Comparison of 1.1 GBq and 2.2 GBq Activities in Patients with Low-Risk Differentiated Thyroid Cancer Requiring Postoperative 131I Administration: A Real Life Study

OBJECTIVES

To compare the efficacy of low and moderate ¹³¹I activities in low-risk differentiated thyroid carcinoma (DTC) patients requiring postoperative thyroid remnant ablation in a real-world clinical setting.

METHODS

We retrospectively reviewed the records of 299 low-risk DTC patients (pT1-T2, Nx(0) Mx) who had undergone (near)-total thyroidectomy followed by ¹³¹I therapy, using either low (1.1 GBq) or moderate (2.2 GBq) radioiodine activities. The response to initial treatments was evaluated after 8-12 months, and patient responses were classified according to the 2015 American Thyroid Association guidelines.

RESULTS

An excellent response was observed in 274/299 (91.6%) patients, specifically, in 119/139 (85.6%) and 155/160 (96.9%) patients treated with low and moderate ¹³¹I activities, respectively (p = 0.029). A biochemically indeterminate or incomplete response was observed in seventeen (22.2%) patients treated with low ¹³¹I activities and three (1.8%) patients treated with moderate ¹³¹I activities (p = 0.001). Finally, five patients showed an incomplete structural response, among which three and two received low and moderate ¹³¹I activities, respectively (p = 0.654).

CONCLUSIONS

When ¹³¹I ablation is indicated, we encourage the use of moderate instead of low activities, in order to reach an excellent response in a significantly larger proportion of patients, including patients with the unexpected persistence of the disease.

Recombinant human thyrotropin versus thyroid hormone withdrawal preparation for radioiodine ablation in differentiated thyroid cancer: Experience in a South Taiwanese medical center

This retrospective study was designed to compare the treatment response of patients with differentiated thyroid cancer (DTC) prepared for radioiodine ablation (RIA) with thyroid hormone withdrawal (THW) or recombinant human thyrotropin (rhTSH) stimulation. Patients with DTC were followed-up retrospectively between 2013 and 2018 in Kaohsiung Chang Gung Memorial Hospital, Taiwan. We compared the excellent response ratios between THW (49.9%) and rhTSH (50.1%) stimulation. Patients were then divided into subgroups, on the basis of age, sex, extrathyroidal extension, lymph node metastasis, and tumor-node-metastasis stage, for analysis. In all, 647 patients were followed-up after RIA. The ratios of THW or rhTSH use in the different subgroups were not statistically significant. In all the patients, the excellent response rate with THW and rhTSH was 80% and 76.5%, respectively, which was not statistically significant. The subgroup analysis, including age, sex, extrathyroidal extension, lymph node metastasis, and tumor-node-metastasis stage (low and high risk), showed similar results. Furthermore, the logistic regression analysis revealed no statistically significant differences among the subgroups. The multivariate analysis showed extrathyroidal extension, lymph node metastasis, and high I¹³¹ dose were the prognostic factors affecting the excellent response rate. In conclusion, the THW and rhTSH preparations for RIA were similar in terms of the excellent response rates and subgroup clinical outcomes.

Outcomes after radioiodine ablation in patients with thyroid cancer: Long-term follow-up of a Chinese randomized clinicaltrial

OBJECTIVE

Two large randomized trials of patients with differentiated thyroid cancer (DTC) reported recently (HiLo and ESTIMABL1) found that the recurrence rate among patients who underwent 1.1 GBq radioactive iodine (RAI) ablation was not higher than that of patients who underwent 3.7 GBq radioactive iodine (RAI) ablation. However, no similar studies have been conducted in China. We aimed to report clinical outcomes in Chinese patients with low/intermediate risk of recurrence DTC after long-term follow-up, and evaluate the risk factors that influence the presence or absence of incomplete response at the final follow-up.

DESIGN

A long-term follow-up of a Chinese randomized clinical trial (October 2014 and February 2021) was conducted.

PATIENTS

A total of 506 DTC patients at low/intermediate risk of recurrence who were randomized into two groups to receive 1.1 (n = 251) or 3.7 GBq (n = 255) RAI ablation following thyroid hormone withdrawal were followed on levothyroxine treatment for a median of 4.5 years (range: 1.6-6.3).

MEASUREMENTS

Suppressed serum thyroglobulin (Tg) and anti-thyroglobulin antibody (TgAb) levels were determined, and neck ultrasonography was performed.

RESULTS

At the final follow-up, 499 (98.6%) patients showed an excellent response. The other seven patients (two patients underwent 1.1 GBq and five patients underwent 3.7 GBq RAI ablation, respectively) showed either structural incomplete response (lymph node metastasis, n = 1), biochemical incomplete response (increased serum Tg ≥ 1 ng/ml, or increased positive TgAb levels, n = 5), or indeterminate response (stable positive TgAb levels, n = 1). The risk of incomplete response at the final follow-up was significantly increased in patients with stimulated serum Tg ≥ 10 ng/ml at ablation (p = .003) and in patients with unsuccessful ablation (p = .008).

CONCLUSION

Our findings indicated that there was no difference in the long-term outcomes with RAI ablation using either 1.1 or 3.7 GBq in patients with low/intermediate risk of recurrence DTC, and 1.1 GBq RAI might be suitable for patients who are recommended for ablation.

Clinical predictors of I-131 therapy failure in differentiated thyroid cancer by machine learning: A single-center experience

Well-differentiated thyroid carcinoma is predominantly a slow-growing malignancy, amendable to treatment, and has an excellent prognosis following thyroidectomy and radioiodine (RAI) therapy. However, patients who fail the initial RAI treatment attempt may require repeated RAI or other treatments and with this, comes an associated impact on patient quality of life. Therefore, the anticipation of patients in whom there is a higher risk of RAI failure may help in patient risk stratification and subsequent management. We conducted a retrospective review to determine the factors associated with initial RAI therapy failure in well-differentiated thyroid cancer patients. Using scikit-learn from Python, we implemented a machine-learning algorithm to determine the clinical patient factors associated with a higher likelihood of treatment resistance. We found that clinical factors such as tumor focality (P = 0.026) and lymph node invasion at surgical resection (P = 0.0135) were significantly associated with initial treatment failure following RAI. Elevated serum thyroglobulin (Tg) and Tg antibody levels following surgery but before RAI were also associated with treatment resistance (P < 0.0001 and P = 0.011 respectively). Less expected factors such as decreased time from surgery to RAI were also associated with treatment failure, however not to a statistically significant degree (P > 0.064). Clinical outcomes following RAI can be stratified by identifying factors that are associated with initial treatment failure. These findings can help restratify patients for RAI treatment and change patient management in certain cases. Such stratification will ultimately help to optimize successful treatment outcomes and improve patient quality of life.

Treatment Modality and Risk of Heart Failure in Patients With Long-Standing Graves' Disease: A Nationwide Population-Based Cohort Study

Background

Optimal treatment for persistent Graves' disease following 12-18 months of treatment with anti-thyroid drugs (ATDs) is unclear. Given the increased risk of cardiovascular morbidity and mortality with hyperthyroidism, assessing the risk of cardiovascular events associated with different treatment modalities after the conventional ATD course would be valuable in determining the appropriate next-line therapy.

Methods

This retrospective cohort study included data from the Korean National Health Insurance database of 16,882 patients with newly diagnosed hyperthyroidism who received primary ATD treatment for 24 months. Patients were categorized based on the treatment they received after receiving ATD for 24 months: continued ATD for at least 12 more months (ATD group), radioiodine ablation (RIA) with remission (RIA group 1), and RIA without remission (RIA group 2). The incidence and risk of heart failure (HF), the leading cause of cardiovascular mortality in hyperthyroidism, were compared between patients and age-and sex-matched controls.

Results

There were 16,516 (97.8%) patients in the ATD group, 230 (1.4%) in RIA group 1, and 136 (0.8%) in RIA group 2. Compared to that of controls, a significant difference in the cumulative incidence of HF was observed according to second-line treatment modality after adjusting for covariates; the risk was highest in patients in RIA group 2, with a hazard ratio (HR) of 2.54 (95% confidence interval (CI) 1.60-4.03), followed by those in the ATD group, with an HR of 1.23 (95% CI 1.20-1.36). Patients in RIA group 1 were not at an increased risk of HF compared to their matched controls (HR 0.77; 95% CI 0.38-1.54). When patients in the ATD group were further classified by the duration of ATD treatment at one-year intervals, the risk of HF was higher in patients with longer ATD use (p for linear trend < 0.001).

Conclusions

In patients with long-standing hyperthyroidism treated with conventional duration of ATD therapy, the risk of HF was attenuated by RIA with remission of hyperthyroidism and increased as ATD was required for longer duration. To reduce the risk of HF, resolution of hyperthyroidism with RIA should be considered in patients with long-standing Graves' disease.

Post-Surgical Ablative or Adjuvant Radioiodine Therapy Has No Impact on Outcome in 1-4 cm Differentiated Thyroid Cancers without Extrathyroidal Extension

Whether to conduct remnant ablation or adjuvant radioactive iodine (RAI) therapy in patients with intrathyroidal differentiated thyroid carcinoma (DTC), sized 1.1-4 cm, is debated. We evaluated the impact of RAI on outcome in this category of DTCs. We retrospectively enrolled 308 patients submitted to total thyroidectomy: 198 had tumors sized 1.1-2 cm (Group 1) and 110 of 2.1-4 cm (Group 2). Both groups were divided into patients receiving and not receiving RAI after surgery. RAI+ and RAI- patients did not significantly differ, regarding several clinical and pathological features. Final outcome was defined according to dynamic risk stratification. Remission was observed in the majority of Group 1 and Group 2 patients and outcome did not significantly differ between RAI+ and RAI- patients: respectively, 95.8% vs. 93.7% in Group 1, and 87.7% vs. 86.5% in Group 2. The majority of persistent cases, either RAI+ or RAI-, received therapeutic RAI administration, and about 50% of RAI- cases had an excellent response at final follow up, whereas no RAI+ persistent patients had a beneficial effect. Our findings demonstrate that patients with an intrathyroidal DTC sized 1.1-4 cm do not benefit from RAI. The outcome of these patients remains favorable, and the few patients with persistent diseases can be treated with RAI during follow up.

Cytokines: Application in recurrence appraisal for differentiated thyroid carcinoma and their relation with radioiodine ablation

The limitations in discriminating preablation disease-active status of differentiated thyroid carcinoma (DTC) still represent a major challenge to radioiodine dose management. Cytokines, the small protein signaling molecules that constitute the thyroid tumor microenvironment, play significant roles in the facilitation of intercellular communication and the control of tumorigenesis. Also, more attention should be paid to the molecular events within the innate and adaptive immune systems that occur after the organism being exposed to ionizing radiation. Therefore, we implemented a study of 260 patients with DTC in thyroid hormone withdrawal status who were treated with total thyroidectomy to explore the relationship between cytokines and recurrence/active disease status. Besides, we made a cross-sectional study to analyze pre- and post-ablation serum concentration of cytokines of 86 patients with DTC. There was a relationship between clinicohistopathological characteristics of patients with DTC and the presence of cytokines. It is noteworthy that patients with recurrence/active disease were at a higher serum interleukin-2 receptor (IL-2R) level than the disease-free patients (213.59 ± 75.43 pg/ml vs. 186.80 ± 77.40 pg/ml, P = 0.005). Positive correlation was observed between serum IL-2R and thyroglobulin (Tg) (P = 0.003). We also found significant changes in the cytokine profile after radioiodine ablation, including the decrease of tumor necrosis factor-α and IL-8 (P < 0.001, P < 0.001, respectively), and increase of IL-2R (P < 0.001). Thus, we suggest that serum IL-2R may assist in evaluating the disease status during the post-thyroidectomy follow-up and radioiodine therapy has an immunoregulatory effect on serum cytokines.

Radioiodine in Differentiated Thyroid Carcinoma: Do We Need Diagnostic Pre-Ablation Iodine-123 Scintigraphy to Optimize Treatment?

Changing insights regarding radioiodine (I-131) administration in differentiated thyroid carcinoma (DTC) stir up discussions on the utility of pre-ablation diagnostic scintigraphy (DxWBS). Our retrospective study qualitatively and semi-quantitatively assessed posttherapy I-131 whole-body scintigraphy (TxWBS) data for thyroid remnant size and metastasis. Findings were associated with initial treatment success after nine months, as well as clinical, histopathological, and surgical parameters. Possible management changes were addressed. A thyroid remnant was reported in 89 of 97 (92%) patients, suspicion of lymph node metastasis in 26 (27%) and distant metastasis in 6 (6%). Surgery with oncological intent and surgery by two dedicated thyroid surgeons were independently associated with a smaller remnant. Surgery at a community hospital, aggressive tumor histopathology, histopathological lymph node metastasis (pN1) and suspicion of new lymph node metastasis on TxWBS were independently associated with an unsuccessful treatment. Thyroid remnant size was unrelated to treatment success. All 13 pN1 patients with suspected in situ lymph node metastases on TxWBS had an unsuccessful treatment, opposite 19/31 (61%) pN1 patients without (p = 0.009). Pre-ablative knowledge of these TxWBS findings had likely influenced management in 48 (50%) patients. Additional pre-ablative diagnostics could optimize patient-tailored I-131 administration. DxWBS should be considered, especially in patients with pN1 stage or suspected in situ lymph node metastasis. Dependent on local surgical expertise, DxWBS is not recommended to evaluate thyroid remnant size.

Ventricular Fibrillation: Potential Deadly Consequence of Discontinuation of Methimazole Prior to Radioiodine Ablation

The following case involves a 62-year-old female patient suffering from heart failure with reduced ejection fraction (HFrEF) secondary to non-ischemic cardiomyopathy and Graves disease, who developed ventricular fibrillation (VF) after discontinuation of methimazole in preparation for radioiodine ablation. Electrocardiogram (ECG) showed a severely prolonged QTc in the setting of thyrotoxicosis, which significantly improved with high dose methimazole. VF secondary to thyrotoxicosis has rarely been reported and the literature review shows scarce data on its mechanism. Our case demonstrates not only a possible mechanism for the arrhythmia, but also highlights a potential risk factor for it. The report details how discontinuing antithyroid medication leads to VF in our patient and reviews the current literature on antithyroid withdrawal prior to radioiodine ablation therapy. Caution should be taken when discontinuing antithyroid medications in patients with advanced heart failure as potentially lethal ventricular arrhythmias can ensue.

Radioactive iodine therapy for pediatric Graves' disease: a single-center experience over a 10-year period

Introduction Only about 30% of pediatric patients with Graves' hyperthyroidism achieve remission with medical therapy, and therefore radioactive iodine (RAI) therapy is often used as a definitive treatment. Although the goal of RAI is permanent hypothyroidism, this is not consistently achieved. We conducted a chart review to determine the factors associated with the success of RAI. We also tried to determine optimal follow-up post RAI and if there was an optimal L-thyroxine dose that would normalize the hypothyroid state quickly. Methods This is a retrospective chart review of Graves' patients who underwent RAI between 2008 and 2017. We included age, sex, time from diagnosis, thyroid gland size, total dose of I-131 and dose in μCi/g of thyroid tissue. Patients were grouped based on outcome and analyzed using univariate and multivariate logistic regression. Follow-up thyroid levels post RAI and after starting l-thyroxine were analyzed. Results There were 78 ablations including six repeat ablations. Seventy-three percent became hypothyroid, 23% remained overtly or subclinically hyperthyroid, and 4% were euthyroid. Smaller thyroid size (36.5 vs. 47.4 g; p = 0.037) and higher dose of I-131 (242 vs. 212 μCi/g thyroid tissue; p = 0.013) were associated with a higher likelihood of hypothyroidism. Most patients remained hyperthyroid at 1 month post RAI, but by 3 months the majority became hypothyroid. There was no clear L-thyroxine dose that normalized hypothyroidism quickly. Conclusions An I-131 dose close to 250 μCi/g of thyroid tissue has a higher likelihood of achieving hypothyroidism. Testing at 2-3 months after RAI is most helpful to confirm response to RAI.

In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation

OBJECTIVE

Our objective was to evaluate the trend of antithyroglobulin antibodies (TgAb) during follow-up of patients with differentiated thyroid cancer (DTC) treated without RAI, as well as their role in the risk of recurrence.

SUBJECTS AND METHODS

This was a prospective, descriptive study. A total of 152 consecutive patients with DTC treated in a single institution undergoing total thyroidectomy without RAI and followed for a median of 2.3 years (0.5-10.3) were divided in two groups: TgAb(-) (n = 111) and TgAb(+) (n = 41). Patients were classified according to AJCC 7th and 8th editions, as well as to their risk of recurrence and response to treatment categories.

RESULTS

Both groups, TgAb(-) and TgAb(+), were similar regarding patient and tumor characteristics. At the end of follow-up, 90 (59.2%), 57 (37.5%), 3 (2%) and 2 (1.3%) patients achieved excellent, indeterminate, biochemically incomplete and structurally incomplete response, respectively. The risk of structural recurrence was similar in both groups (TgAb[-] 0.9% vs. TgAb[+] 2.4%, p = 0.46). In the TgAb(+) group, TgAb became negative in 10 (24.4%), decreased ≥ 50% without negativization in 25 (60.9%), decreased < 50% in 4 (9.8%) and remained stable or increased in 2 (4.9%) cases. The only incomplete structural response had increasing TgAb during follow-up.

CONCLUSIONS

In properly selected patients with DTC, TgAb concentration immediately after total thyroidectomy should not mandate RAI ablation, and their trend during follow-up may impact the risk of recurrence.

Occipital Condyle Syndrome Caused by Isolated Bone Metastases from Thyroid Cancer

Occipital condyle syndrome is a rare cause of pain in the head which is characterized by severe and persistent unilateral suboccipital headache with unilateral hypoglossal nerve palsy. We report an elderly female who presented with dysarthria and suboccipital headache. On further evaluation, she was found to have a solitary bone metastases from thyroid cancer. She was treated with local radiation therapy for pain relief, total thyroidectomy, and high-dose radioiodine therapy. The patient is presently free of pain with very good control of the thyroid cancer status.

Changing Trend of Thyroglobulin Antibodies in Patients With Differentiated Thyroid Cancer Treated With Total Thyroidectomy Without 131I Ablation

BACKGROUND

Thyroglobulin (Tg) antibodies (TgAb) can interfere with Tg measurement and can be used as "Tg surrogate" in patients with differentiated thyroid cancer (DTC) treated with total thyroidectomy (TTx) and radioiodine remnant ablation (RRA). In contrast, few data, and in patients usually followed for a short-term follow-up, have been reported about the changes of TgAb levels in patients treated with TTx but without RRA. The aims of this study were to evaluate the changes of TgAb levels in DTC patients treated with TTx but not RRA and to identify the factors that influence these changes.

METHODS

The change in TgAb levels in 107 DTC (<1 cm) patients submitted to TTx but not RRA was evaluated. Patients were followed for a median of 6.3 years, and all had at least three determinations of TgAb and neck ultrasound (nUS).

RESULTS

TgAb levels showed a progressive decrease during follow-up. Initial TgAb levels and degree of lymphocytic infiltration influenced the time but not the rate of TgAb disappearance. No influence on time and rate of the decrease in TgAb was observed when the association with thyroperoxidase antibodies (TPOAb) levels were considered. A TgAb cutoff value of 61.9 IU/mL at first postoperative evaluation was a good indicator for disappearance of the TgAb within six years. No tumor recurrence was observed in the series. In one case, the progressive increase in TgAb anticipated the reappearance of benign thyroid tissue with lymphocytic infiltration.

CONCLUSIONS

TgAb levels decline in the majority of DTC patients treated with TTx but not ablated with radioiodine. The levels decrease rapidly after the surgical treatment and continue to decrease over time. The time of disappearance is influenced by the initial TgAb levels and the degree of lymphocytic infiltration. No influence of the actual TPOAb levels has been observed. An increase in TgAb levels should not be overlooked, since it can indicate the presence or reappearance of either normal thyroid tissue or tumor recurrence.

BEHAVIOUR OF EARLY THYROGLOBULIN AFTER TOTAL THYROIDECTOMY FOR DIFFERENTIATED THYROID CANCER

Context

The objectives of treatment of thyroid carcinoma include hormonal suppression, radioiodine ablation and follow-up with serum thyroglobulin (Tg). Tg levels should not be measured before six weeks post-thyroidectomy.

Objective

To describe the behaviour of early postoperative Tg in patients who underwent total thyroidectomy and its ability to predict the serum Tg levels after suppression.

Design

This is a retrospective cohort study.

Subjects and methods

Adult patients who underwent total thyroidectomy with at least two postoperative measurements of serum Tg, negative TgAb and concomitant serum TSH values were included. Tg, TgAb and TSH level measurements were completed two weeks postoperatively and during the follow-up period.

Results

Twenty-nine patients fulfilled all criteria. The median serum Tg level at two weeks after surgery was 3.8 ug/L (0.3 -300) with a serum TSH level of 69.9 mU/L; 11-227. At the two-week measurement, 16 (55%) patients had serum Tg levels lower than 5 ug/L and 4 patients had levels between 5-10 µg/L.

Conclusions

Postoperative early serum Tg could be an alternative to values measured six months after surgery and could be used as a predictive tool to make earlier therapeutic decisions.

[Procedure guidelines for radioiodine therapy of differentiated thyroid cancer. Version 4]

The procedure guideline for radioiodine therapy of differentiated thyroid cancer (version 4) was developed in the consensus of a representative expert group. This fulfils the level S1 (first step) within the AWMF classification of Clinical Practice Guidelines (AWMF, Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, Germany). This procedure guideline completed the guideline for surgical management of thyroid cancer (level S2) with the aspects from nuclear medicine. Controversies over ablative radioiodine therapy in small papillary thyroid cancers and in minimally invasive follicular cancer without angioinvasion, over empirical standard doses for ablative radioiodine therapy, and over the kind of TSH-stimulation were described and the guideline formulated a corridor of good clinical practice. The text has included the recent results from the National Cancer database and the SEER database (both from the USA), indicating that the ablative radioiodine therapy has improved the survival rate even in low risk patients. Such a statistically significant benefit can be detected only by a national cancer registry with long-term follow-up data.

Radioiodine therapy in patients with Graves' disease and the effects of prior carbimazole therapy

The use of radioiodine as the first line of treatment in Graves' disease is restricted in India because of its limited availability and an unrealistic risk perception associated with it. Additionally, the effectiveness of radioiodine ablation in Graves' disease is influenced by many factors. Prior medical antithyroid therapy is one such important factor.

AIMS

To analyze the efficacy of low dose radioiodine therapy (5 mCi) in treatment of naive patients of Graves' disease in comparison to that in which it was already primed with an antithyroid drug, carbimazole.

SETTINGS AND DESIGN

A non-randomized, interventional study conducted in the Department of Medicine and Endocrinology of a tertiary care institute in South India.

MATERIALS AND METHODS

The study had two groups; Group A (36 treatment naive, uncomplicated Graves' disease patients) and B (34 Graves' disease patients on carbimazole prior to radioiodine therapy). Both groups had baseline clinical, biochemical evaluation and were reassessed at 3 and 6 months for evaluating the clinical status for possible documentation of cure.

RESULTS

The cure rate was 61.1% in drug naive group and 58.8% in pretreated group at 6 months following radioiodine (P = 0.845). Higher baseline 999m technicium (99m Tc) uptake, male gender, BMI and higher baseline free thyroxine (fT4) level predicted treatment failure following radioiodine therapy.

CONCLUSIONS

Administration of carbimazole prior to low dose radioiodine therapy does not alter the efficacy of radioiodine. Low fixed dose (5 mCi) of radioactive iodine may be a safe and effective primary therapeutic option in Graves' disease patients pretreated with antithyroid drugs.

Nodular goiter with multiple cystic and solid swellings

Thyroid nodules are very common in the general population, but only 5% are malignant. We report the case of a man presenting with nodular goiter, and multiple swellings over the scalp and arm, with pathological fractures. On evaluation by fine needle aspiration, these swellings were found to be metastases from follicular thyroid carcinoma. The patient underwent total thyroidectomy, radioiodine ablation, resection of the bone lesion, and L-thyroxine suppressive therapy, with no recurrence / metastasis over a five-year follow-up.