A Rare False-Positive Whole-Body Scan in a Patient With Differentiated Thyroid Cancer: Unilateral Conjunctival Concretions

ABSTRACT

131 I has been used effectively over the years in both diagnosis and therapy of differentiated thyroid cancer (DTC). Although whole-body scan with 131 I is a highly sensitive tool for detecting normal thyroid tissue and metastasis of DTC, it is not specific; therefore, false-positive images can be seen in clinical practice, and their recognition is critical for correct management. Evaluation of false-positive uptake is important because it may be confused with metastatic involvement. Here, we present a rare false-positive result of whole-body scan in a patient with DTC. To our knowledge, it is the first report on 131 I uptake of conjunctival concretions.

The effect of COVID-19 pandemic restrictions on the management of differentiated thyroid cancer in Turkey: a single tertiary centre experience

PURPOSE

Many countries have implemented unprecedented health measures since the World Health Organisation declared the novel coronavirus disease 2019 (COVID-19) a global pandemic. These measures have resulted in delays in the diagnosis of differentiated thyroid cancer (DTC). However, there is limited data on the impact of restrictions imposed during the pandemic on DTC management. Thus, the aim of this study is to analyse the clinicopathological and follow-up data of DTC patients diagnosed before and during the COVID-19 outbreak.

METHODS

This retrospective study included 191 DTC patients that were diagnosed between December 2018 and June 2021. The patients were divided into two groups: patients diagnosed before (December 2018 to February 2020) and during (March 2020 to June 2021) the COVID-19 pandemic. The clinicopathological and follow-up data between the two groups were compared.

RESULTS

Similar preoperative cytology results were obtained from the two groups. No difference with regard to tumour size, lymphovascular invasion and extrathyroidal invasion was observed between the two groups. While the American Thyroid Association risk stratification was similar between the two groups, radioactive iodine (RAI) therapy was applied less during the COVID-19 period. Although RAI therapy was administered at a lower rate during the COVID-19 period, the recurrence rates among patients after two years of follow-up were similar to those during the pre-COVID-19 period.

CONCLUSION

Although the COVID-19 pandemic restrictions during the pandemic period caused difficulties in the management of DTC patients, this did not negatively affect their prognosis. These findings can confirm the applicability of active surveillance in DTC patients and may help change the real-life treatment practices in selected low-risk DTC patients.

Characterizing Genetic Alterations Related to Radioiodine Avidity in Metastatic Thyroid Cancer

CONTEXT

Patients with differentiated thyroid cancer (DTC) with distant metastasis (DM) are usually not recognized as radioactive iodine (RAI)-refractory DTC in a timely manner. The elucidation of genetic features related to RAI uptake patterns may shed light on the early recognition of RAI-refractory DTC.

OBJECTIVE

This work aimed to elucidate the underlying molecular features behind different RAI uptake patterns.

METHODS

A total of 214 patients with DM-DTC were retrospectively included in the analysis. RAI uptake patterns were defined as initially RAI refractory (I-RAIR) and initially RAI avid (I-RAIA) according to the first post-treatment scan, then I-RAIA was further divided into continually RAIA (C-RAIA), partly RAIR (P-RAIR), and gradually RAIR (G-RAIR) according to subsequent scans. The molecular subtype groups-BRAFV600E mutated, RAS mutated, fusions, and others-were classified according to main driver genes status.

RESULTS

BRAF, TERT promoter, and TP53 mutations are more frequently detected in the I-RAIR pattern while RET fusions and RAS mutations are more frequent in the I-RAIA pattern. A late-hit mutation including TERT, TP53, or PIK3CA is more common in I-RAIR than that in I-RAIA (50.0% vs 26.9%, P = .001), particularly for those with RAS mutations in the I-RAIR group, always accompanied by TERT promoter. Isolated RET fusions accounts for 10% of I-RAIR. When compared among driver gene groups, BRAFV600E-mutated tumors have a higher rate of the I-RAIR pattern (64.4%) than RAS-mutated (4.5%, P < .001) and fusion-positive (20.7%, P < .001) tumors. In I-RAIA subgroups, BRAFV600E-mutated tumors have lower prevalence of the C-RAIA pattern than those with RAS mutation or fusions.

CONCLUSION

Patients with the I-RAIR pattern predominantly featured mutations of the BRAF and/or TERT promoter, of which RAS mutations were usually accompanied by late-hit mutations, while fusions mostly occurred alone.

Management of aggressive variants of papillary thyroid cancer

PURPOSE OF REVIEW

The aim of this study was to provide a timely and relevant review of the latest findings and explore appropriate management of aggressive variants of papillary thyroid cancer (AVPTC).

RECENT FINDINGS

In general, AVPTCs tend to exhibit more invasive characteristics, a lack of responsiveness to radioiodine, increased occurrences of regional spreading, distant metastases and higher mortality rates. Meanwhile, each variant showcases unique clinical and molecular profiles.

SUMMARY

Given the elevated risk of recurrence postsurgery, a more aggressive strategy may be necessary when suspected preoperatively, particularly for those presenting with invasive features. Decision on the extent of surgical treatment and adjuvant therapy is individualized and made by experienced clinicians and multidisciplinary teams based on the clinical presentation, presence of aggressive features and molecular profile. Future studies on development of personalized medicine and molecular target therapy may offer tailored treatment options.

BRAF V600E mutation in papillary thyroid microcarcinoma: is it a predictor for the prognosis of patients with intermediate to high recurrence risk?

OBJECTIVE

The BRAFV600E mutation is the universal genetic mutation in papillary thyroid microcarcinoma (PTMC). The present study is to estimate the role of the BRAFV600E mutation in the clinical outcome of PTMC with intermediate to high recurrence risk after radioactive iodine (RAI) therapy, which is considered to be an indolent tumor.

METHODS

We conducted a single-center retrospective study. Between May 2016 and March 2019, PTMC patients with known BRAFV600E status who received RAI therapy were reviewed at the Second Hospital of Shandong University. Treatment and follow-up were defined according to criteria used in the 2015 ATA guidelines. The association between the BRAFV600E mutation and clinicopathological characteristics, response to RAI therapy, and recurrence after a period of follow-up were analyzed. Propensity score matching (PSM) and logistic regression were used to control confounding variables.

RESULTS

Of the 322 patients with intermediate to high recurrence risk in PTMC, the mean age of the patients were 43.7 ± 12.2 years, and 72.1% were women. BRAFV600E mutation was found in 64.9% (209/322). After PSM, 112 pairs of patients were matched, and except for multifocality (P = 0.001), extrathyroidal invasion (P = 0.003) and tumor size (P = 0.03), there was no significant difference in all baseline characteristics between the two groups. An excellent response (ER) to RAI therapy was observed in 273 patients (84.7%). At the end of the study, 17(5.2%) and 6(1.8%) patients showed structural incomplete response (SIR) and biochemical incomplete response (BIR) status. The proportion of patients who achieved ER status in the BRAFV600E mutation positive and negative groups was 86.6% and 81.4%, respectively. Kaplan-Meier analyses showed that the BRAFV600E mutation was not related to lower ER reached time. The median follow-up was 51 months.

CONCLUSIONS

We found the BRAFV600E mutation was associated with multifocality, extrathyroidal invasion, and tumor size in papillary thyroid microcarcinoma. However, the BRAFV600E mutation had no significant association with clinical outcomes in patients with intermediate to high recurrence risk after RAI therapy. Furthermore, the extra-thyroid uptake results and distant metastasis had been proven to be independent factor predicting the clinical response.

REGISTRATION NUMBER

ChiCTR2200062911.

Incidental but Not Insignificant: Thyroid Cancer in Patients with Graves Disease

BACKGROUND

Graves disease is the most common cause of hyperthyroidism in the US. Treatment with antithyroid drugs and radioactive iodine is more commonly used than surgical management with total thyroidectomy (TTx). However, incidentally discovered thyroid cancer (TC) has been described on surgical pathology from patients who underwent surgical treatment of Graves disease, which would be missed with these other treatment strategies. We sought to determine the incidence rate of TC among patients with surgically treated Graves disease.

STUDY DESIGN

We retrospectively reviewed patients with Graves disease who underwent TTx at a single institution from 2011 to 2023. Pathology reports were reviewed for TC. Patient demographics, preoperative laboratory and radiological evaluations, preoperative medical management, and surgical outcomes were compared between patients with and without incidental TC.

RESULTS

There were 934 patients, of whom 60 (6.4%) patients had incidentally discovered TC on pathology. The majority (58.3%) of patients had papillary thyroid carcinoma, followed by 33.3% with papillary microcarcinoma. Preoperative ultrasound (US) was obtained in 564 (60.4%) of patients, with 44.3% with nodules, but only 34 (13.7%) of those with nodules had TC on final pathology. Preoperative fine needle aspiration was obtained in 15 patients with TC, and 8 patients (53.3%) were reported as benign lesions, which ultimately had TC on final pathology. There was no difference in sex, race or ethnicity, preoperative medical management, and postoperative outcomes between the 2 groups.

CONCLUSIONS

Incidental TC was found on surgical pathology in 6.4% of patients undergoing TTx for Graves disease. Preoperative imaging with US and fine needle aspiration were often unreliable at predicting TC. The incidence of TC should not be underestimated when counseling patients on definitive management for Graves disease.

Tyrosine kinase inhibitors for radioiodine refractory differentiated thyroid cancer: A systematic review and meta-analysis

BACKGROUND

The poor overall prognosis of radioiodine refractory thyroid cancer is an inevitable challenge in managing this disease. A series of trials have demonstrated the antitumor activity of tyrosine kinase inhibitors (TKIs) in radioiodine refractory differentiated thyroid cancer (RAIR-DTC). However, the available evidence cannot determine the optimal choice of TKI in RAIR-DTC.

METHODS

This study searched PubMed, EMBASE, Cochrane databases, and the ClinicalTrials website. The Cochrane bias risk tool was used to assess the risk of bias, and to evaluate randomized clinical trials (RCT) of RAIR-DTC patients treated with the TKI system. Outcomes, including progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were reported.

RESULTS

Seven studies involving 1310 patients with RAIR-DTC was conducted to compare the PFS and OS of various TKI monotherapies with placebo. The results showed that all TKI monotherapies had a statistically significant benefit in terms of PFS compared with placebo, with lenvatinib demonstrating the greatest benefit (hazard ratio [HR] 0.19, 95% credible interval [CrI] 0.14-0.25). In terms of OS, only apatinib (HR 0.42, 95% CrI 0.18-0.97) and anlotinib (HR 0.36, 95% CrI 0.18-0.73) showed statistically significant benefits compared with placebo. TKIs also had a higher incidence of AEs of grade 3 or higher compared with placebo. The findings suggest that lenvatinib may be the preferred TKI for the treatment of RAIR-DTC, although its high incidence of AEs should be considered. The results also indicate that TKI treatment may be similarly effective in RAIR-DTC patients with BRAF or RAS mutations and in those with papillary or follicular subtypes of the disease, regardless of prior TKI treatment.

CONCLUSIONS

The results of this meta-analysis suggest that targeted therapy with TKIs may be beneficial for patients with radioiodine-refractory advanced or metastatic differentiated thyroid cancer. Among the TKIs analyzed, lenvatinib appeared to be the most effective at improving PFS, although it also had the highest incidence of AEs. Further research through direct randomized controlled trials is needed to determine the optimal choice of TKI for treating patients with RAIR-DTC. This study is beneficial for formulating patients' treatment plans and guides clinicians' decision-making.

Radioactive Iodine Therapy of Graves' Disease in Patients Pretreated With Methimazole Without Radioiodine Uptake for Dose Estimation

OBJECTIVE

To assess response predictors to radioactive iodine (RAI) therapy without using thyroid uptake for dose estimate in patients pretreated with methimazole.

METHODS

Retrospective analysis was performed of patients with Graves' disease treated with RAI doses determined without using uptake studies.

RESULTS

In 242 patients (median age, 41.9 years; 66.1% female), initial mean free thyroxine (FT4) level was 4.7 ng/dL with an estimated thyroid size of 49.15 g. Prior to RAI therapy, average methimazole dose was 22.7 mg/day. Mean RAI dose was 737.0 ±199.4 MBq (19.9 ± 5.4 mCi). Two hundred eight patients (85.9%) responded to RAI therapy; 185 (88.9%) became hypothyroid and 23 (11.1%) became euthyroid. The majority (90.4%) responded within 6 months of therapy with a quicker response (13.9 ± 8.3 vs 17.5 ± 13.5 weeks) for those treated with doses per gram of ≥14.8 MBq (0.4 mCi). Thirty-four nonresponders had a higher initial FT4 level and larger thyroid size with a lower RAI dose per gram of thyroid tissue. In multivariate analysis, the independent response predictor to therapy was dose per gram of thyroid tissue of ≥14.8 MBq (0.4 mCi) (hazard ratio, 3.18; 95% CI, 1.1-9.7). Doses per gram of 14.8 to 18.1 MBq (0.4-0.5 mCi) achieved maximal response rate without added advantage of higher doses. Thyroid size prior to RAI therapy, FT4 levels at diagnosis, and age were inversely related to response.

CONCLUSION

RAI therapy for Graves' disease without uptake studies for dose estimates is an effective treatment method. In patients pretreated with methimazole, an RAI dose per gram of thyroid tissue of ≥14.8 MBq (0.4 mCi) showed high response rate. Prospective studies are needed to confirm the viability of this simplified and cost-effective approach.

Ablation Rates and Long-Term Outcome Following Low-Dose Radioiodine for Differentiated Thyroid Cancer in the West of Scotland: A Retrospective Analysis

OBJECTIVE

Low-dose radioiodine is an accepted means of remnant ablation in patients with low- to intermediate-risk differentiated thyroid cancer (DTC) based on the results of several phase III trials. We evaluated the rate of ablation success and long-term recurrence outcomes in the first 3 years of implementing this practice at our institution.

METHODS

Patients who received 1.1 to 1.2 gigabecquerel (30 millicurie) were identified retrospectively from the radionuclide database, January 1, 2012, to December 31, 2014, inclusive. Successful ablation was defined as Iodine-131uptake <0.1% on diagnostic scan and Tg level <2.0 ng/mL at 6 to 8 months after treatment. Follow-up was conducted annually for 10 years and relapse rates were determined based on the available clinical, radiological, and biochemical information.

RESULTS

We identified 114 patients, 109 of whom had dual response assessment. The median age was 43 years (range, 14 to 80 years). Almost 70% had T1 or T2 tumors, with T3 and T4 tumors recorded in 27% and 2.5% of patients, respectively. Nodal staging was performed in just over 30% and involved lymph nodes were detected in 21% (N1a 8% and N1b 13%). Ablation success based on diagnostic scan alone was 94.7% (108/114), Tg alone 94.7% (108/114), and on both modalities was 90.4% (103/114).

CONCLUSION

Remnant ablation was achieved in >90%, and the corresponding clinical recurrence rate was only 1.8% despite the inclusion of patients with locally advanced disease. Low-dose radioiodine is effective and may be suitable for a proportion of patients with higher-risk DTC.

Effects of postoperative antioxidants on the salivary glands in patients with thyroid cancer undergoing radioactive iodine-131 treatment

OBJECTIVE

This study aimed to evaluate the effects of three antioxidants, selenium yeast capsule, vitamin E and vitamin C, alone or in combination, on the salivary glands of patients with differentiated thyroid cancer (DTC) treated with iodine-131 ( 131 I).

METHODS

A total of 69 postoperative DTC patients were randomly divided into three groups: vitamin E combined with vitamin C group (21 cases); selenium yeast group (23 cases); and selenium yeast combined with vitamin C group (25 cases). Salivary gland functional changes were assessed by salivary gland dynamic imaging functional parameters in the enrolled patients before and 1 month after 131 I treatment.

RESULTS

Comparison of salivary gland function parameters before and after 131 I treatment in the three groups were evaluated. In the vitamin E combined with the vitamin C group, the left parotid gland excretion fraction (EF) value was significantly higher than that before treatment. In the selenium yeast group, the left parotid gland excretion part, bilateral parotid gland excretion ratio (ER), left submandibular gland maximum uptake ratio within 20 min (UR20), and the right submandibular gland ER values were significantly higher than that before treatment, while in the selenium yeast combined with vitamin C group, the bilateral parotid gland EF, bilateral submandibular gland UR20, EF, and left submandibular gland ER values were significantly higher than that before treatment (all P  < 0.05).

CONCLUSION

During high-dose 131 I treatment, vitamin E combined with vitamin C improved the excretory function of parotid glands in DTC patients; selenium supplementation had a protective effect on salivary glands; and the combination of selenium and vitamin C had a better effect.

Serum anti-Müllerian hormone is lower in patients with multiple radioiodine dose for treatment of pediatric thyroid cancer

Introduction

Treatment of patients with pediatric differentiated thyroid cancer (DTC) often involves radioiodine (RAI), which is associated with increased risks of short- and long-term adverse outcomes. The impact of RAI treatment on the female reproductive system remains uncertain. Anti-Müllerian hormone (AMH) is a marker of ovarian reserve and is related to fertility.

Objective

The aim was to analyze the association between RAI and serum AMH level in women treated with RAI.

Methods

We evaluated women with pediatric DTC treated with RAI at the age of ≤19 years. Serum AMH was measured.

Results

The study included 47 patients with a mean age of 25.1 years (12.4-50.8) at AMH measurement and follow-up of 11.8 ± 8.4 years. The mean RAI administered was 235 mCi (30-1150). Sixteen (34%) received multiple RAI doses (471 ± 215 mCi). Mean AMH level was 2.49 ng/mL (0.01-7.81); the level was 1.57 ng/mL (0.01-7.81) after multiple RAI doses and 2.99 ng/mL (0.01-6.63) after a single RAI dose (P = 0.01). Patients who received a cumulative RAI lower than 200 mCi had higher AMH levels (2.23 ng/mL, 0.39-7.81) than those who received more (1.0 ng/mL, 0.01-6.63; P = 0.02). In patients with similar cumulative RAI activities, administration of multiple RAI doses was significantly and independently associated with AMH level lower than the reference range for age (HR: 5.9, 1.55-52.2, P = 0.014) after age adjustments.

Conclusion

Levels of AMH were lower after multiple RAI doses, especially after a cumulative RAI dose above 200 mCi. More studies are needed to clarify the impact of RAI on fertility considering its cumulative activity and treatment strategy.

Retrospective case-control study examining the relationship between recurrence-free survival and changes in pre- and post-radioiodine therapy serum thyroglobulin levels in patients with differentiated thyroid cancer

PURPOSE

Thyroglobulin assay is important to assess the residual or recurrence of differentiated thyroid cancer (DTC). Patients with positive serum thyroglobulin levels after radioactive iodine (RAI) adjuvant therapy could achieve long-term recurrence-free survival (RFS). The patient's prognosis could not be confidently estimated based solely on the evaluation of thyroglobulin levels. We investigated the recurrence rate and RFS of patients who received adjuvant RAI therapy after surgery for DTC to clarify the relationship between changes in pre- and post-therapy serum thyroglobulin levels and RFS.

MATERIALS AND METHODS

Patients who underwent adjuvant RAI therapy between May 2007 and March 2021 were included in this study, whereas those with positive anti-thyroglobulin antibodies, distant metastases, or gross residual tumors were excluded. The change in pre- and post-treatment serum thyroglobulin levels under thyroid-stimulating hormone stimulation was calculated and classified as follows: group A, thyroglobulin levels decreased by ˃10%; group B, thyroglobulin levels within a range of 10% or less; and group C, thyroglobulin levels increased by ˃10%. RFS outcomes were analyzed using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test, and multivariate analysis was performed using the Cox proportional hazard model.

RESULTS

A total of 74 patients were included. Relapse was seen in 13 of 46 patients in group A, 9 of 15 in group B, and 10 of 13 in group C. Median RFS was 129.00 (95% confidence interval CI 77.79-180.21), 113.00 (95% CI 86.83-139.17), and 33 months (95% CI 6.026-59.974) in groups A, B, and C, respectively. Patients in group C exhibited significantly shorter RFS than those in groups A and B (P = 0.001).

CONCLUSIONS

Changes in thyroglobulin levels pre- and post-therapy were associated with RFS. Patients with decreased post-therapy thyroglobulin levels had a favorable prognosis, even if their thyroglobulin levels were positive after RAI therapy.

Combined Vorinostat and Chloroquine Inhibit Sodium-Iodide Symporter Endocytosis and Enhance Radionuclide Uptake In Vivo

PURPOSE

Patients with aggressive thyroid cancer are frequently failed by the central therapy of ablative radioiodide (RAI) uptake, due to reduced plasma membrane (PM) localization of the sodium/iodide symporter (NIS). We aimed to understand how NIS is endocytosed away from the PM of human thyroid cancer cells, and whether this was druggable in vivo.

EXPERIMENTAL DESIGN

Informed by analysis of endocytic gene expression in patients with aggressive thyroid cancer, we used mutagenesis, NanoBiT interaction assays, cell surface biotinylation assays, RAI uptake, and NanoBRET to understand the mechanisms of NIS endocytosis in transformed cell lines and patient-derived human primary thyroid cells. Systemic drug responses were monitored via 99mTc pertechnetate gamma counting and gene expression in BALB/c mice.

RESULTS

We identified an acidic dipeptide within the NIS C-terminus that mediates binding to the σ2 subunit of the Adaptor Protein 2 (AP2) heterotetramer. We discovered that the FDA-approved drug chloroquine (CQ) modulates NIS accumulation at the PM in a functional manner that is AP2 dependent. In vivo, CQ treatment of BALB/c mice significantly enhanced thyroidal uptake of 99mTc pertechnetate in combination with the histone deacetylase (HDAC) inhibitor vorinostat/SAHA, accompanied by increased thyroidal NIS mRNA. Bioinformatic analyses validated the clinical relevance of AP2 genes with disease-free survival in RAI-treated DTC, enabling construction of an AP2 gene-related risk score classifier for predicting recurrence.

CONCLUSIONS

NIS internalization is specifically druggable in vivo. Our data, therefore, provide new translatable potential for improving RAI therapy using FDA-approved drugs in patients with aggressive thyroid cancer. See related commentary by Lechner and Brent, p. 1220.

Clinicopathological features of differentiated thyroid carcinoma as predictors of the effects of radioactive iodine therapy

BACKGROUND

Patients with differentiated thyroid cancer (DTC) usually have an excellent prognosis; however, 5 %-15 % develop radioactive iodine-refractory (RAIR) DTC (RAIR-DTC), which has a poor prognosis and limited treatment options. The aim of the present study was to investigate the clinicopathological characteristics of RAIR-DTC in order to provide clinical evidence for timely prediction of the effects of iodine therapy.

METHODS

Clinicopathological data for 44 patients with RAIR-DTC and 50 patients with radioiodine-avid DTC (RAIA-DTC) were retrospectively analyzed. The risk factors for RAIR-DTC were evaluated and a RAIR-DTC prediction model was established.

RESULTS

RAIR-DTC showed unique clinicopathological features that differed from those of RAIA-DTC; these included age >55 years, a high-risk histological subtype, a large tumor size, a late TNM stage, calcification, distant metastasis, and more than six metastatic lymph nodes. Patients with RAIR-DTC also developed earlier tumor progression. Binary logistic regression analysis showed that distant metastasis, a high-risk histological subtype, and a maximum tumor diameter of ≥12.5 mm were independent risk factors for RAIR-DTC, and the specificity and sensitivity of a combination of these three parameters for the prediction of RAIR-DTC were 98.0 % and 56.8 %, respectively. Decision curve analysis and the calibration curve revealed that the combined prediction of these three parameters had good repeatability and accuracy.

CONCLUSION

The clinicopathological features of DTC can effectively predict the effects of iodine therapy. A combination of distant metastasis, a high-risk histological subtype, and a maximum tumor diameter of ≥12.5 mm showed significantly higher prediction accuracy.

Summary and update on the management of differentiated thyroid cancer in 2023

The 6-fold increase in the incidence of differentiated thyroid cancer over the past 30 years in industrialized countries can be mainly attributed to improved detection. At the same time, in addition to the excellent prognosis for low-risk cancers, improved survival in metastatic forms has been also reported, likely due to the progress made recently in the treatment of aggressive forms, for which there is now an extensive therapeutic arsenal. Today, clinical management of differentiated thyroid cancer represents a paradigm of precision oncology, with personalized, risk-adapted therapeutic strategies. This has led to therapeutic de-escalation in those forms with a good prognosis, while targeted treatments play an increasingly important role in the management of radioiodine-refractory or advanced cancers. While endocrinologists will not always have the opportunity to prescribe these treatments, they will be called on to support and monitor patients during treatment. The aim of this article is to provide an overview of treatment options for differentiated thyroid cancer in 2023.

The Accomplishments and Legacy of Saul Hertz, MD

The early history of the use of radioactive iodine (RAI) is complicated and interesting, and also difficult to discover, especially since several histories have presented inaccurate content. This article is a comprehensive review of the accomplishments of Saul Hertz. Extensive use of primary-source verification has clarified several issues, including the question of whether Hertz alone conceived and asked the pivotal question: "Could iodine be made radioactive artificially?"; on what date RAI was first used to treat hyperthyroidism; and why 2 articles on the first use of RAI for treatment of hyperthyroidism, from 2 different sets of authors from the same department of the same institution, appeared adjacent to each other in the same issue of the Journal of the American Medical Association in 1946. Our review also chronicles several major challenges that Hertz overcame to produce his pivotal work. Hertz was clearly the originator and a visionary of RAI therapy in benign and malignant thyroid disease. We believe he can be considered one of the fathers of nuclear medicine. Hertz's paradigm-changing work was a pivotal medical discovery of the 20th century. The legacy of Hertz continues while the application of RAI therapy continues to evolve. RAI therapy remains the preferred treatment in most situations for autonomous nodules and toxic multinodular goiter and remains a safe and effective treatment for Graves disease after more than 80 y of global clinical use. RAI treatment of differentiated thyroid cancer remains a first-line treatment for most patients after surgery, especially for those with intermediate- or high-risk disease.

Diffuse Bone Uptake of 131 I and Effect on Blood Counts in a Patient With Papillary Thyroid Carcinoma and Chronic Lymphocytic Leukemia

ABSTRACT

A 57-year-old woman with history of chronic lymphocytic leukemia was referred to our center for adjuvant 131 I therapy following complete thyroidectomy for differentiated thyroid cancer. Posttherapeutic scintigraphy revealed atypical diffuse osteomedullar uptake. A major drop in lymphocyte count was observed, from 117.7 g/L to 4.8 g/L 8 weeks after 131 I therapy. Bone marrow uptake is presumed to be related to tracer sequestration in leukemic cells. White blood cell count normalization suggests a high sensitivity of leukemic cells to beta emission. This scintigraphic pattern may act as a pitfall for nuclear medicine physician.

Predictive factors for the outcome of radioiodine therapy in patients with benign thyroid diseases

PURPOSE

Radioiodine therapy (RIT) of benign thyroid diseases is an established therapy. This study aimed to identify factors predictive for outcome in patients with non-toxic goiter (NTG), unifocal (UFA), multifocal (MUFA) or diffuse autonomy (DISA) and Graves' disease (GD).

METHODS

Retrospective analysis of 205 patients with benign thyroid disease (54 NTG, 46 MUFA, 24 DISA, 26 UFA, 55 GD) who underwent RIT. Follow up time was 12 months for determining treatment outcome.

RESULTS

The type of disease was predictive for volume reduction after 12 months (NTS 66%, DISA 67%, MUFA 58%, UFA 51%, GD 71%, p<0.001) and post-treatment hypothyroidism (NTS 48%, DISA 33%, MUFA 15%, UFA 15%, p=0.006). Initial volume, intra-therapeutic uptake and intra-therapeutic half-life were independent prognostic factors for volume reduction 12 months after RIT. In patients with NTG, UFA, MUFA, DISA post-treatment hypothyroidism was significantly correlated with extent of volume reduction 12 months after RIT, achieved dose, higher pre-therapeutic TSH values and younger age. Two different strategies for pre-therapeutic dosimetry used in MUFA showed no differences regarding the therapeutic outcome. In GD, effective half-life, initial volume and Graves' ophthalmopathy were predictive for treatment failure.

CONCLUSION

Reduction of thyroid volume and the percentage of hypothyroid patients one year after RIT was primarily dependent on the type of disease. In MUFA and DISA we could identify volume reduction after 3 months as a reliable predictor for hypothyroidism while in patients with GD a short intra-therapeutic half-life, a large pre-therapeutic volume and active Graves' ophtalmopathy were relevant predictors for treatment failure suggesting an intensified follow-up scheme in these patients.

A New Twist on a Classic: Enhancing Radioiodine Uptake in Advanced Thyroid Cancer

Advanced differentiated thyroid cancer that is resistant to radioactive iodine therapy may become responsive with a unique treatment combination of chloroquine and vorinostat. This treatment was demonstrated in cellular and animal models of thyroid cancer to inhibit endocytosis of the plasma membrane-bound iodine transporter, NIS, and restore iodine uptake. See related article by Read et al., p. 1352.

GRADE-ADOLOPMENT of hyperthyroidism treatment guidelines for a Pakistani context

INTRODUCTION

The prevalence of hyperthyroidism in Pakistan is 2.9%, which is two times higher than in the United States. Most high-quality hyperthyroidism clinical practice guidelines (CPGs) used internationally originate from high-income countries in the West. Local CPGs in Pakistan are not backed by transparent methodologies. We aimed to produce comprehensive, high-quality CPGs for the management of hyperthyroidism in Pakistan.

METHODS

We employed the GRADE-ADOLOPMENT approach utilizing the 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis as the source CPG. Recommendations from the source guideline were either adopted as is, excluded, or adapted according to our local context.

RESULTS

The source guideline included a total of 124 recommendations, out of which 71 were adopted and 49 were excluded. 4 recommendations were carried forward for adaptation via the ETD process, with modifications being made to 2 of these. The first addressed the need for liver function tests (LFTs) amongst patients experiencing symptoms of hepatotoxicity while being treated with anti-thyroid drugs (ATDs). The second pertained to thyroid status testing post-treatment by radioactive iodine (RAI) therapy for Graves' Disease (GD). Both adaptations centered around the judicious use of laboratory investigations to reduce costs of hyperthyroidism management.

CONCLUSION

Our newly developed hyperthyroidism CPGs for Pakistan contain two context-specific modifications that prioritize patients' finances during the course of hyperthyroidism management and to limit the overuse of laboratory testing in a resource-constrained setting. Future research must investigate the cost-effectiveness and risk-benefit ratio of these modified recommendations.

Apathetic Graves' disease with severe hepatic and renal dysfunction induced by COVID-19 infection: Case report and literature review

RATIONALE

A rare and intractable case of apathetic Graves' disease (GD) with severe liver and kidney damage induced by coronavirus disease 2019 (COVID-19) carries a certain risk of missing diagnosis and delayed treatment during the COVID-19 pandemic.

PATIENT CONCERN

A 60-year-old female patient developed anorexia, exhaustion, jaundice, nausea, and vomiting 10 days after COVID-19 infection. She was admitted to the Infectious Diseases Department because of recurring symptoms for more than a month.

DIAGNOSIS

Based on the patient's epidemiological history, clinical symptoms, and prior history, she was preliminarily diagnosed with GD induced by COVID-19 with severe hyperthyroid-related liver injury and chronic kidney disease stage 4. Drug-induced and radiation-induced liver injuries occurred sequentially throughout the therapy.

INTERVENTION

Methimazole (MMI) (10 mg/d) was administered for 1 week, and the patient's symptoms, thyroid function, and liver and kidney function improved. Nevertheless, the aforementioned symptoms and liver and kidney function deteriorated 20 days after increasing the MMI dose (20 mg/d). Therefore, in the presence of an artificial liver, hemodialysis, and other medical conditions, the treatment schedule was adjusted to individualized 131I anti-hyperthyroidism therapy.

OUTCOME

After 131I treatment, the patient's liver function returned to almost normal levels after a month, but worsened when the hepatoprotective drugs were stopped. Renal function did not deteriorate significantly and returned to baseline after 3 months. Thyroid function was restored to normal approximately 4 months later.

CONCLUSION

COVID-19 may induce GD. Multidisciplinary collaboration can be initiated as early as possible. Individualized 131I therapy or long-term low-dose MMI (10 mg/d) can be considered to manage hyperthyroidism in GD patients with liver and kidney dysfunction and to prolong liver protection therapy appropriately.

False diagnosis of recurrent thyroid carcinoma: the importance of testing for heterophile antibodies

Thyroglobulin (Tg) levels are important to predict recurrence in differentiated thyroid cancer patients.However, false-positive results can hence the request of unnecessary tests and treatments. We reported two cases of interference in thyroglobulin measurement and the workup to investigate them. Both patients achieved an excellent response to therapy after total thyroidectomy and one patient had also received radioiodine treatment. During the follow-up, Tg levels increased and there was no evidence of recurrent disease in the imaging studies. The Tg levels by the Access platform were positive but the results by Elecsys platform and LC-MS/MS were undetectable, leading to the hypothesis of heterophile antibodies (HAbs) interference. The possibility of HAbs interference must be considered when the Tg levels do not fit in the clinical picture. The measurement of Tg by another immunoassay or by LC-MS/MS may be useful in these situations.

Bone loss after discontinuation of denosumab: the devil is in the details

A 47-year-old postmenopausal woman with osteoporosis was treated with denosumab, which was discontinued due to side effects. She was therefore transitioned to a yearly intravenous infusion of zoledronic acid. An increase in bone turnover markers together with bone loss at the lumbar spine was observed before the second infusion, suggesting an overshooting of bone resorption due to denosumab discontinuation. On physical examination, the patient was restless and reported having lost about 10 kg since the last visit. A solitary left inferior thyroid nodule was noted on neck palpation. Circulating thyroid hormone levels were elevated, with suppressed thyroid-stimulating hormone. A thyroid scan showed increased uptake in the left inferior nodule with suppression of the remainder of the thyroid gland. A diagnosis of hyperthyroidism due to toxic adenoma was made. The patient was treated with radioactive iodine ablation, with consequent complete normalization of thyroid function. She continued yearly treatment with zoledronic acid. She remained clinically well with no further fractures. Bone turnover markers were appropriately suppressed and bone mineral density increased in the spine and hip. This case illustrates how the overshooting phenomenon following denosumab discontinuation may be compounded by the development of secondary conditions, which can result in suboptimal response to antiresorptive osteoporosis medications.

MACE and Hyperthyroidism Treated With Medication, Radioactive Iodine, or Thyroidectomy

Importance

Excessive thyroid hormones from hyperthyroidism increase cardiovascular risks. Among 3 available treatments for hyperthyroidism, comparisons of long-term outcomes associated with antithyroid drugs (ATDs), radioactive iodine (RAI), and surgery to treat newly diagnosed hyperthyroidism are lacking.

Objective

To compare risks of major adverse cardiovascular events (MACE) and all-cause mortality among patients with hyperthyroidism treated with ATDs, RAI, or surgery.

Design, Setting, and Participants

This nationwide cohort study used the Taiwan National Health Insurance Research Database. Patients aged 20 years or older with newly diagnosed hyperthyroidism between 2011 and 2020 were enrolled. Treatment groups were determined within 18 months from diagnosis, with follow-up until the development of MACE, death, or the end date of the database, whichever came first. Data were analyzed from October 2022 through December 2023.

Exposures

The ATD group received ATDs only. RAI and surgery groups could receive ATDs before treatment. Anyone who underwent thyroid surgery without RAI was classified into the surgery group and vice versa.

Main Outcomes and Measures

The primary outcomes included MACE (a composite outcome of acute myocardial infarction, stroke, heart failure, and cardiovascular mortality) and all-cause mortality.

Results

Among 114 062 patients with newly diagnosed hyperthyroidism (mean [SD] age, 44.1 [13.6] years; 83 505 female [73.2%]), 107 052 patients (93.9%) received ATDs alone, 1238 patients (1.1%) received RAI, and 5772 patients (5.1%) underwent surgery during a mean (SD) follow-up of 4.4 (2.5) years. Patients undergoing surgery had a significantly lower risk of MACE (hazard ratio [HR] = 0.76; 95% CI, 0.59-0.98; P = .04), all-cause mortality (HR = 0.53; 95% CI, 0.41-0.68; P < .001), heart failure (HR = 0.33; 95% CI, 0.18-0.59; P < .001), and cardiovascular mortality (HR = 0.45; 95% CI, 0.26-0.79; P = .005) compared with patients receiving ATDs. Compared with ATDs, RAI was associated with lower MACE risk (HR = 0.45; 95% CI, 0.22-0.93; P = .03). Risks for acute myocardial infarction and stroke did not significantly differ between treatment groups.

Conclusions and Relevance

In this study, surgery was associated with lower long-term risks of MACE and all-cause mortality, while RAI was associated with a lower MACE risk compared with ATDs.

Intraoperative implantation of 125I seeds improves prognosis in refractory stage IIIB cervical cancer: a case report and literature review

BACKGROUND

Concurrent chemoradiation is the standard treatment for advanced cervical cancer. However some patients still have a poor prognosis, and currently, there is no effective treatment for recurrence. In recent years, 125I seed implantation therapy has emerged as a treatment for advanced malignant tumors including surgically unresectable tumors, residual tumors after surgical resection, and metastatic tumors. However, the use of 125I seeds implantation in primary advanced cervical cancer has not been reported. In this study, we present a case of stage IIIB cervical cancer in a patient who had poor response to radiotherapy and chemotherapy. Subsequently, a radical hysterectomy was performed, and 125I radioactive seeds were successfully implanted during the surgery. This effectively controlled the lesions that were resistant to radiotherapy and had the potential to improve the prognosis.

CASE PRESENTATION

A 56-year-old woman was diagnosed with stage IIIB (FIGO 2009) IIIC1r (FIGO 2018) squamous carcinoma of the cervix. After receiving 4 cycles of platinum-based chemotherapy and 30 rounds of radiotherapy, she underwent a radical hysterectomy. The localized cervical lesions were reduced, but there was no reduction in the size of the enlarged pelvic lymph nodes. Therefore, 125I seed implantation was performed under direct surgical vision for the right paracervical lesion and the enlarged pelvic lymph nodes on the right side. During the 18-month follow-up period, the enlarged lymph nodes subsided without any signs of recurrence or metastasis.

CONCLUSION

Intraoperative implantation of 125I seeds in lesions that are difficult to control with radiotherapy or in sites at high risk of recurrence is a feasible and effective treatment option for patients with advanced squamous cervical cancer, and it may contribute to improved survival.

Radioactive iodine therapy for follicular thyroid cancer: a 15 years follow-up study of Chinese patients

PURPOSE

To identify long-term predictors of distant metastases (DM) and the overall survival (OS) of follicular thyroid cancer (FTC) patients who underwent radioactive iodine (RAI) therapy. And to expand the knowledge about the clinical course and experience of RAI treatment for FTC.

MATERIALS

A total of 117 FTC patients who underwent RAI therapy at our institution from 2005 to 2020 were retrospectively studied. Patient characteristics, serum stimulating thyroglobulin (sTg) and thyroglobulin antibody levels, treatment process and follow-up data were collected until 26 April 2022.

RESULTS

A total of 16 patients (13.7%) were lost to follow-up. A total of 23 (19.7%) patients with DM died and all FTC without DM were still alive. DM was seen in 58.4% (59/101) of patients. The most common location for metastatic lesions was the lung. Then was bone. The mean survival time of FTC with RAI was 156 months [95% confidence interval (CI): 142-171]. Five-year and 10-year cumulative survival rates of them were 88.8% and 67.4%, respectively. As for patients with DM were 80.4% and 41.3%, respectively. Age at diagnosis [odds ratio (OR) = 1.080, P  = 0.009], RAI therapy sessions (OR = 2.959, P  = 0.001) and sTg level (OR = 1.006, P  = 0.002) were predictive of DM occurrence in FTC with RAI. In the group of FTC with DM, survival analysis showed that males were more likely to have a lower OS than females ( P  = 0.039).

CONCLUSION

Age, number of RAI therapy sessions, and sTg level were predictive of the occurrence of DM in FTC patients with RAI. Sex would influence the OS of FTC patients with DM.

Comparison of body iodine pool assessment methods before radioiodine therapy

INTRODUCTION AND OBJECTIVES

Radioactive iodine therapy (RAIT) is recommended to reduce the risk of recurrence and metastasis in patients with intermediate-high risk differentiated thyroid cancer (DTC). In preparation for RAIT, stimulation of thyroid-stimulating hormone and reduction of body iodine pool are important for treatment success. For this purpose, patients are asked to reduce their iodine intake before RAIT, and the body iodine pool can be evaluated by measuring iodine excretion in urine before treatment. The aim of our study is to compare the methods used to measure the body iodine pool in the evaluation of the restricted iodine diet (RID) effectiveness applied in the RAIT preparation.

PATIENTS AND METHODS

Eighty DTC patients discontinued levothyroxine three weeks before RAIT and followed up with a RID two weeks before treatment. After two weeks of RID, all patients collected their 24-h urine the day before the RAIT date. Patients completed 24-h urine samples on the morning of the RAIT date and also provided a spot urine sample. The estimated 24-h creatinine excretion of the patients was calculated. Estimated 24-h urinary iodine excretion (UIE) was calculated using the spot urine iodine/creatinine (I/C) ratio of the patients. 24-h UIE, iodine concentration in spot urine, I/C ratios in spot urine and estimated 24-h UIE of the patients were analyzed by comparing with each other.

RESULTS

In 99% of the patients, RID efficiency was sufficient according to 24-h UIE before RAIT. The mean 24-h UIE was 48.81 micrograms/day (mcg/day) in 24-h urine samples taken from the patients to evaluate the body iodine pool. The patients' iodine concentrations in spot urine, I/C ratios in spot urine, and estimated 24-h UIE were all statistically significantly lower than actual 24-h UIE, which was the reference method (p: 0.026 vs <0.001 vs 0.041). Moderate positive correlation between 24-h UIE and iodine concentration in spot urine (r: 0.440), I/C ratio in spot urine (r: 0.493), and estimated 24-h UIE (r: 0.560) found. The strongest correlation was obtained with the estimated 24-h UIE.

CONCLUSION

The estimated 24-h UIE obtained by using the I/C ratio in spot urine can be used practically and safely as an alternative to UIE in 24-h urine, which is the gold standard method for evaluating body iodine pool.

A rare case of thyroid carcinosarcoma arising from recurrent papillary thyroid cancer: Case report and review of the literature

BACKGROUND

Thyroid carcinosarcoma represents a rare subtype of thyroid cancer, distinguished by its unique histopathology-simultaneous malignant epithelial and mesenchymal cells. The occurrence of thyroid carcinosarcoma arising from recurrent papillary thyroid cancer is exceptionally infrequent.

METHODS

Study outlines a patient's thyroid carcinosarcoma journey, covering presentation, recurrence, diagnostics, surgeries, and follow-up. A PubMed search gathered data on pathological features and treatment approaches for thyroid carcinosarcoma.

RESULTS

The patient initially diagnosed with papillary thyroid cancer underwent thyroidectomy, neck dissection, and radioactive iodine therapy. Recurrence revealed thyroid carcinosarcoma, featuring papillary carcinoma, squamous cell carcinoma, and spindle cell components. Total laryngectomy followed by adjuvant radiotherapy and chemotherapy. The patient was followed for 17 months with no evidence of disease.

CONCLUSIONS

This extraordinary case exemplifies a rare instance of local relapse in form of thyroid carcinosarcoma following an initial diagnosis of papillary thyroid carcinoma. Surgical resection and chemoradiotherapy show promising outcomes in managing this challenging condition.

Comparison of Recombinant Human Thyroid-Stimulating Hormone and Thyroid Hormone Withdrawal for 131 I Therapy in Patients With Intermediate- to High-Risk Thyroid Cancer : A Systematic Review and Meta-analysis

BACKGROUND

This meta-analysis and systematic review aimed to evaluate the therapeutic efficacy and advantages associated with the use of recombinant human thyroid-stimulating hormone (rhTSH) for radioactive iodine (RAI) therapy in patients with intermediate- to high-risk differentiated thyroid cancer.

PATIENTS AND METHODS

MEDLINE, EMBASE, and Cochrane databases were searched to identify relevant articles reporting clinical outcomes of rhTSH compared with thyroid hormone withdrawal (THW) in patients with intermediate- to high-risk differentiated thyroid cancer published between January 2012 and June 2023. Meta-analyses were performed (PROSPERO registration number: CRD42022340915) to assess the success rate of radioiodine remnant ablation (RRA) in patients with intermediate to high risk and determine the disease control rate among patients with distant metastases, evaluated using the RECIST criteria.

RESULTS

Thirteen studies involving 1858 patients were included in the meta-analysis. Pooled analyses revealed significantly higher overall RRA success rate in the rhTSH group compared with the THW group, with a risk ratio (RR) of 1.12 (95% confidence interval [CI], 1.01-1.25). However, in the subgroup analysis of high-risk patients, pooled analyses showed no significant differences in RRA success rate between the rhTSH group compared with the THW group with a pooled RR of 1.05 (95% CI, 0.88-1.24). In patients with distant metastases, there were no significant differences in the disease control rate between groups, with a pooled RR of 1.06 (95% CI, 0.78-1.44).

CONCLUSIONS

rhTSH for RAI therapy is a practical option for RAI therapy in patients with intermediate- to high-risk thyroid cancer, including those with distant metastases.

Concurrent Benign Iodine-Avid Thymic and Liver Cysts Mimicking Metastatic Disease on 131I Whole-Body Scintigraphy

ABSTRACT

A 57-year-old woman received radioiodine therapy post total thyroidectomy for pT3aNxMx follicular thyroid carcinoma. Posttherapy 131I whole-body scan showed 131I concentration in the chest, mediastinum, and left upper thigh with stimulated thyroglobulin (Tg) of 89 μg/L. Subsequent radioiodine therapies showed persistent 131I accumulation in the anterior mediastinal soft tissue lesions and a hypodense segment VII liver lesion visualized on SPECT/CT, suggestive of iodine-avid metastatic disease despite the undetectable serum Tg (<1.0 μg/L) with no Tg antibody interference. Biopsy of the liver lesion revealed liver cyst, and consequent removal of the mediastinal lesions showed benign thymic cysts.

The Prognostic Power of Preablation Stimulated Thyroglobulin in Children With Differentiated Thyroid Cancer

OBJECTIVE

To analyze prognostic factors in children with differentiated thyroid carcinoma (DTC) who have been treated in a single center in the last 27 years.

METHODS

We studied 126 children (≤18 years old) who have been treated with near-total thyroidectomy followed by radioiodine therapy and thyroid hormone replacement. Follow-up of the patients was done 2, 6, and 12 months after treatment and then by yearly evaluation. Response to treatment was defined according to the American Thyroid Association guidelines.

RESULTS

Papillary thyroid cancer was the main pathology (93.7%), and 52.4% of the patients had lymph node metastasis at presentation, which was extensive (>5) in 30% of the patients. Distant metastasis was seen in 8.8%. The mean initial dose of I-131 was 74 ± 42.2 MBq/kg. The median follow-up was 59 months and the median time to achieve an excellent response was 29 months. The preablation stimulated thyroglobulin (psTg) level was 202.4 ± 301.8 ng/mL in patients with first-year incomplete response compared with 11.2 ± 17.5 ng/mL in others (P =.001). Furthermore, using logistic regression, the psTg level was found to be the only significant predictor of distant metastasis, and psTg ≥ 13.75 ng/mL was the most powerful predictor of first-year incomplete response. Moreover, distant metastasis was more common in boys than in girls, and it took longer time for boys to achieve an excellent response.

CONCLUSION

The psTg level was the only significant predictor of distant metastases in children with DTC, and psTg ≥ 13.75 ng/mL was the most powerful predictor of first-year incomplete response.

Reaching the target dose with one single 131 I-mIBG administration in high-risk neuroblastoma: The determinant impact of the primary tumour

BACKGROUND

131 I-metaiodobenzylguanidine (131 I-mIBG) effectiveness in children with metastasised neuroblastoma (NB) is linked to the effective dose absorbed by the target; a target of 4 Gy whole-body dose threshold has been proposed. Achieving this dose often requires administering 131 I-mIBG twice back-to-back, which may cause haematological toxicity. In this study, we tried identifying the factors predicting the achievement of 4 Gy whole-body dose with a single radiopharmaceutical administration.

MATERIALS AND METHODS

Children affected by metastatic NB and treated with a high 131 I-mIBG activity (>450 MBq (megabecquerel)/kg) were evaluated retrospectively. Kinetics measurements were carried out at multiple time points to estimate the whole-body dose, which was compared with clinical and activity-related parameters.

RESULTS

Seventeen children (12 females, median age 3 years, age range: 1.5-6.9 years) were included. Eleven of them still bore the primary tumour. The median whole-body dose was 2.88 Gy (range: 1.63-4.22 Gy). Children with a 'bulky' primary (>30 mL) received a higher whole-body dose than those with smaller or surgically removed primaries (3.42 ± 0.74 vs. 2.48 ± 0.65 Gy, respectively, p = .016). Conversely, the correlation between activity/kg and the whole-body dose was moderate (R: 0.42, p = .093). In the multivariate analysis, the volume of the primary tumour was the most relevant predictor of the whole-body dose (p = .002).

CONCLUSIONS

These data suggest that the presence of a bulky primary tumour can significantly prolong the 131 I-mIBG biological half-life, effectively increasing the absorbed whole-body dose. This information could be used to model the administered activity, allowing to attain the target dose without needing a two-step radiopharmaceutical administration.

Impact factors of benefiting from initial 131 I ablation in patients with intermediate-risk differentiated thyroid carcinoma: a study based on a re-evaluation of therapeutic response

OBJECTIVE

This study was carried out to confirm whether patients with intermediate-risk differentiated thyroid cancer (DTC) could benefit from initial 131 I ablation and to identify the factors that impacted the benefit.

METHODS

We retrospectively assessed a cohort of 548 patients with intermediate-risk DTC who were classified into structural incomplete response (SIR), biochemical incomplete response (BIR), indeterminate response (IDR), and excellent response (ER) groups according to the ATA guidelines (version 2015). A downgrade in the classification, such as from initial SIR to final BIR, IDR, or ER, from BIR to IDR or ER, and from initial IDR to final ER, was defined as benefiting from initial 131 I ablation (benefit group). Non-downgraded classification meant non-benefit.

RESULTS

64.78% of patients benefited from the initial 131 I ablation in the final re-evaluation. Gender (OR = 0.038, P  = 0.002), interval time (OR = 0.038, P  = 0.002) and serum ps-Tg (OR = 0.961, P  = 0.001) were independent prognostic factors for benefiting from initial 131 I ablation, with the cutoff value were 5 months and 19.08 ng/ml.

CONCLUSION

Patients with intermediate-risk DTC could benefit from initial 131 I ablation. Female patients with intermediate-risk DTC whose interval time <5 months and ps-Tg <19.08 ng/ml were more likely to benefit. Early 131 I ablation for such patients is beneficial for achieving a complete therapeutic response.

Incidence of subclinical and overt hypothyroidism in children treated with [131I]mIBG: a systematic review and meta-analysis

INTRODUCTION

Treatment with [131I]mIBG is commonly used in pediatric metastatic neuroblastoma (NB); however, unbound [131I]I might be taken up by the thyroid, causing hypothyroidism. To prevent this occurrence, thyroid blockade with iodine salts is commonly used; despite this precaution, thyroid dysfunction still occurs. This review and meta-analysis aim to clarify the mean frequency of hypothyroidism in children with NB treated with [131I]mIBG and to investigate the possible causes.

EVIDENCE ACQUISITION

The literature was searched for English-language scientific manuscripts describing the incidence of TSH elevation and overt hypothyroidism in children with NB treated with [131I]mIBG. Preclinical studies, small-case series, and reviews were excluded. A proportion meta-analysis was conducted to test the influence of potentially relevant factors (type and duration of thyroid blockade, year of the study, sample size) on the incidence of TSH elevation/overt hypothyroidism.

EVIDENCE SYNTHESIS

Eleven studies were included. The pooled percentage of TSH elevation was 0.41 (95% CI: 0.27-0.55); the duration of the thyroid blockade (P=0.004) was inversely correlated with the incidence of TSH elevation. Moreover, a TSH increase was more common in patients treated with potassium iodide (KI) alone than in those managed with a multi-drug thyroid blockade (P<0.001). The pooled percentage of children requiring hormone replacement therapy was 0.33 (95% CI: 0.16-0.49). As in the case of TSH elevation, a longer duration of the thyroid blockade (P=0.006) and a multi-pronged approach (P<0.001) were associated with a lower incidence of overt hypothyroidism.

CONCLUSIONS

Hypothyroidism appears to occur frequently in children treated with [131I]mIBG, which should be monitored closely after the radionuclide treatment to start hormone replacement therapy as soon as needed. The duration, as well as the type of thyroid blockade, seem to influence the incidence of hypothyroidism; however, more data from prospective evaluations are needed.

Basal or stimulated thyroglobulin in evaluating response to treatment in papillary thyroid carcinoma? A retrospective cohort study

OBJECTIVE

It is not clear whether response to initial treatment in papillary thyroid carcinoma (PTC) patients is best evaluated by measuring thyroglobulin (Tg) in the presence of levothyroxine (BTg) or when stimulated by elevated TSH (STg). The aim of this study was to evaluate whether response to therapy 1 year after initial treatment changes with the use of STg in relation to BTg in PTC patients treated with total thyroidectomy (TT) and radioiodine (131I), and, if observed, to assess which response is better associated with clinical course.

SUBJECTS AND METHODS

This is a retrospective study of 148 PTC patients submitted to TT and 131I. We analyzed the response to therapy (excellent, biochemical incomplete, or indeterminate) at 1 year after initial treatment, using BTg or STg, and compared which method was better associated with "excellent response at final evaluation."

RESULTS

Twenty-eight patients (20.4%) presented change in response to therapy, with 17 of these (60.7%) presenting a worse response. Response using STg was 1.6 times better associated with proposed outcome [odds ratio (OR) = 4.61; confidence interval 95% (IC95%): 2.13-9.98] than with BTg (OR = 2.84; IC95%: 1.33-6.06).

CONCLUSION

Response to therapy at 1 year using STg was altered in approximately 20% of cases and therefore proved to be a better predictor of excellent response in the last evaluation.

Current approach to pediatric differentiated thyroid cancer

Differentiated thyroid cancers (DTC) is a rare cancer in children and adolescents, having features of different clinical presentation, biological behavior, and treatment from adult population. Most of the patient management guidelines are based on literature on adult population and the literature on children and adolescents still limited. There are still unsettled issues regarding both patient management and the therapy. However, the current approach for treatment of DTC includes thyroidectomy, lymph node dissection in patients with nodal metastases and possible use of Iodine-131 radiotherapy. The incidence of DTC is low in pediatric population, and the characteristics of the disease vary among different age groups within this population. Therefore, the literature depends on small cohorts and heterogeneous retrospective studies. This paper aims to review the current literature and give an overview to the approach in the management of DTC in pediatric population. DTC in pediatric population, has an aggressive nature, however the patient's overall survival is excellent. A multidisciplinary approach in the management of pediatric DTC patients would yield fewer side effects and a better life quality.

Factors predicting remission in hyperthyroid patients after low-dose I-131 therapy: 20 years retrospective study from a tertiary care hospital

OBJECTIVE

To assess the therapeutic outcome and factors predicting remission in hyperthyroid patients treated with low-dose I-131 (radioactive iodine) from a tertiary care hospital in South India.

METHODS

This 20-year single-institutional retrospective study was carried out on 3891 hyperthyroid adult patients. Only those patients with complete clinical records were audited. Selection criteria were based on patients with scintigraphic diagnosis of either Graves' disease (GD), toxic multinodular goitre (TMNG) or autonomous toxic nodule (ATN) and the records of those who received low-dose I-131 therapy (LDT) between March 2000 and 2020 at Amrita Institute, Cochin were analysed. SPSS 10 software was used for statistical analysis.

RESULTS

The records of 3891 hyperthyroid predominantly female patients were analysed. 65% patients had GD, 33% had TMNG and 3% were ATN. High rates of remission as early as 12 weeks (in 61% patients) was observed with a single dose of LDT while on strict iodine-free diet for 3-4 weeks prior to LDT. Study reveals that those with lower free T4 (fT4), small goitre (thyroid volume < 25 cm3), < 15% thyroid trapping function, shorter time duration from onset of hyperthyroidism to LDT, and treatment-naïve patients were factors determining high remission rates. Mann Whitney U test and Chi-square test was used to correlate variables in the remission and relapse groups. We found a positive correlation between fT4, thyroid volume (r = 0.35, p < 0.01) and trapping function (r = 0.34, p < 0.01), which were independent of age, sex, body mass index and TSH levels in our study.

CONCLUSION

High therapeutic outcome was observed with a single dose of LDT while on iodine-free diet. Remission with single dose of LDT occurred in 90% patients by 5th month. Of them 56% patients were treatment naive prior to LDT. LDT is thus a safe and effective therapy in hyperthyroid patients and can be recommended as a primary modality of management.

Increased Progression-Free Survival with Cabozantinib Versus Placebo in Patients with Radioiodine-Refractory Differentiated Thyroid Cancer Irrespective of Prior Vascular Endothelial Growth Factor Receptor-Targeted Therapy and Tumor Histology: A Subgroup Analysis of the COSMIC-311 Study

Background: Lenvatinib and sorafenib are standard of care first-line treatments for advanced, radioiodine-refractory (RAIR) differentiated thyroid cancer (DTC). However, most patients eventually become treatment-resistant and require additional therapies. The phase 3 COSMIC-311 study investigated cabozantinib in patients with RAIR DTC who progressed on lenvatinib, sorafenib, or both and showed that cabozantinib provided substantial clinical benefit. Presented in this study is an analysis of COSMIC-311 based on prior therapy and histology. Methods: Patients were randomized 2:1 (stratification: prior lenvatinib [yes/no]; age [≤65, >65 years]) to oral cabozantinib (60 mg tablet/day) or matched placebo. Eligible patients received 1-2 prior vascular endothelial growth factor receptor-targeting tyrosine kinase inhibitors for DTC (lenvatinib or sorafenib required), had a confirmed DTC diagnosis, and were refractory to or ineligible for radioiodine therapy. For this analysis, progression-free survival (PFS) and objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 by a blinded independent radiology committee were evaluated by prior therapy (lenvatinib only, sorafenib only, both) and histology (papillary, follicular, oncocytic, poorly differentiated). Results: Two hundred fifty-eight patients were randomized (170 cabozantinib/88 placebo) who previously received sorafenib only (n = 96), lenvatinib only (n = 102), or both (n = 60). The median follow-up was 10.1 months. The median PFS (months) with cabozantinib/placebo was 16.6/3.2 (sorafenib only: hazard ratio [HR] 0.13 [95% confidence interval, CI, 0.06-0.26]), 5.8/1.9 (lenvatinib only: HR 0.28 [95% CI 0.16-0.48]), and 7.6/1.9 (both: HR 0.27 [95% CI 0.13-0.54]). The ORR with cabozantinib/placebo was 21%/0% (sorafenib only), 4%/0% (lenvatinib only), and 8%/0% (both). Disease histology consisted of 150 papillary and 113 follicular, including 43 oncocytic and 36 poorly differentiated. The median PFS (months) with cabozantinib/placebo was 9.2/1.9 (papillary: HR 0.27 [95% CI 0.17-0.43]), 11.2/2.5 (follicular: HR 0.18 [95% CI 0.10-0.31]), 11.2/2.5 (oncocytic: HR 0.06 [95% CI 0.02-0.21]), and 7.4/1.8 (poorly differentiated: HR 0.18 [95% CI 0.08-0.43]). The ORR with cabozantinib/placebo was 15%/0% (papillary), 8%/0% (follicular), 11%/0% (oncocytic), and 9%/0% (poorly differentiated). Safety outcomes evaluated were consistent with those previously observed for the overall population. Conclusions: Results indicate that cabozantinib benefits patients with RAIR DTC, regardless of prior lenvatinib or sorafenib treatments or histology. Clinical Trial Registration Number: NCT03690388.

FAPI PET Missed Widespread Bone Marrow Metastases From Follicular Thyroid Cancer That Were Detected by FDG PET

ABSTRACT

A 62-year-old woman with follicular thyroid cancer who had received total thyroidectomy and multiple rounds of radioactive iodine therapy underwent both 18 F-FDG and 18 F-FAPI PET/CT. 18 F-FAPI PET failed to reveal widespread bone marrow metastases that were clear visualized on 18 F-FDG PET. This case highlights that FAPI PET may not be used to describe bone metastases in detail in follicular thyroid cancer patients, as it is not a sensitive method to detect bone marrow metastases.

Clinical Implications of Adding SPECT/CT to Radioiodine Whole-Body Scan in Patients With Differentiated Thyroid Cancer: A Systematic Review and Meta-analysis

PURPOSE

This study aimed to determine the usefulness of adding SPECT/CT to radioiodine whole-body scans (WBSs) for the treatment of differentiated thyroid cancer (DTC).

PATIENTS AND METHODS

A systematic review and meta-analysis were performed following the PRISMA guidelines (PROSPERO registration: CRD42022341732) to compare the feasibility of conclusive readings and the frequency of changes in treatment plans in patients with DTC undergoing WBS + SPECT/CT versus WBS. MEDLINE, EMBASE, and Cochrane databases were searched to identify relevant articles concerning thyroid cancer, radioactive iodine, and SPECT/CT or SPECT, published before August 16, 2023. Studies not comparing WBS + SPECT/CT with WBS, those lacking target outcomes, and those not involving human subjects were excluded. The risk of bias was assessed using the RoBANS 2.0 (Risk of Bias Assessment Tool for Nonrandomized Studies) tool. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system was used to evaluate the quality of evidence and strength of recommendations.

RESULTS

A total of 30 studies (prospective n = 9, retrospective n = 21) were included in the meta-analyses. Adding SPECT/CT to WBS was shown to increase conclusive readings for cervical lesions, extracervical lesions, and all regions. Lesion-based analyses showed improvements of 14%, 20%, and 18%, respectively, whereas scan-based analyses showed improvements of 27%, 9%, and 34%. The addition of SPECT/CT to WBS led to changes in 30% of treatment plans after diagnostic scans and 9% of treatment plans after posttherapeutic scans. The quality of evidence and strength of recommendations were low.

CONCLUSIONS

Compelling evidence demonstrates that the addition of SPECT/CT to WBS improves lesion localization, diagnostic performance, and therapy plan for patients with DTC.

Differentiated thyroid carcinoma: what the nonspecialists needs to know

Differentiated thyroid carcinoma (DTC) accounts for most cases of thyroid cancer, and the heterogeneity of DTC requires that management decisions be taken by a multidisciplinary team involving endocrinologists, head and neck surgeons, nuclear medicine physicians, pathologists, radiologists, radiation oncologists, and medical oncologists. It is important for nonspecialists to recognize and refer patients with DTC who will benefit from a specialized approach. Recent advances in knowledge and changes in management of DTC call for the need to raise awareness on the part of these nonspecialist physicians, including general endocrinologists and medical oncologists at large. We provide an overview of diagnostic and therapeutic principles in DTC, especially those that bear direct implication on day-to-day management of these patients by generalists. Patients with DTC may be broadly categorized as having localized, locally persistent/recurrent, or metastatic disease. Current recommendations for DTC include a three-tiered system that classifies patients with localized disease into low, intermediate, or high risk of persistent or recurrent disease. Risk stratification should be performed at baseline and repeated on an ongoing basis, depending on clinical evolution. One of the overarching goals in the management of DTC is the need to personalize treatment by tailoring its modality and intensity according to ongoing prognostic stratification, evolving knowledge about the disease, and patient characteristics and preference. In metastatic disease that is refractory to radioactive iodine, thyroid tumors are being reclassified into molecular subtypes that better reflect their biological properties and for which molecular alterations can be targeted with specific agents.

Combined clinical variable and radiomics of post-treatment total body scan for prediction of successful I-131 ablation in low-risk papillary thyroid carcinoma patients

To explore the feasibility of combined radiomics of post-treatment I-131 total body scan (TBS) and clinical parameter to predict successful ablation in low-risk papillary thyroid carcinoma (PTC) patients. Data of low-risk PTC patients who underwent total/near total thyroidectomy and I-131 ablation 30 mCi between April 2015 and July 2021 were retrospectively reviewed. The clinical factors studied included age, sex, and pre-ablative serum thyroglobulin (Tg). Radiomic features were extracted via PyRadiomics, and radiomic feature selection was performed. The predictive performance for successful ablation of the clinical parameter, radiomic, and combined models (radiomics combined with clinical parameter) was calculated using the area under the receiver operating characteristic curve (AUC). One hundred and thirty patients were included. Successful ablation was achieved in 77 patients (59.2%). The mean pre-ablative Tg in the unsuccessful group (15.50 ± 18.04 ng/ml) was statistically significantly higher than those in the successful ablation group (7.12 ± 7.15 ng/ml). The clinical parameter, radiomic, and combined models produced AUCs of 0.66, 0.77, and 0.87 in the training sets, and 0.65, 0.69, and 0.78 in the validation sets, respectively. The combined model produced a significantly higher AUC than that of the clinical parameter (p < 0.05). Radiomic analysis of the post-treatment TBS combined with pre-ablative serum Tg showed a significant improvement in the predictive performance of successful ablation in low-risk PTC patients compared to the use of clinical parameter alone.Thai Clinical Trials Registry TCTR identification number is TCTR20230816004 ( https://www.thaiclinicaltrials.org/show/TCTR20230816004 ).

Unusual onset of Graves' disease associated with thymic hyperplasia in a 5-year-old girl with congenital bilateral clinical anophthalmia: diagnostic and therapeutic challenges

OBJECTIVES

Graves' disease (GD) is a rare auto-immune disorder in pediatric population. The association between GD and thymic hyperplasia was rarely reported in children. Diagnosis and management of GD are challenging in children.

CASE PRESENTATION

This report presents the case of a 5-year-old girl with a personal history of asthma and congenital bilateral isolated clinical anophthalmia who presented with acute congestive heart failure, sinus tachycardia and atypical signs of orbitopathy with edema and erythema of the lower right eyelid and excessive tearing. The diagnosis of GD was based on detecting a suppression of serum TSH level and the presence of high titers of TRAbs. Relapse occurred after 10 months of antithyroid drugs with chief complaints of palpitations, dyspnea and dysphagia. Computed tomography showed heterogeneous anterior mediastinal mass with no invasion into the surrounding tissue. The marked shrinkage of the mass after radioiodine therapy supported the diagnosis of thymic hyperplasia associated with GD.

CONCLUSIONS

The presence of clinical anophthalmia may be a confusing factor for the diagnosis of Graves' ophthalmopathy. Recognition of the association between GD and thymic hyperplasia would avoid invasive diagnostic procedures and unnecessary surgical resection. Radioiodine therapy may be used in young children with repeated relapses of GD.

Hyperthyroidism

Thyrotoxicosis causes a variety of symptoms and adverse health outcomes. Hyperthyroidism refers to increased thyroid hormone synthesis and secretion, most commonly from Graves' disease or toxic nodular goitre, whereas thyroiditis (typically autoimmune, viral, or drug induced) causes thyrotoxicosis without hyperthyroidism. The diagnosis is based on suppressed serum concentrations of thyroid-stimulating hormone (TSH), accompanied by free thyroxine and total or free tri-iodothyronine concentrations, which are raised (overt hyperthyroidism) or within range (subclinical hyperthyroidism). The underlying cause is determined by clinical assessment, detection of TSH-receptor antibodies and, if necessary, radionuclide thyroid scintigraphy. Treatment options for hyperthyroidism include antithyroid drugs, radioactive iodine, and thyroidectomy, whereas thyroiditis is managed symptomatically or with glucocorticoid therapy. In Graves' disease, first-line treatment is a 12-18-month course of antithyroid drugs, whereas for goitre, radioactive iodine or surgery are preferred for toxic nodules or goitres. Evidence also supports long-term treatment with antithyroid drugs as an option for patients with Graves' disease and toxic nodular goitre.

An unusual evolution of thyroid function after therapeutic plasma exchange in Graves' disease with cholestatic jaundice: A case report

RATIONALE

Methimazole (MMI) is the first-line agent in the treatment of hyperthyroidism. However, rare but severe cholestatic jaundice may occur. Therapeutic plasma exchange (TPE) may provide an alternative treatment for such patients and they received thyroidectomy/radioactive iodine ablation or continued oral anti hyperthyroidism medication immediately after TPE session in the reported literatures. The case reported here is, to our knowledge, the first to describe the long interval between anti hyperthyroidism therapy and TPE in such patients.

PATIENT CONCERNS

A 49-year-old Chinese woman had developed worsening jaundice 3 weeks after receiving methimazole (20 mg/day) for the treatment of hyperthyroidism secondary to Graves' disease (GD). Additionally, she had a 2-year history of type 2 diabetes.

DIAGNOSIS

Hyperthyroidism secondary to GD, MMI-induced severe cholestatic jaundice and type 2 diabetes.

INTERVENTIONS

Methimazole was discontinued and the patient received 3 times of TPE, about 3-month glucocorticoid treatment, insulin administration accordingly and other conventional liver-protecting therapy.

OUTCOMES

Her thyroid function was stabilized with small dose of thyroxine substitution and euthyroid status persisted after thyroxine discontinuation until hyperthyroidism recurred 7 months later while her cholestatic jaundice was eventually recovered by about 3-month glucocorticoid therapy.

LESSONS

Due to the complex interplay between liver function and thyroid hormones, there may be unusual changes of thyroid function in GD patients with severe liver injury after TPE. By this case, we want to highlight the importance of a closely following up of thyroid function in order to deliver appropriate health suggestions for patients.

Analysis of dose-TSH response effect of levothyroxine soft-gel formulation

Background

Hypothyroidism is treated with daily levothyroxine (LT4). In recent years, soft gel caps of LT4 (LT4-C) have been commercialized, and their performance has been optimized. Since guidelines recommend dose LT4 according to the tablet preparation efficacy, the present study was undertaken to obtain data about the daily requirement, normalized per body weight, of LT4-C.

Methods

Patients undergoing LT4-C after total thyroidectomy and radioiodine treatment for differentiated thyroid carcinoma were selected. There was no specific indication of suppression of TSH (i.e., <0.5 or <0.1 mIU/L). Patients were required to maintain a stable LT4 dose during the study period. Patients with interfering factors were excluded from this study.

Results

Thirty patients were enrolled (18 females and 12 males; median age, 50 years; median body weight, 71 kg; median LT4-C dose, 1.71 µg/kg/day). The analysis of patient age did not reveal any differences. The LT4-C dose correlated with free-T4 p = 0.03), but not with TSH (p = 0.42) and free-T3 (p = 0.13). TSH was <1.0 mIU/L in 90% of the cases. The LT4-C dose-TSH response effect was analysed by probit regression model: the probability to achieve TSH <1.0 mIU/l was 99% with a dose of 1.84 (95%CI 1.57-2.12) µg/kg/day, 75% with a dose of 1.38 µg/kg/day (95%CI 1.17-1.59), and 50% with a dose of 1.20 (95%CI 0.96-1.43). At ROC curve analysis, the most accurate cut-off of LT4-C dose to achieve TSH <1.0 mIU/l was 1.53 ug/kg/day with 70% sensitivity and 100% specificity.

Conclusions

Athyreotic patients can be initially treated with an LT4-C dose lower than previously stated. Therefore, further prospective studies are warranted.

Outcomes of Patients With Graves Disease 25 Years After Initiating Antithyroid Drug Therapy

CONTEXT

Graves disease (GD) is a leading cause of hyperthyroidism. Detailed investigations and predictors of long-term outcomes are missing.

OBJECTIVE

This work aimed to investigate the outcomes in GD 25 years after initiating antithyroid drug treatment, including disease course, clinical and biochemical predictors of relapse, and quality of life.

METHODS

A retrospective follow-up was conducted of GD patients that participated in a randomized trial from 1997 to 2001. Demographic and clinical data were obtained from medical records and questionnaires. Biobank samples were analyzed for inflammatory biomarkers and compared with age- and sex-matched healthy individuals.

RESULTS

We included 83% (182/218) of the patients from the original study. At the end of follow-up, normal thyroid function was achieved in 34%. The remaining had either active disease (1%), spontaneous hypothyroidism (13%), or had undergone ablative treatment with radioiodine (40%) or thyroidectomy (13%). Age younger than or equal to 40 years, thyroid eye disease (TED), smoking, and elevated levels of interleukin 6 and tumor necrosis factor receptor superfamily member 9 (TNFRS9) increased the risk of relapsing disease (odds ratio 3.22; 2.26; 2.21; 1.99; 2.36). At the end of treatment, CD40 was lower in patients who maintained normal thyroid function (P = .04). At the end of follow-up, 47% had one or more autoimmune diseases, including vitamin B12 deficiency (26%) and rheumatoid arthritis (5%). GD patients who developed hypothyroidism had reduced quality of life.

CONCLUSION

Careful lifelong monitoring is indicated to detect recurrence, hypothyroidism, and other autoimmune diseases. Long-term ATD treatment emerges as a beneficial first-line treatment option, especially in patients with young age at onset or presence of TED.

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.

Absorbed dose coefficients for pediatric differentiated thyroid cancer patients undergoing radioiodine therapy

The escalating incidence of differentiated thyroid cancer (DTC) in pediatric patients and the resultant growing use of radioactive iodine (RAI) reinforce the need to evaluate radiation exposure to normal tissues and radiation-induced health risks in pediatric patients undergoing RAI therapy. In the current study, we calculated absorbed dose coefficients (i.e. absorbed dose per unit activity administered, mGy MBq-1) specific for pediatric patients with localized DTC undergoing RAI therapy following total thyroidectomy for use in epidemiological studies. We first modified previously-published biokinetic models for adult thyroid cancer patients to achieve a reasonable agreement with iodine biokinetics observed in pediatric patients or design principles addressed in the International Commission on Radiological Protection (ICRP) reference age-specific biokinetic models. We then combined the biokinetic models in conjunction withSvalues derived from ICRP reference pediatric voxel phantoms. The absorbed dose coefficients for pediatric patients were overall greater than those for adults with a ratio (pediatric/adult) up to 11.6 and rapidly decreased with increasing age. The sensitivity analysis showed that the renal clearance rate andSvalues may have the greatest impact on the absorbed dose coefficients with the rank correlation coefficients ranging from -0.53 to -0.82 (negative correlations) and from 0.51 to 0.80 (positive correlations), respectively. The results of the current study may be utilized in clinical or epidemiological studies to estimate organ-specific radiation absorbed doses and radiation-associated health risks among pediatric thyroid cancer patients.

The value of the first postoperative diagnostic I-131 scan in patients with papillary thyroid carcinoma

OBJECTIVE

To explore the feasibility of the postoperative diagnostic 131I whole-body planar scans (Dx-WBS) in papillary thyroid cancer (PTC) patients, and to clarify its value for accurate staging, risk stratification, and postoperative radioactive iodine (RAI) treatment management.

DESIGN

Retrospective study from 2015 to 2021.

SETTING

A total of 1294 PTC patients in the tertiary referral hospital.

PARTICIPANTS

Patients with differentiated thyroid cancer who underwent total/subtotal thyroidectomy were included. Patients with non-PTC pathological type, non-first RAI treatment, and incomplete data such as Dx-WBS and postablation WBS (Rx-WBS) were excluded.

METHODS

The diagnostic efficacy of Dx-WBS was calculated with Rx-WBS as the reference. All patients were initially staged by the 8th edition of TNM staging, and risk stratification was performed based on clinical and pathological information. After Dx-WBS, the risk stratification was re-evaluated, and management was reconfirmed.

RESULTS

The detection rates of Dx-WBS for residual thyroid, cervical lymph nodes, upper mediastinal lymph nodes, lung, and bone distant metastasis were 97.6%, 78.3%, 82.1%, 66.7%, and 61.2%, respectively. The risk stratification of 113 patients (8.7%) changed after Dx-WBS, of which 107 patients changed from low to intermediate risk, 2 from low to high risk, and 4 from medium to high risk. A total of 241 patients (18.6%) adjusted the RAI regimen after Dx-WBS.

CONCLUSION

This study confirms the diagnostic efficacy of the postoperative Dx-WBS in PTC patients and the value of Dx-WBS in accurately assessing risk stratification, as well as assisting in determining RAI treatment.