Thyroid lobe ablation with iodine-131 in patients with differentiated thyroid carcinoma: a randomized comparison between 1.1 and 3.7 GBq activities

Diagnosis and Treatment of Acute Pleural Effusion following Radioiodine Remnant Ablation Post Lobectomy for Thyroid Cancer

Radioiodine remnant ablation (RRA) was previously demonstrated to be a safe and effective alternative to completion thyroidectomy for patients with differentiated thyroid cancer (DTC). However, its side effects have not been fully investigated, particularly in patients with lobectomy. We reported a young euthyroidal female who underwent RRA post lobectomy and lymph node dissection for papillary thyroid cancer, whose post-ablation ¹³¹I-whole-body scan accidentally showed diffuse radioiodine distribution on chest-mimicking pulmonary metastases. Immediately-added single-photon emission computed tomography/computed tomography (SPECT/CT), nevertheless, revealed a ¹³¹I-accumulating swollen left thyroid lobe and emerging pleural effusion, which relieved after short-term treatment with prednisone. In summary, acute pleural effusion ascribed to RRA-induced thoracic duct compression was reported for the first time. ¹³¹I-lobectomy-induced pleural effusion could be precisely diagnosed by SPECT/CT and efficiently manipulated via treating radiation thyroiditis with the short-term administration of corticosteroid.

Propensity Score Matched Outcome Analysis of Lobar Ablation Versus Completion Thyroidectomy in Low-Risk Differentiated Thyroid Cancer Patients: Median Follow-Up of 11 Years

Background: Radioactive iodine lobar ablation (RAILA) of the contralateral thyroid lobe has been suggested as an alternative to completion thyroidectomy in patients of differentiated thyroid cancer (DTC) who underwent initial hemithyroidectomy. However, data on long-term outcomes are scarce. In this study, we intended to describe the long-term outcomes of RAILA versus completion thyroidectomy in a cohort of low-risk DTC patients. Methods: Data of patients with low-risk DTC who underwent initial hemithyroidectomy, and were subsequently treated with either completion thyroidectomy or RAILA between 1996 and 2015, were collected and analyzed. The treatment outcomes included ablation rate, recurrence rate, recurrence-free survival (RFS), and adverse events, and were validated by propensity score matching analysis. Results: Of the 1243 patients (median age: 34 years, range: 5-78) with low-risk DTC, 514 patients underwent upfront RAILA while 729 patients underwent completion thyroidectomy followed by remnant ablation. The ablation rate following the first radioactive iodine (¹³¹I) cycle was 75.3% [95% confidence interval (CI) 71.3-78.9] in the RAILA group versus 84.1% [CI 81.2-86.6] in the completion thyroidectomy group (p < 0.001). Over median follow-up of 11.4 years (interquartile range: 8.3-15.8), the recurrence rates between the two groups were not significantly different (1.6% [CI 0.7-3.2] vs. 1.0% [CI 0.4-2.1], respectively, p = 0.343). The product limit estimate of RFS at 10 years was 98.6% [CI 97.6-99.6%] in the RAILA group versus 99.1% [CI 98.3-99.9%] in the completion thyroidectomy group (p = 0.391). The outcomes in 497 matched pairs generated through propensity score analysis were similar. None of the patients in the RAILA group experienced permanent hypocalcemia or recurrent laryngeal nerve palsy, while the corresponding rates in the completion thyroidectomy group were 10/729 (1.4%) (p = 0.006) and 5/729 (0.7%) (p = 0.080), respectively. Radiation thyroiditis was seen in 25/514 (4.9%) patients in the RAILA group versus 3/729 (0.4%) in the completion thyroidectomy group (p < 0.001). Conclusions: Upfront RAILA is seen to be a noninvasive, safe, and effective alternative to surgical completion thyroidectomy in low-risk DTC patients in the absence of macroscopic malignancy in the remaining thyroid lobe.

Radioiodine Ablation of Remaining Thyroid Lobe in Patients with Differentiated Thyroid Cancer Treated by Lobectomy: A Systematic Review and Metaanalysis

We aimed to conduct a systematic review and metaanalysis of studies reporting the performance of radioactive iodine (¹³¹I) therapy in differentiated thyroid cancer (DTC) patients requiring a completion treatment after lobectomy. We also evaluated the response to ¹³¹I therapy according to 2015 American Thyroid Association guidelines and the adverse events. Methods: A specific search strategy was designed to find articles evaluating the use of ¹³¹I in patients with evidence of DTC after lobectomy. PubMed, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science were searched. The search was updated until January 2020, without language restriction. Data were cross-checked and any discrepancy discussed. A proportion metaanalysis (with 95% confidence interval) was performed using the random-effects model. Metaregressions on ¹³¹I success were attempted. Results: The pooled success ablation rate was 69%, with better results in patients receiving a single administration of about 3.7 GBq; high heterogeneity was found (I² test, 85%), and publication bias was absent (Egger test, P = 0.57). Incomplete structural responses were recorded in only 14 of 695 (2%) patients enrolled in our analysis. Incomplete biochemical responses were observed in 8%-24% of patients, with higher rates (24%) in patients receiving low radioiodine activities (∼1.1 GBq) and lower rates (8%-18%) in patients receiving higher activities of radioiodine (∼3.7 GBq). Neck pain due to thyroiditis was reported in up to 18% of patients, but in most cases, symptoms resolved after oral paracetamol or a short course of prednisone. Conclusion: Lobar ablation with ¹³¹I is effective, especially when high ¹³¹I activities are used. However, the rate of incomplete biochemical response to initial treatment appears to be slightly higher than in the classic scheme of initial treatment of DTC. Radioisotopic lobectomy should be considered for patients with low- to intermediate-risk DTC requiring completion treatment after lobectomy due to specific individual risk factors or patient preferences.

Radioiodine Uptake and Thyroglobulin-Guided Radioiodine Remnant Ablation in Patients with Differentiated Thyroid Cancer: A Prospective, Randomized, Open-Label, Controlled Trial

BACKGROUND

Radioiodine (¹³¹I) remnant ablation (RRA) has become a key step in the postoperative treatment of differentiated thyroid cancer (DTC). However, inadequate or excessive ¹³¹I is common using fixed activities. This study was designed to explore the feasibility of radioiodine uptake and thyroglobulin (RAIU-Tg)-guided RRA.

METHODS

A total of 277 patients were randomized to the RAIU-Tg-based activity group or a fixed activity of 3.7 GBq group at a ratio of 4:1. The RAIU-Tg-based activity was established based on four levels of RAIU (≤2%, 2-5%, 5-15%, and >15%) and Tg levels (≤2, 2-5, 5-10, and >10 ng/mL). Based on this, ¹³¹I activities of 1.1, 1.85, 3.7, and 5.55 GBq were administered. If the levels for RAIU and Tg were not in the same category, the higher activity determined by either RAIU or Tg was administered. Successful RRA was defined as negative diagnostic whole-body scan and Tg <1 ng/mL (anti-Tg antibody negative) or negative diagnostic whole-body scan (anti-Tg antibody positive) under thyrotropin stimulation six months or more post RRA.

RESULTS

There was no statistically significant difference in baseline characteristics between the RAIU-Tg-based activity group (n = 207) and the fixed activity group (n = 58). The activity of ¹³¹I used in the RAIU-Tg-based activity group (3.26 ± 1.54 GBq) was significantly lower than that used in the fixed activity group (p < 0.0001), whereas the rate of successful RRA in the RAIU-Tg-based activity group was significantly higher than the rate in the fixed activity group (94.2% vs. 70.7%; p < 0.0001). The rates of successful RRA in the four subgroups of the RAIU-Tg-based activity group were comparable (p = 0.543). Although there was no statistically significant difference in the incidence of total/short-term adverse effects between the RAIU-Tg-based activity group and the fixed activity group, a significantly lower incidence of intermediate adverse effects, which predominantly consisted of xerostomia, was reported in the RAIU-Tg-based activity group.

CONCLUSIONS

Compared to a fixed activity of 3.7 GBq, RAIU-Tg-guided dosimetry can improve the success rate and decrease the incidence of intermediate side effects of RRA in postoperative patients with DTC.

Comparison of treatment efficacy 1 and 2 years after thyroid remnant ablation with 1110 versus 5550 MBq of iodine-131 in patients with intermediate-risk differentiated thyroid cancer

BACKGROUND

Radioiodine ablation may be associated with improved survival in patients with intermediate-risk follicular cell differentiated thyroid cancer (FCDTC). The aim of this study was to compare ablation efficacy of 1110 versus 5500 MBq of iodine-131 (I) in FCDTC patients with intermediate risk.

METHODS

Thirty-nine patients with intermediate-risk FCDTC (T3N0, T1-2N1b and T1-3N1a) were treated with 1110 MBq of I and compared with 43 age-matched and sex-matched patients who received 5550 MBq of I. Patients with invasive histology, extensive lymph node involvement, and preablation thyroglobulin (Tg) of more than 100 ng/ml were excluded from the study. All patients underwent total or near total thyroidectomy with or without lymph node dissection. Response to treatment was evaluated 1 and 2 years after I treatment.

RESULTS

We studied four male and 78 female patients, age range 21-69 years. Preablation Tg level was 12.7±17.8 and 15.8±22.6 ng/ml in patients in the low-dose and high-dose groups, respectively (P=0.48). Anti-Tg antibody level as well as T and N staging were not significantly different in the two groups (P>0.2). One and 2 years after treatment, an excellent response was noted in 19 and 22 patients in the low-dose group and in 16 and 23 patients in the high-dose group, respectively (P>0.3). Using logistic regression analysis, preablation Tg was the only significant factor in the prediction of an incomplete response 2 years after therapy.

CONCLUSION

1110 MBq of I was as effective as 5550 MBq of I in the treatment of FCDTC patients with intermediate risk 1 and 2 years after therapy.

I-131 for Remnant Ablation in Differentiated Thyroid Cancer After Thyroidectomy: A Meta-Analysis of Randomized Controlled Evidence

Background

The aim of this study was to compare the success rate of various levels of I-131 activity for use in remnant ablation in low-risk differentiated thyroid cancer.

Material/Methods

We identified eligible studies in 5 electronic databases up to December 2014 and the reference lists of original studies and review articles were hand searched for additional articles on this topic. Summary relative risks with their 95% confidence intervals were calculated with a random-effects model. Heterogeneity was assessed using I² statistics.

Results

Fourteen randomized clinical trials met the eligibility criteria. The data suggest that the pooled successful ablation rate is 5% lower (95% CI, 1–9% lower) when using 30 mCi compared with 100 mCi (test for heterogeneity, p=0.468, I²=0.0%). In stratified analysis, ablation success rates using 30 mCi are similar to 100 mCi in Asia (SRRs=0.91; 95%CI=0.72–1.14). However, the results favor 100 mCi in Europe (SRRs=0.95; 95%CI=0.91–0.99). Ablation success rates using 30 mCi are similar to 100 mCi in patients who underwent TT/NTT (total thyroidectomy/near total thyroidectomy) (SRRs=0.96; 95%CI=0.92–1.00) and TT/STT (SRRs=0.98; 95%CI=0.73–1.31). However, the result favor 100 mCi in patients who underwent ST/HT (subtotal thyroidectomy/ hemithyroidectomy) (SRRs=0.80; 95%CI=0.65–0.99). There was no publication bias in the present meta-analysis.

Conclusions

High radioiodine activity is better than low activity in terms of successful ablation rate in low-risk differentiated thyroid cancer, but the advantage of high activity seems to only exist in patients who underwent hemithyroidectomy/subtotal thyroidectomy, but not lymph node involvement, preparation before ablation, and definition of successful ablation.

Thyroid remnant ablation in differentiated thyroid cancer: searching for the most effective radioiodine activity and stimulation strategy in a real-life scenario

OBJECTIVE

Differentiated thyroid cancer is rare, but the incidence has been increasing in the last few decades. Early treatment is based on surgery and thyroid remnant ablation (TRA) by means of radioiodine therapy. Despite radioiodine being widely used for decades, the choice of ablative activity is generally empirical and no consensus has been reached to date. The aim of our study was to compare the efficacy and safety of different radioiodine activities. In addition, we compared the ablation rate in patients treated in the hypothyroid state or after recombinant human thyroid-stimulating hormone (rhTSH) administration, retrospectively reviewing the records of 471 patients affected by differentiated thyroid cancer.

PATIENTS AND METHODS

Patients were subdivided into three groups on the basis of the different activities of radioiodine administered and taking into account the different approaches used to perform the therapy: thyroid hormonal withdrawal or rhTSH stimulation.

RESULTS

The success of TRA was evaluated 12 months later. TRA was obtained in 62/79 (78.5%) in group A (1110 MBq in the hypothyroid state), 183/190 (96.3%) in group B [2220 MBq in the hypothyroid state or after rhTSH administration: 87/90 (97%) and 96/100 (96%) patients, respectively], 199/202 (98.5%) in group C [3700 MBq in hypothyroid state or after rhTSH administration: 98/100 (98%) and 101/102 (99%) patients, respectively].

CONCLUSION

Our data demonstrate that 2220 and 3700 MBq radioiodine are more effective compared with 1110 MBq in TRA, without significant differences between 2220 and 3700 MBq or between hypothyroidism and euthyroidism. We suggest rhTSH-aided TRA with 2220 MBq iodine-131, as this approach permits efficacious treatment, thereby reducing side effects, absorbed dose to body and hospital stay.

Re-ablation I-131 activity does not predict treatment success in low- and intermediate-risk patients with differentiated thyroid carcinoma

The aim of this study was to evaluate the efficacy of different radioactive iodine (I-131) activities used for re-ablation, to compare various combinations of treatment activities, and to identify predictors of re-ablation failure in low- and intermediate-risk differentiated thyroid carcinoma (DTC) patients. The study included 128 consecutive low- and intermediate-risk patients with DTC with ablation failure after total thyroidectomy. Patient characteristics, T status, tumor size, lymph node involvement, postoperative remnant size on whole-body scintigraphy, serum thyroglobulin (Tg), thyroid-stimulating hormone (TSH), anti-Tg antibody (TgAb), and Tg/TSH ratio were analyzed as potential predictors of the re-ablation success. Re-ablation was successful in 113 out of 128 patients (88.3 %). Mean first I-131 activity was 2868 ± 914 MBq (77.5 ± 24.7 mCi) and mean second I-131 activity 3004 ± 699 MBq (81.2 ± 18.9 mCi). There was no association between the first, second, and cumulative activity with re-ablation treatment outcome. Treatment failure was associated with higher Tg levels prior to re-ablation (Tg2) (OR 1.16, 95 % CI 1.05-1.29, P = 0.003) and N1a status (OR 3.89, 95 % CI 1.13-13.41, P = 0.032). After excluding patients with positive-to-negative TgAb conversion, Tg2 level of 3.7 ng/mL predicted treatment failure with a sensitivity of 75.0 %, specificity of 80.5 %, and a negative predictive value of 97.1 %. Patients with positive-to-negative TgAb conversion had higher failure rates (OR 2.96, 95 % CI 0.94-9.29). Re-ablation success was high in all subgroups of patients and I-131 activity did not influence treatment outcome. Tg may serve as a good predictor of re-ablation failure. Patients with positive-to-negative TgAb conversion represent a specific group, in whom Tg level should not be used as a predictive marker of treatment outcome.

Diagnostic whole body scan (pre-therapy scan) in differentiated thyroid cancer: A single center community hospital experience

OBJECTIVE

Diagnostic whole body scan (pre-therapy scan) with either I-123 or I-131 (radioactive isotopes of iodine) is performed to assess the extent of thyroid cancer especially distant metastasis prior to administering the therapeutic dose of I-131. Our aim of the following study was to determine the utility of the diagnostic pre-therapy scan in the management of differentiated thyroid cancer.

MATERIALS AND METHODS

It was a case-control study carried out by retrospective chart review, of a randomly selected 100 patients with differentiated thyroid cancer who had followed in our community hospital over the course of 1 year. We collected data on multiple variables in the subjects - including age, gender, pre-operative size of the nodules, diagnosis, stage of the malignancy, size of the tumor, multifocality, lymphovascular invasion, dose of radioiodine used for remnant ablation, recurrence rates and persistence rates. Continuous variables were compared using the independent sample Mann-Whitney U-test whereas the Chi-square test was used for nominal variables.

RESULTS

The mean dose of radioactive iodine administered was 97.56 (±27.98) in the pre-therapy scan group and it was 97.23 (±32.40) in the control group. There was no difference between the two groups (P - 0.45). There was also no difference in the recurrence rates between the groups (P = 1.0). There was a trend toward a higher degree of persistent cancer in the group that had the pre-therapy scans (P - 0.086).

CONCLUSION

Pre-therapy scan may not affect the dose of radio-iodine I-131 used for remnant ablation of differentiated thyroid cancer and does not influence the recurrence rates. This was especially true with respect to I-131 remnant ablation for low risk tumors.

Different Radioiodine Dose for Remnant Thyroid Ablation in Patients With Differentiated Thyroid Cancer: A Meta-analysis

OBJECTIVE

Remnant thyroid ablation is crucial in the management of patients with differentiated thyroid cancer. However, the optimal dose of radioactive I for ablation is still controversial. This study aimed to compare the success rate of different activities of I for postoperative remnant ablation in randomized controlled trials (RCTs) and to determine the optimal dose.

PATIENTS AND METHODS

Sources were retrieved from the Cochrane Library, Medline, Embase, Scopus, and Google Scholar until March 2014. All RCTs that assessed the efficacy of different doses of I for ablation were selected. After data extraction, statistics were performed by Review Manager 5.2 software.

RESULTS

Seventeen RCTs were considered eligible, involving 3737 patients. The overall methodological quality of the studies was good. The rate of successful remnant ablation of low versus moderate I activities (risk ratio [RR], 0.89; 95% confidence interval [CI], 0.80-1.00; P = 0.06) and moderate versus high I activities (RR, 0.94; 95% CI, 0.89-1.00; P = 0.05) showed no significant differences. However, high I activities had 11% higher successful ablation rate than low activities with an RR of 0.89 (95% CI, 0.81-0.97; P = 0.008), which was significant.

CONCLUSIONS

We summarized all available randomized evidence to demonstrate that high dose of I was significantly better than low dose to achieve successful remnant thyroid ablation.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.