0.821 (95% confidence interval &lsqb;CI], 0.777 to 0.864; P<.001). Size of the largest metastatic focus to the LNs was confirmed to be an independent predictive factor for SIR (odds ratio, 9.650; 95% CI, 4.925 to 18.909; P<.001).Conclusion: In patients with pN1 PTC, there is an association between the size of the largest metastatic focus to the LNs and incomplete response.Abbreviations: AJCC = American Joint Committee on Cancer; ATA = American Thyroid Association; BIR = biochemical incomplete response; CI = confidence interval; ER = excellent response; ETE = extranodal extension; 18F-FDG = 18F-fluorodeoxyglucose; IDR = indeterminate response; LN = lymph node; OR = odds ratio; PET/CT = positron emission tomography/computed tomography; pN1 = pathologically proven LN metastases; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; ROC = receiver operating characteristic; SIR = structural incomplete response; sTg = stimulated thyroglobulin; TgAb = anti-thyroglobulin antibody; TSH = thyroid-stimulating hormone     

Long-Term Outcomes and Prognostic Factors in Patients With Differentiated Thyroid Carcinoma and Bone Metastases

Objective: This institutional study sought to retrospectively evaluate disease progression and survival of patients with differentiated thyroid cancer (DTC) and bone metastases (BM) and to investigate variables predictive of better long-term outcomes.Methods: The Rabin Medical Center Thyroid Cancer Registry was searched for patients with bone-metastatic DTC. Variables including a patient's gender and age, pathology of the thyroid tumor, and characteristics of BM were retrieved and analyzed in association with disease progression and mortality.Results: The cohort included 64 patients (48.4% female). Mean age at diagnosis was 62.1 ± 14.3 years; mean primary tumor size was 41 ± 30 mm. Overall, 60.4% had stage T3/T4 disease; 46.3% had extrathyroidal extension; 40% had lymph-node metastases. Histopathology yielded papillary and follicular DTC in 40.6% and 32.8% of patients, respectively, and poorly/intermediately differentiated carcinoma in 26.6%. BM were synchronous in 50%. Mean follow-up was 11 ± 9.6 years from DTC detection. The common first sites of BM detection were spine (46.9% of patients), pelvis (37.5%) and ribs (21.9%). Nineteen patients (29.7%) presented with multiple-site BM, of whom 15 (78.9%) had spinal metastases. After initial treatment, 62/64 patients had structural persistence, and at last follow-up, 57.8% had progressive disease. Overall, 54.7% of patients died, 71.4% of DTC. Improved long-term outcomes were associated with younger age, lower tumor stage, no extrathyroidal extension, bone-only metastases, and non-spinal BM. Younger age and non-spinal BM were the only independent predictors for improved survival.Conclusions: Selected patients with bone-metastatic DTC may achieve fair long-term outcomes. Spinal metastases are associated with disseminated skeletal spread and increased mortality.Abbreviations: BM = bone metastases; COX = multivariate analyses; DM = distant metastases; DSM = disease-specific mortality; DSS = disease-specific survival; DTC = differentiated thyroid carcinoma; ETE = extrathyroidal extension; LNM = lymph node metastases; OM = overall mortality; OS = overall survival; PTCFV = papillary thyroid carcinoma; RAI = radioactive iodine; SM = spinal metastases; SRE = skeletal-related event; txWBS = whole-body scan after RAI therapy     

Does T Stage Affect Prognosis in Patients With Stage Iv B Differentiated Thyroid Cancer

Objective: Differentiated thyroid cancer (DTC), the most common subtype of thyroid cancer, has a relatively good prognosis. The 8^th edition of the American Joint Committee on Cancer (AJCC) pathologic tumor-node-metastasis (T &lsqb;primary tumor size], N &lsqb;regional lymph nodes], M &lsqb;distant metastasis]) staging system did not take the T stage into consideration in stage IV B DTC patients. We evaluated the prognostic value of the T stage for advanced DTC survival.Methods: DTC cases that were considered stage IV B in the AJCC 8^th edition were extracted from the Surveillance, Epidemiology, and End Results database. T stage (AJCC 6^th standard) was categorized into T0–2, T3 and T4. We analyzed overall survival (OS) and cancer specific survival (CSS) in the overall group as well as in pathologic subgroups. We used the Kaplan-Meier method and log-rank test for univariate analysis and the Cox regression model for multivariate analysis.Results: A total of 519 cases were extracted. Patients with earlier T stages showed significantly better OS and CSS in univariate analysis. T stage was an independent prognostic factor for both OS and CSS in multivariate analysis. Subgroup analysis in papillary and follicular thyroid cancer showed that T4 was an independent prognostic factor for both OS and CSS.Conclusion: AJCC 8 stage IV B DTC patients could be further stratified by T stage. Further studies with larger samples and AJCC 8 T stage information are necessary.Abbreviations: AJCC = American Joint Committee on Cancer; CI = confidence interval; CSS = cancer specific survival; DTC = differentiated thyroid cancer; FTC = follicular thyroid cancer; FVPTC = follicular variant of papillary thyroid carcinoma; HR = hazard ratio; OS = overall survival; PTC = papillary thyroid cancer; SEER = surveillance, epidemiology, and end results database     

Programmed Cell Death–Ligand 1 Overexpression in Thyroid Cancer

Objective: Programmed cell death–ligand 1 (PD-L1) expression on tumor tissue has been associated with favorable response to anti–programmed cell death–receptor 1/PD-L1 therapy in many human cancers. Studies have reported that PD-L1 is also expressed in thyroid cancer. The objective of this paper is to introduce the potential predictive and therapeutic values of PD-L1 in thyroid cancer.Methods: A literature search was conducted in the PubMed database using the terms “PD-L1,” “B7-H1,” and “thyroid cancer.” PD-L1 positivity was determined by immunohistochemical assay.Results: The frequency of PD-L1 positivity in different studies ranged from 6.1 to 82.5% in papillary thyroid cancer (PTC) patients and 22.2 to 81.2% in anaplastic thyroid cancer (ATC) patients. PD-L1 positivity rate was higher in ATC than in PTC within the same studies, and its expression intensity was significantly higher in tumor tissue than in the corresponding nontumor thyroid tissues. Moreover, PD-L1 expression was positively associated with the aggressiveness and recurrence of thyroid cancers and negatively associated with the differentiation status and outcomes. PD-L1 checkpoint pathway blockade may emerge as a promising therapeutic target in the treatment of thyroid cancers.Conclusion: PD-L1 is a potential biomarker to predict the recurrence and prognosis of thyroid cancers. It is also a novel immunotherapy target for optimizing the management landscape of radioiodine-refractory and ATCs.Abbreviations: ATC = anaplastic thyroid cancer; DTC = differentiated thyroid cancer; IHC = immunohistochemical; OS = overall survival; PD-1 = programmed cell death–receptor 1; PD-L1 = programmed cell death–ligand 1; PD-L2 = programmed cell death–ligand 2; PTC = papillary thyroid cancer; TNM = tumor-node-metastasis; Treg = regulatory T cell     

The Association Between Tumor Tissue Calcification,Obesity, and Thyroid Cancer Invasiveness In A Cohort Study

Objective: We examined the relationships between tumor tissue calcifications of papillary thyroid cancer (PTC), body mass index (BMI), and tumor invasiveness.Methods: This was a retrospective analysis of 13,995 patients with PTC. Comparisons were made between the clinical and pathologic features of the tumor tissue calcifications group and non–tumor tissue calcifications group. Odds ratios (ORs) of tumor tissue calcifications, BMI, and tumor invasiveness features were calculated using a binary logistic regression model. We analyzed the relationship between tumor tissue calcifications and certain characteristics of thyroid cancer based on the pathologic findings.Results: BMI was positively correlated with tumor tissue calcifications in patients with PTC (OR, 1.015; P = .011), and obesity increased the risk of tumor tissue calcifications (OR, 1.374; P = .038). Calcifications were positively correlated with T-size (OR, 1.899; P<.001), multifocality (OR, 1.217; P<.001), extrathyroidal extension (ETE) (OR, 1.287; P<.001), high T-stage (OR, 1.765; P<.001), N+ (OR, 1.763; P<.001), and a higher number of lymph node metastases (OR, 1.985; P<.001). Compared with normal-weight patients with tumor tissue calcifications, obese patients with tumor tissue calcifications had an increased risk of ETE (OR_obesity, 1.765 vs. OR_normal, 1.300) and N+ (OR_obesity, 1.992 vs. OR_normal, 1.784).Conclusion: Tumor tissue calcifications are positively correlated with the invasiveness of PTC. Obesity further promotes the risk of tumor invasiveness in PTC combined with tumor tissue calcifications. These findings suggest that more comprehensive evaluations by trained pathologists may help physicians identify the optimal therapeutic regimens in the postoperative period.Abbreviations: BMI = body mass index; CI = confidence interval; ETE = extrathyroidal extension; FT3 = free triiodothyronine; OR = odds ratio; PTC = papillary thyroid carcinoma; RET = rearranged during transfection; TTC = tumor tissue calcification; US = ultrasonography; USC = ultrasonography calcification; WHO = World Health Organization     

Sonographic Features Of Multifocal Papillary Thyroid Carcinomas

Objective: It is uncertain whether papillary thyroid carcinomas (PTCs) of the same subtype display similar sonographic features. This retrospective analysis of pre-operative sonographic and pathologic findings aimed to assess whether PTCs of the same subtype share sonographic features.Methods: Before undergoing thyroid surgery, 137 patients underwent ultrasound (US) examination. A single radiologist used a picture archiving and communication system and pathologic reports to investigate all sonographic features of the largest and second largest PTCs. Additionally, the radiologist evaluated the similarity of sonographic features between primary (largest), secondary (second largest), and daughter (secondary with same subtype as the primary) PTCs.Results: Of the 137 PTC patients, 48 (35.0%) had multiple PTCs; however, 5 had no US images of the secondary PTC. Of the 43 secondary PTCs with US images, 9 (20.9%) secondary PTCs were of a different subtype than the primary PTC and revealed sonographic features that differed from those of the primary PTC. Of the 48 patients with multiple PTCs, the subtype was the same in the primary and secondary PTCs in 34 (70.8%) patients. Of the 34 daughter PTCs, 32 (94.1%) had sonographic features similar to those of the primary PTC, whereas 2 (5.9%) showed different sonographic features than the primary PTC. There was no significant difference between primary and daughter PTCs in the size, location, sonographic features, or Korean Thyroid Imaging Reporting and Data System category (P>.05).Conclusion: Daughter PTCs show similar sonographic features as the primary PTC.Abbreviations: K-TIRADS = Korean Thyroid Imaging Reporting and Data System; PTC = papillary thyroid carcinoma; US = ultrasound