Effect of Radioactive Iodine Therapy on Cancer-Specific Survival of Papillary Thyroid Cancer Tall Cell Variant.

CONTEXT: Radioactive iodine (RAI) therapy is often used as an adjuvant treatment to reduce the risk of recurrence in patients with papillary thyroid cancer (PTC). However, the effect of RAI therapy on cancer-specific survival (CSS) in patients with tall cell variant (TCV) remains controversial. OBJECTIVE: This study aimed to investigate the impact of RAI therapy on CSS in patients with TCV-PTC by analyzing data from the Surveillance, Epidemiology, and End Results database. METHODS: We identified 1281 patients with TCV-PTC in the SEER database who underwent total thyroidectomy between 2004 and 2019. Of these, 866 (67.6%) patients received RAI therapy and 415 (32.4%) did not. Propensity score matching was conducted to balance the baseline characteristics between the 2 groups. Cox proportional hazards regression models were used to estimate the hazard ratio (HR) and 95% CI for the effect of RAI therapy on CSS. RESULTS: After propensity score matching, 373 pairs of patients were included in the analysis. The results showed no significant difference in CSS between the RAI therapy group and the non-RAI therapy group (HR 0.54, 95% CI 0.25-1.17, P = .120). Subgroup analyses indicated similar results. CONCLUSION: RAI therapy may not improve CSS in patients with TCV-PTC after total thyroidectomy. Future studies with larger sample sizes, longer follow-up periods, and better study designs are needed to confirm or refine our research findings.

Long-term clinical outcomes and prognostic factors for patients with papillary thyroid carcinoma with other organ invasions after adjuvant radioactive iodine.

PURPOSE: Papillary thyroid carcinoma (PTC) with other organ invasions is directly related to patient prognosis and quality of life; however, studies on the clinical outcomes of adjuvant radioactive iodine (RAI) for PTC with other organ invasions are limited. This study aimed to clarify the clinical outcomes and prognostic factors for patients with PTC with other organ invasions after adjuvant RAI. METHODS: Patients with PTC with other organ invasions without distant metastases who underwent surgery and adjuvant RAI were retrospectively reviewed. We evaluated the initial responses based on the American Thyroid Association guidelines and survival rates. Prognostic factors for locoregional recurrence-free survival (LRRFS) were analyzed. RESULTS: Between January 2005 and December 2019, 102 patients were included in the study. Their median age was 55 years. The median follow-up duration was 92 months (range; 30-231 months). The excellent response rate after RAI was 42%. The 7-year overall survival, LRRFS, and recurrence-free survival rates were 100%, 75%, and 75%, respectively. Metastatic lymph node size, resection margin status, and post-RAI suppressed thyroglobulin level were the independent prognostic factors for LRRFS. CONCLUSION: We demonstrated that 75% of patients with PTC with other organ invasions could achieve long-term survival without recurrence after adjuvant RAI. Future development of effective treatment strategies for large metastatic lymph nodes, gross residual tumors, and high serum thyroglobulin levels is warranted.

Potential Impact of Body Mass Index on the Clinical Outcome of Papillary Thyroid Cancer After High-Dose Radioactive Iodine Therapy.

Context: Obesity has been reported as a potential risk factor for the aggressiveness of papillary thyroid cancer (PTC), but the data gathered so far are conflicting. Objective: The aim of our study was to evaluate the relationship between body mass index (BMI) and aggressiveness of PTC at the diagnosis and clinical outcome. Methods: A total of 337 patients who underwent radioactive iodine (RAI) therapy between March 2017 and May 2020 were recruited. Patients were divided into four groups: underweight (BMI<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (BMI≥ 30 kg/m2). Treatment and follow-up were defined according to criteria used in the 2015 ATA guidelines. Results: This study included 337 patients with PTC (71.5% women, median age 45.21 ± 13.04 years). The mean BMI was 24.2 ± 3.1 kg/m2. Obese groups had a higher age than the other groups (P = 0.001). Moreover, obese patients had larger tumor sizes and higher T stage, compared to overweight, normal weight, and underweight patients (P = 0.007). After a median follow-up of 32 months, 279 patients (82.7%) had achieved an excellent response (ER) to therapy. The overall ER rates were compared between groups, and they did not differ significantly. Conclusions: We demonstrated that BMI may have an additive effect on the aggressiveness of PTC, but did not have an effect on the response to therapy after high-dose RAI therapy.

The role of adjuvant radiation therapy for locoregionally recurrent papillary thyroid carcinoma.

OBJECTIVES: To evaluate the role of adjuvant radiation therapy in patients with locoregionally recurrent (rpT4/N1b) papillary thyroid carcinoma (PTC). METHODS: The medical records of patients with rpT4/N1b PTC who were treated between January 2001 and December 2016 were reviewed. A total of 57 patients were analyzed, of which 24 patients were treated with adjuvant radiation therapy, and 33 patients did not receive adjuvant radiation therapy. Survival outcomes were compared between the 2 treatment groups. The primary endpoint was locoregional recurrence-free survival rate. RESULTS: The median follow-up period for all patients was 10.3 years (range, 2.8-19.2 years). The 15-year locoregional recurrence-free survival rate was 80.5% for those who received adjuvant radiation therapy and 28.1% for those who did not (p<0.001). The 15-year distant metastasis-free survival rate was 48.8% for those who received adjuvant radiation therapy and 33.4% for those who did not (p=0.906). The 15-year overall survival rate was 69.7% for those who received adjuvant radiation therapy and 53.1% for those who did not (p=0.921). CONCLUSIONS: Adjuvant radiation therapy ensured favorable locoregional recurrence-free survival in patients with rT4/N1b PTC and might contribute to improving patients' quality of life by reducing the need for additional salvage surgery and the economic burden of other salvage treatments, such as surgery or radioactive iodine therapy.

Clinical impact of radioactive iodine dose selection based on the number of metastatic lymph nodes in patients with papillary thyroid carcinoma: A multicenter retrospective cohort study.

OBJECTIVE: The aim of this study is to investigate whether the number of metastatic lymph nodes (LNs) could be used as a basis in the radioactive iodine (RAI) dose selection for patients with papillary thyroid carcinoma (PTC). PATIENTS: A total of 595 patients with PTC who received first RAI therapy after total or near-total thyroidectomy and had no evidence of disease in treatment response assessment were retrospectively enroled from five hospitals. The patients were classified into two subgroups based on the number of metastatic LNs (>5). The multivariate Cox-proportional hazard model was performed to identify the significant factors for recurrence prediction in each group as well as all enroled patients. RESULTS: Overall, 22 (3.7%) out of 595 patients had the recurrent disease during the follow-up period. The number of metastatic LNs (>5) was only a significant factor for recurrence prediction in all enroled patients (odds ratio: 7.834, p < .001). In the subgroup with ≤5 metastatic LNs, the presence of extrathyroidal extension was only associated with recurrence (odds ratio: 7.333, p = .024) in multivariate analysis. RAI dose was significantly associated with recurrence rate in which the patients with high-dose RAI (3.7 GBq or higher) had less incidence of recurrence than those with low-dose RAI (1.11 GBq) in the subgroup with more than five metastatic LNs (odds ratio: 6.533, p = .026). CONCLUSIONS: High-dose RAI (≥3.7 GBq) therapy significantly lowered the recurrence rate in patients with more than five metastatic LNs. Therefore, RAI dose should be determined based on the number of metastatic LNs as well as conventional risk factors.

Is Postoperative Adjuvant Radioactive Iodine Ablation Therapy Always Necessary for Intermediate-Risk Papillary Thyroid Cancer Patients With Central Neck Metastasis?

BACKGROUND: Papillary thyroid cancer (PTC) is commonly associated with neck lymph node metastasis (LNM), and recurrence does occur after radioactive iodine (RAI) ablation therapy. This study aimed to analyze the effectiveness of RAI ablation with regard to disease recurrence in intermediate-risk PTC patients with neck LNM. In addition, the study identified possible predisposing risk factors that might benefit from RAI ablation and analyzed common RAI therapy complications among these patients. METHODS: A retrospective analysis of 349 intermediate-risk PTC patients with neck LNM who underwent thyroidectomy with neck dissection was performed. The oncologic results and clinicopathologic characteristics of these patients together with the incidence of postoperative RAI therapy complications were evaluated. RESULTS: Of the 349 patients, disease recurrence after treatment occurred for 27 patients (8%) during a mean follow-up period of 58.7 months (range 7-133 months). The recurrence-free survival curve of the patients who received postoperative RAI therapy (n = 208) did not differ significantly from that of the patients who did not receive it (n = 141) (P = 0.567). Nine patients without adjuvant RAI therapy (6%, 9/141) had recurrence. The recurrence rate for the central LNM patients without RAI therapy was only 2% (2/106). Both of these patients with recurrence had pathologic extranodal spread (ENS) and a high number (> 5) of metastatic central LNs. Postoperative RAI-related complications were observed in 24 patients (12%). CONCLUSIONS: Postoperative RAI is not necessary for intermediate-risk papillary thyroid cancer patients with central LNM, especially for patients with negative ENS and low number (< 5) of metastatic lymph nodes.

Can patients with papillary thyroid carcinoma and low postoperative thyroglobulin in the presence of clinically apparent lymph node metastases (cN1) be spared from radioiodine?

BACKGROUND: The study evaluated the recurrence rate in patients with papillary thyroid carcinoma (PTC) and clinically apparent lymph node metastases (LNM) (cN1) who had low thyroglobulin (Tg) after total thyroidectomy and who were not submitted to adjuvant therapy with 131I. METHODS: This was a prospective study. It included 82 cN1 patients (≤3 LNM ≤1.5 cm without macroscopic extracapsular extension) with tumors ≤4 cm without macroscopic extrathyroid invasion (T1-2) and who after thyroidectomy had unstimulated Tg (u-Tg) < 0.3 ng/ml, negative antithyroglobulin antibodies (TgAb), and neck ultrasonography (US) showing no anomalies. The patients were not submitted to therapy with 131I. RESULTS: The time of follow-up ranged from 24 to 156 months (median 84 months). Seventy-nine patients (96.3%) continued to have u-Tg < 0.3 ng/ml and negative US. Three patients (3.6%) exhibited an increase in Tg and structural recurrence was detected in two. After treatment, these patients achieved u-Tg < 1 ng/ml and the imaging methods revealed no apparent tumor. CONCLUSIONS: The results suggest that even cN1 patients, given the absence of extensive LNM or other adverse findings, who have low Tg and neck US showing no anomalies after thyroidectomy do not require radioiodine.

De-differentiation of papillary thyroid carcinoma into squamous cell carcinoma in an elderly patient: A case report.

RATIONALE: The unpredictability of thyroid cancer can be striking, as the disease may rapidly progress to death in some individuals. Herein, we reported a rare case of aggressive papillary thyroid cell carcinoma (PTC) in an elderly patient de-differentiated into squamous cell carcinoma (SCC). PATIENT CONCERNS: We describe a case of a 79-year-old Thai woman presented with hoarseness and neck mass for 2 months and she had been diagnosed with a 3-cm papillary thyroid carcinoma (PTC) in the right side of the thyroid gland. Later on PTC de-differentiated into SCC within 3 years after initial presentation. DIAGNOSIS: De-differentiation from papillary thyroid carcinoma to squamous cell carcinoma. INTERVENTIONS: The patient underwent a total thyroidectomy at the initial hospital and received high dose radioactive iodine (RAI) treatment at our hospital 1 month following the surgery and then was lost to follow-up. Two years later she came back with new development of right solid-cystic neck mass which was found to be recurrent PTC. A radical neck dissection was done and another high dose RAI treatment was given. However, she developed recurrent mass with tenderness at the site above previous solid cystic mass 6 months later. Re-exploration of the neck mass revealed an inflamed midline mass 2 cm with enlarged right lateral cervical lymph nodes. OUTCOMES: A histopathological examination of the midline neck mass showed poorly differentiated SCC with lymphatic invasion. The intermingling of two morphologically distinct tumors, a typical PTC and a poorly differentiated SCC, had been identified in 1 out of 14 excised cervical lymph nodes. The patient underwent external beam radiation without chemotherapy. She is still in stable condition at 18 months post-treatment. LESSONS: This case clearly demonstrated that SCC transformed from a pre-existing PTC. The clinician should consider a possible transformation of papillary thyroid cancer into more aggressive histological types in elderly patients who present with rapidly progressive clinical behavior. However, some patients could have long-term survival if the tumor did not transform into anaplastic thyroid cancer.

Role of adjuvant therapy with radioactive iodine in patients with elevated serum thyroglobulin after neck reoperation due to recurrent papillary thyroid cancer: a monoinstitutional comparative study.

BACKGROUND: Most patients with papillary thyroid cancer (PTC) and lymph node metastases (LNM) undergoing reoperation do not show apparent disease after this procedure, but serum thyroglobulin (Tg) continues to be elevated in part of them. This study evaluated adjuvant therapy with 131I in these patients. METHODS: Patients with PTC and LNM diagnosed after initial therapy were selected. Patients undergoing reoperation and those without apparent disease after this procedure, but with nonstimulated Tg ≥1 ng/ml 6 months after reoperation, were included. The first 25 patients were submitted to therapy with 131I (groups A) and the subsequent 30 patients did not receive this therapy (group B). RESULTS: Groups A and B were similar. During further follow-up, 21 patients developed structural disease and 34 continued without detectable disease (eight achieved complete remission). The outcomes were similar in groups A and B. Patients with Tg reduction >50% after reoperation tended to have a lower risk of recurrence (22.7 versus 48.5%), notably distant metastases (0 versus 15.1%), and were more likely to achieve complete remission (28 versus 3%). Patients with LNM FDG-positive had a higher risk of recurrence (54.5 versus 11.7%) and were less likely to achieve complete remission (3 versus 29.4%) after reoperation. CONCLUSION: Our results suggest that therapy with 131I apparently does not prevent recurrences among patients who continue to have elevated Tg after neck reoperation. Further studies involving these patients are necessary, especially those who are at high risk of recurrence.

Radioprotective Effects of Amifostine, L-Carnitine and Vitamin E in Preventing Early Salivary Gland Injury due to Radioactive Iodine Treatment.

OBJECTIVE: Standard treatment of differentiated thyroid cancer includes total thyroidectomy and high-dose Radioactive Iodine Therapy (RIT) for ablation of remnant thyroid tissue. When administered systemically, RIT can cause radiation-induced damage in non-targeted normal tissues. The aim of the present study was to compare the protective effects of amifostine (AMI), LCarnitine (LC), and Vitamin E (EVIT) against high dose radioactive iodine treatment induced Salivary Gland (SG) damage using SG scintigraphy and histopathological examination. METHODS: Forty adult guinea pigs were studied. Twenty guinea pigs receive 555-660 MBq 131Iodine intraperitoneally (IP) to ablate the thyroid and impair the parenchymal function of the SGs. The animals were divided into eight groups as follows: (1) Group 1 (control): 1 mL IP PS (physiological saline); (2) Group 2: single dose of 200 mg/kg IP AMI one hour prior to 1 mL IP PS; (3) Group 3: 200 mg/kg IP LC and 1 mL IP PS for 10 days; (4) Group 4: 40 mg/kg intramuscular (IM) EVITand 1 mL IP PS for 10 days; (5) Group 5: IP RIT after premedication; (6) Group 6: Single dose of 200 mg/kg IP AMI one hour prior to RIT and IP RIT after premedication; (7) Group 7: IP RIT after premedication and 200 mg/kg IP LC for 10 days starting one day before RIT; and (8) Group 8: IP RIT after premedication and 40 mg/kg IM EVIT for 10 days starting one day before RIT. Scintigraphy was performed 1 month after treatment. SGs were examined by light microscopy and a histopathological scoring system was used to assess the degree of SG damage. RESULTS: There were significant differences in the body weight and thyroid hormone levels between the groups after treatment. CONCLUSION: The individual use of AMI, LC and EVIT for radioprotection yield different levels of protection against radioactive iodine treatment injury in SGs; however, none of the agents could provide absolute protection at the doses administered in this experimental model.

Management of differentiated thyroid carcinomas. / Manejo de los carcinomas diferenciados de tiroides.

INTRODUCTION AND OBJECTIVES: Radioiodine is the principal treatment for differentiated thyroid carcinomas. The aim of this study is to present our experience in the management of these tumours. MATERIAL AND METHOD: We present a retrospective study of 55 patients operated for differentiated thyroid carcinoma in our hospital between 2007 and 2011. RESULTS: The mean age at time of diagnosis was 49 years, and females predominated (78% of cases). Seventy eight percent of the patients were in the initial stages (stages i and ii). The definitive histopathological diagnosis was papillary carcinoma in 84% and follicular carcinoma in the remaining 16%. All of the patients, with the exception of 2 (4%), underwent total thyroidectomy, with lymphadenectomy in 58% of cases. Nine percent of the patients had permanent hypoparathyroidism and although 18% suffered transitory unilateral paralysis, 40% of these female patients had completely recovered after 6 months. Eighty-nine percent of the patients were given radioiodine postoperatively. There was a recurrence rate of 40% most of which was at cervical level (29% of the patients). Survival at 5 years was 87%, 95% of the papillary subtype, falling to 56% of the follicular subtype (P=.001). DISCUSSION/CONCLUSIONS: The prognosis for differentiated thyroid carcinomas is excellent after appropriate surgical treatment, thorough preoperative assessment,and strict postoperative follow-up due to the significant recurrence rates.

30mCi radioactive iodine achieving comparative excellent response in intermediate/high-risk nonmetastatic papillary thyroid cancer: a propensity score matching study.

OBJECTIVE: To determine the efficacy of low-dose radioactive iodine (RAI) therapy (30 mCi, 1110 MBq) in Chinese patients with intermediate- to high-risk papillary thyroid cancer (PTC) without distant metastasis. DESIGN AND METHODS: This large retrospective study included Chinese patients with PTC that tested negative for thyroglobulin antibodies. Patients were categorized into low-dose (30 mCi, 1110 MBq) and high-dose (>100 mCi, 3700 MBq) RAI groups. Ablation rate and long-term response were compared between groups using propensity score matching (PSM) to minimize bias and confounding. RESULTS: In total, we included 446 patients. No significant difference in ablation success rate was found between groups (P = 0.305) before or after PSM (N = 162; P = 0.200). Excellent response (ER) rate was not significant between groups before (P = 0.917) or after PSM (P = 0.798). Efficacy of low-dose RAI was similar to that of high-dose RAI in N0- (P = 1.000), N1a- (P = 0.981), and N1b-stage (P = 0.903) patients. Low- and high-dose RAI groups achieved similar ER rates in pre-ablative stimulated thyroglobulin level (≤1 ng/mL, P = 1.000; 1 < ps-Tg ≤ 5 ng/mL, P = 0.444; 5 < ps-Tg ≤ 10 ng/mL, P = 0.665; >10 ng/mL, P = 1.000) and BRAFV600E-positive (P = 0.324) subgroups. CONCLUSIONS: Efficacy of low-dose RAI therapy was similar to that of high-dose for ablation and achieving ER in Chinese nonmetastatic intermediate- to high-risk PTC patients. High-dose RAI could not rectify ablation failure or non-ER rates in PTC patients with BRAFV600E, lymph node metastases, or unfavorable thyroglobulin levels.

Too Much of a Good Thing: Radioactive Iodine Ablation Use for Micropapillary Thyroid Carcinoma.

Radioactive iodine (RAI) is not routinely recommended for the adjuvant treatment of micropapillary thyroid carcinoma (MPTC). We aimed to report on clinical and pathologic factors associated with the use of RAI in these patients. We queried the Surveillance, Epidemiology, and End Results database for patients who underwent surgery for MPTC (tumor size ≤1 cm) from 1988 to 2009. We excluded patients without a biopsy-proven diagnosis, those diagnosed at autopsy, and patients with documented extra-thyroidal extension. Multivariate logistic regression models predicted the use of RAI based on patient, tumor, and treatment-related factors. We identified 24,076 patients with MPTC that were eligible for study inclusion. Of these, 6,172 (25.6%) received RAI. Lymph node metastases were present in 23.8 per cent of those for whom lymph node status was known. On multivariate analysis, an increasing number of positive nodes, increasing tumor size, Asian race, and male gender predicted the use of RAI. RAI use was less likely in those with advancing age, an increasing number of lymph nodes examined and patients that received less than a total thyroidectomy. Among node-negative patients, Asian race and increasing tumor size predicted the use of RAI. Factors predicting decreased use of RAI were an increasing number of lymph nodes examined, unknown race, less than a total thyroidectomy, and advancing age. A significant number of MPTC patients receive potentially unnecessary RAI.

Central Lymph Node Status has Significant Prognostic Value in the Clinically Node-Negative Tall-Cell Variant of Papillary Thyroid Cancer Regardless of T-Staging and Radioactive Iodine Administration: First Evidence From a Population-Based Study.

BACKGROUND: The prognostic value of central lymph node (CLN) status in papillary thyroid cancer (PTC) remains controversial. This study aimed to provide the first evidence on this issue for the aggressive tall-cell variant (TCV) subtype. METHODS: The study identified TCV patients from the Surveillance, Epidemiology, and End Results database. The Kaplan-Meier method, log-rank test, and multivariate Cox regression models were used for analysis. RESULTS: Of the 744 patients included, 404 were recorded as N0, which were pathologically or only clinically confirmed. Overall survival (OS) and cancer-specific survival (CSS) did not differ significantly between the N0 and pN1a patients (p > 0.05). To investigate the reason, the N0 patients were subdivided according to the number of examined lymph nodes (ELN). The patients with a N0 diagnosis confirmed by two or more ELNs (N0-e2+) showed significantly better outcomes than the pN1a patients and their N0 counterparts without ELN (N0-e0) (p < 0.05), whereas the N0-e0 and pN1a groups demonstrated comparable outcomes in both the log-rank and multivariate analyses (p > 0.05). Moreover, the subgroup analyses showed that even among the patients with early T-staging (T1-T2) or receipt of radioactive iodine (RAI) therapy, the N0-e0 patients still demonstrated compromised OS compared with the N0-e2+ group (p < 0.05). CONCLUSION: The cN0 patients without ELN (N0-e0) had outcomes similar to those of the pN1a patients, but showed a poorer OS than the N0-e2+ group regardless of T-staging and RAI administration, suggesting that occult CLN metastases might act as a negative prognosticator in cN0 TCV. Therefore, prophylactic central neck dissection might be considered for biopsy-proven cN0 TCV patients. Prospective studies are expected to further validate our conclusions.

Fibroelastic pseudotumor elastofibroma dorsi detected by 18F-FDG PET/CT scan and by postherapy radioiodine SPECT/CT. / Seudotumor fibroelástico elastofibroma dorsi detectado por 18F-FDG PET/TC y por 131I SPECT/TC posterapia.

Radioiodine uptake in the thyroid tissue, metastasis of differentiated thyroid cancer (DTC), and in other tissues, depends on the expression of sodium-iodide symporter (NIS). Vascular permeability, effusions, inflammation, and other mechanisms may also play a role in the accumulation of radioactive iodine. A 63-year-old woman underwent radioiodine therapy, as well as a post-therapy whole-body scan, as she was suspected of having lung metastasis from thyroid carcinoma. The scan not only showed uptake at the lung metastasis but also a faint diffuse bilateral uptake in the posterior thorax. On SPECT/CT this uptake was located in a known Elastofibroma Dorsi (ED) previously diagnosed by contrast CT and viewed in a FDG PET/CT. The radioiodine uptake in ED, especially if typical, is not a diagnostic problem in SPECT/CT study, but can be misleading in a study limited to a few planar images, particularly if the uptake occurs asymmetrically, or ED is located in a unsuspected area.

Clinical response to radioactive iodine therapy for prophylactic central neck dissection is not superior to total thyroidectomy alone in cN0 patients with papillary thyroid cancer.

OBJECTIVE: Prophylactic central neck dissection (pCND) is controversial in papillary thyroid carcinoma (PTC) without clinical positive lymph nodes. The aim of this study was to investigate the effect of radioactive iodine (RAI) therapy on the clinical outcome in clinically node-negative (cN0) PTC patients treated with total thyroidectomy (TT) alone or in combination with pCND. PATIENTS AND METHODS: One-hundred and sixty-seven cN0 PTC patients who underwent TT alone (TT) or in combination with pCND (TT+pCND) in our hospital from January 2014 to August 2015 were evaluated retrospectively. Adjuvant RAI therapy was recommended depending on tumor diameter, multifocality, extrathyroidal extension, the presence of positive lymph nodes, and adverse histopathologic features. Serological and imaging data were collected with a mean follow-up of 29.9±5.2 months after RAI administration. Suppressed and stimulated thyroglobulin, thyroglobulin antibody, diagnostic whole-body scintigraphy, and other imaging examinations were used to assess clinical outcome, which was defined as excellent response, indeterminate response, biochemical incomplete response, and structural incomplete response. RESULTS: TT was performed in 62 (37.1%) and TT+pCND in 105 (62.9%). The rate of permanent hypoparathyroidism was significantly higher in TT+pCND than that of TT alone (14.2 vs. 3.2%, P=0.0316). Because of the detection of central neck lymph node metastases by pCND, 42 (40%) patients developed higher recurrence risk stratification (from low to intermediate) and 12 (11.4%) patients were upstaged in TNM staging. RAI therapy was performed for 46 (74.2%) patients in the TT group and 87 (82.9%) in the TT+pCND group. The mean dose for patients receiving RAI in the TT+pCND group was significantly higher than that in the TT group (113.9±23.1 vs. 93.9±18.1, P<0.0001). No significant difference in response to RAI therapy was found between the TT group and the TT+pCND group (P=0.9474). CONCLUSION: Although the addition of pCND to TT, with a concomitant higher frequency of permanent hypoparathyroidism, upstages 40% of patients, thereby changing the dose of RAI therapy, the clinical response to RAI therapy for TT+pCND is not superior to TT alone in cN0 PTC patients.

Chinese Data of Efficacy of Low- and High-Dose Iodine-131 for the Ablation of Thyroid Remnant.

BACKGROUND: Chinese data on the efficacy of low- and high-dose radioiodine for thyroid remnant are still absent. The aim of the study was to investigate whether a low dose of radioiodine is as effective as a high dose for remnant ablation in Chinese patients. METHODS: Patients presenting for radioiodine ablation in the authors' department were included. Inclusion criteria were aged ≥16 years, total or near-total thyroidectomy, tumor-node-metastasis (TNM) stage of pT1-3, any N stage, and M0. All patients were randomly allocated to either the high-dose group of 3700 MBq or the low-dose group of 1850 MBq for remnant ablation. The response to treatment was defined as successful or unsuccessful after a six- to nine-month interval. Ablation was considered to be successful if patients fulfilled the following criteria: no tracer uptake in the thyroid bed on diagnosis whole-body scanning and a negative level of serum thyroglobulin. RESULTS: There were 327 patients enrolled between January 2013 and December 2014. More than 95% had papillary thyroid cancer. Data could be analyzed for 278 cases (Mage = 44 years; 71.6% women), 155 in the low-dose group and 123 in the high-dose group. The rate of initial successful ablation was 84.2% in all patients, 82.6% in the low-dose group, and 86.2% in the high-dose group. There was no difference between the two groups (p = 0.509). CONCLUSIONS: In Chinese patients with differentiated thyroid carcinoma, the low dose of 1850 MBq radioiodine activity is as effective as a high dose of 3700 MBq for thyroid remnant ablation.

Comparison of Survival Outcomes Following Postsurgical Radioactive Iodine Versus External Beam Radiation in Stage IV Differentiated Thyroid Carcinoma.

BACKGROUND: There is a lack of well-powered data regarding outcomes in stage IV differentiated thyroid carcinoma (DTC) treated with postsurgical radiation. The objective of this study was to examine survival in patients with stage IV papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) who received radioactive iodine (RAI), external beam radiation therapy (EBRT), or neither following surgery. METHODS: In this retrospective cohort study, data collected from the National Cancer Data Base (NCDB) yielded 11,832 patients with stage IV DTC who underwent primary surgical treatment between 2002 and 2012. Patients were stratified by histology and sub-stage. Fully parametric, multilevel survival-time models were used to evaluate survival outcomes in three adjuvant treatment groups: RAI, EBRT, or no adjuvant radiation. Hazard ratios (HR) and time ratios (TR) were calculated against patients who did not receive radiation. All models were adjusted for demographic and clinical factors. RESULTS: The mean age of all patients was 61.6 years (SD = 11.6), and 57.5% were female. Patients who received EBRT had significantly higher 5- and 10-year hazards of death in several PTC sub-stages (10-year HRPTC Stage IV-A = 2.12 [confidence interval (CI) 1.79-2.52]; HRPTC Stage IV-B = 2.03 [CI 1.33-3.10]). For stage IV-B PTC requiring EBRT, lifespan after diagnosis was shortened by a factor of 3 when compared to patients who did not receive radiation (TRPTC Stage IV-B = 0.32 [CI 0.16-0.62]). In contrast, RAI was significantly associated with improved 5- and 10-year survival in both PTC and FTC patients regardless of pathological sub-stage. Large reductions in mortality were observed in patients with FTC who were treated with RAI (HRFTC Stage IV-C = 0.19 [CI 0.06-0.65]). When patients with stage IV-C FTC were treated with RAI, life-span after diagnosis doubled (TRFTC Stage IV-C = 1.98 [CI 1.31-3.00]). CONCLUSIONS: Through the NCDB, this study sought to describe prognosis and survival for adjuvant radiation in stage IV DTC. RAI was associated with improved survival for stage IV DTC. Despite treatment benefits conferred by adjuvant EBRT, indications to treat with EBRT were associated with poorer survival outcomes in patients with advanced-stage DTC, particularly PTC.

The Impact of Pathologically Positive Lymph Nodes in the Clinically Negative Neck: An Analysis of 39,301 Patients with Papillary Thyroid Cancer.

PURPOSE: Management of patients with low-risk papillary thyroid cancer (PTC) with clinically uninvolved lymph nodes (cN0 LNs), but who harbor metastatic central LNs (pN1a), remains unclear. The number of central LNs examined, radioactive iodine (RAI) utilization, and survival were compared across cN0 patients based on pN stage: pN0 (negative) versus pNx (unknown) versus pN1a (pathologically positive). METHODS: Adults with a PTC ≥1 cm who were cN0 preoperatively were compared based on surgical pathology using the National Cancer Data Base (NCDB; 2003-2011), after univariate and multivariate adjustment. Overall survival (OS) was examined using Kaplan-Meier curves, the log-rank test, and Cox proportional hazards modeling. RESULTS: Overall, 39,301 patients were included; median tumor size was 1.9 cm. More LNs were examined for pN1a versus pN0 diagnosis (pN1a median = 5 LNs vs. pN0 median = 2 LNs; p < 0.0001), with a median of two central LNs found to be positive on surgical resection. Compared with pN0, pN1a patients were 78% more likely to receive RAI (odds ratio 1.78, 95% confidence interval [CI] 1.65-1.91; p < 0.0001). After adjusting for receipt of RAI, no difference in OS was observed for pN1a versus pN0 or pNx patients (p = 0.72). Treatment with RAI was associated with improved OS (hazard ratio 0.78, 95% CI 0.62-0.98, p = 0.03), but the effect of RAI did not differ based on pN stage (interaction p = 0.67). CONCLUSION: More LNs were examined for positive versus negative pN diagnosis in patients with cN0 PTC. Unsuspected central neck nodal metastases in cN0 PTC patients are associated with increased RAI utilization, but no survival difference.

Practice patterns among thyroid cancer surgeons: implications of performing a prophylactic central neck dissection.

BACKGROUND: Indications for performing a prophylactic central neck dissection (pCND) in papillary thyroid cancer (PTC) remain controversial. It is unclear how identification of lymph node (LN) metastases should impact the decision to treat with radioactive iodine (RAI). The goals of this study were to identify indications for performing pCND and identify factors that predict the use of adjuvant RAI. METHODS: This was a population based cross-sectional analysis. A prospectively collected database identified 594 patients who underwent total thyroidectomy +/- CND. A multivariate model was constructed to identify indications for pCND and predictors of the use of RAI. RESULTS: 425 CNDs were performed of which 224 were prophylactic. Conventional risk factors (age, tumor size, extra-thyroidal extension) were not associated with performing a pCND. The presence of clinically suspicious lymphadenopathy was the only factor associated with performing CND, thus rendering the CND therapeutic. Positive LNs were retrieved in 39 % of pCND's, upstaging 87 patients. Among all peri-operative predictors of receiving RAI, presence of LN metastases was the strongest predictor [OR = 5.9 (3.7-9.5)], while tumor size was a modest predictor [OR = 1.8 (1.5-2.1)]. Other conventional risk factors did not predict use of adjuvant RAI. CONCLUSIONS: Conventional risk factors were not indications for performing a pCND, implying that the decision was based on individual surgeon preference. Performing pCND upstaged 39 % of patients from cN0 to pN1a, increasing the likelihood of receiving RAI 6-fold. Conventional risk factors were not predictors of receiving adjuvant RAI. This highlights the need for a unified approach to performing a pCND and administering RAI.