Long-Term Results of Fixed High-Dose I-131 Treatment for Toxic Nodular Goiter: Higher Euthyroidism Rates in Geriatric Patients

Radioiodine versus radiofrequency ablation to treat autonomously functioning thyroid nodules: a systematic review and comparative meta-analysis

PURPOSE

Radioiodine (RAI) is a well-established first-line therapy for autonomously functioning thyroid nodules (AFTN). Radiofrequency ablation (RFA) is a minimally invasive procedure that has been proposed as an alternative treatment option for hyperthyroidism caused by AFTN. Although RFA has been shown to be useful for reducing nodule volume and improving TSH levels in AFTN, no comprehensive comparative clinical studies have been proposed to evaluate the overall response to RFA treatment. The aim of this comparative systematic review and meta-analysis was to evaluate the response of RAI and RFA treatments in AFTN.

METHODS

A systematic search strategy was applied in PubMed, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov until July 2023 without time or language restrictions. Studies investigating the response to RAI and/or RFA treatment in AFTN patients 6 and/or 12 months after treatment were included. The risk of bias was assessed based on the study design. Random-effect models were used for the meta-analysis.

RESULTS

Twenty-three articles (28 reports) met the inclusion criteria and were included in the study. Overall, RAI therapy was found to have a significantly higher treatment response (94%) than RFA (59%), although the volume of AFTNs was reduced to a similar extent. In the direct comparison (n = 3 studies), RFA showed a higher risk of non-response than RAI (RR, 1.24; 95% CI, 0.94-1.63; z = 1.55; p = 0.12).

CONCLUSIONS

Our results demonstrate the superiority of RAI over RFA in terms of success rates and safety profile and confirm RAI as the first choice for the treatment of AFTNs.

Long-Term Follow-up of Patients With Autonomous Thyroid Nodules Treated With Radioiodine

PURPOSE

This article aims to describe the presentation of Plummer disease and its evolution after radioiodine treatment and determine factors that may influence treatment efficacy.

PATIENTS AND METHODS

The sample included retrospective medical records of 165 adult patients with toxic nodular goiter treated with radioiodine between 1997 and 2017, followed up at a single thyroid center.

RESULTS

The efficacy of treatment with a single dose of radioiodine was higher than 90%. The mean radioiodine activity was 28.9 ± 3.4 mCi. The mean time between radioiodine performance and hyperthyroidism resolution was 3.6 ± 3.0 months, ranging from 1-12 months. After the first year, 33.9% of the patients were under hypothyroidism, 59.4% under euthyroidism, and 6.7% under hyperthyroidism. Among the nonresponders, the variables that showed statistical difference were the presence of multinodular goiter and the radioiodine activity (mean, 25.5 ± 6.5 mCi; median, 30 [15-30 mCi]). The cumulative rate of hypothyroidism was 48.9% over 20 years of follow-up.

CONCLUSIONS

Radioiodine therapy is an effective and safe treatment. In Plummer disease, high rates of euthyroidism are expected after the radioiodine treatment. Therapeutic failure was observed mainly in patients with larger multinodular goiters treated with lower doses of radioiodine. The evolution to hypothyroidism was mostly observed in younger patients with larger and uninodular goiters.

Fixed 30 mCi (1110 MBq) 131I-iodine therapy in autonomously functioning nodules: Single toxic nodule as a predictive factor of success

Aims:

The aim of this study is to evaluate the efficacy of a fixed 30 mCi (1110 MBq) ¹³¹I-iodine dose for the treatment of hyperthyroidism due to uninodular or multinodular toxic goiter and identify predictors of success.

Materials and Methods:

Fifty-nine patients diagnosed with nonautoimmune toxic goiter were treated with a fixed 30 mCi dose of ¹³¹I-iodine and were followed at a tertiary service between 2000 and 2016. The therapy was considered successful if the patient reached euthyroidism or hypothyroidism without needing an extra ¹³¹I-iodine dose or antithyroid drugs for at least 1 year after the radioiodine therapy (RIT).

Results:

Patients with a single toxic nodule were younger at diagnosis (52 vs. 63 years; P = 0.007), presented a shorter disease duration until RIT (2 vs. 3.5 years; P = 0.007), smaller total thyroid volume (20 vs. 82 cm³; P = 0.044), and lower pre-RIT thyroid uptake (P = 0.043) than patients with multinodular goiter. No significant difference was seen with antithyroid drug use, thyroid-stimulating hormone and free thyroxine level, and follow-up after RIT. After RIT, 47 patients (79.66%) met the success criteria, and 12 (20.33%) remained hyperthyroid. Among the success group, 32 (68.08%) reached euthyroidism, while 31.92% developed hypothyroidism after 1 year. Patients with single toxic nodules who achieved success after RIT presented smaller nodules (2.8 vs. 5.75 cm; P = 0.043), while the pre-RIT thyroid uptake was higher among patients with multinodular toxic goiter who achieved success after RIT (5.5% vs. 1.5%; P = 0.007). A higher success rate was observed among patients with a single toxic nodule than those with a toxic multinodular goiter (92.3% vs. 55%; P = 0.001), and a single toxic nodule presentation was found to be an independent predictor of success (P = 0.009).

Conclusions:

The fixed 30 mCi ¹³¹I-iodine dose was particularly effective in the group of patients with single autonomously functioning nodule rather than the group with multiple nodules. A single toxic nodule was an independent predictor of treatment success.

Dosimetry-guided radioiodine therapy of hyperthyroidism: long-term experience and implications for guidelines

BACKGROUND

Long-term follow-up after radioactive iodine therapy (RIT) for Graves' disease and toxic thyroid autonomy is incompletely addressed by current guidelines. We retrospectively analyzed the clinical course of 1233 out of 1728 consecutive Graves' disease (n = 536) and thyroid autonomy (n = 1192) patients after dosimetry-guided RIT to optimize follow-up.

METHODS

Patients were referred between 1990 and 2018; follow-up was monitored according to available electronic registers with medical reports, including autopsies from 9 hospitals and 10 residential care homes.

RESULTS

In total, 495/1728 cases were censored because of incomplete 6-month follow-up data. The conversion rates to hypothyroidism in Graves' disease and different forms of thyroid autonomy can be deconvoluted into two follow-up periods: first year after RIT and afterward. The conversion rate in Graves' disease was significantly higher than that in all thyroid autonomy subgroups during the first year but almost identical afterwards. Thyroxine substitution started between 10 and 7900 days after RIT at thyroid stimulating hormone between 0.11 and 177 µU/ml.

CONCLUSIONS

We advise earlier (2-3 weeks) first follow-up checks after RIT in all Graves' disease patients and thyroid autonomy under antithyroid drugs (ATD) and re-checks every 2-4 weeks until conversion to hypothyroidism during the first year. The first check in thyroid autonomy without ATD should be after 3-4 weeks with re-checks every 4-6 weeks. After 1 year, both groups can be re-checked every 4-6 months over the next 5 years. The success rate of RIT in thyroid autonomyincreases with age but the history of RIT is rapidly lost during follow-up.

Long-term Effects of Radioiodine in Toxic Multinodular Goiter: Thyroid Volume, Function, and Autoimmunity

CONTEXT

Long-term studies evaluating the treatment of toxic multinodular goiter (TMNG) with fixed activities of radioiodine (RAI) are lacking.

OBJECTIVE

The objective of this work is to describe the effects of 15 mCi on thyroid volume, function, and autoimmunity in the long term.

DESIGN AND SETTING

A population-based, retrospective analysis with up to 12 years of follow-up was conducted in Siena, Italy.

PARTICIPANTS

Adult patients (n = 153) with TMNG, naive to RAI, were included.

METHODS

Evaluation was performed of thyroid function, antithyroid antibodies, and ultrasound scans before and yearly after RAI.

MAIN OUTCOME MEASURES

Evaluations included hyperthyroidism cure, hypothyroidism, volume reduction, nadir and regain, and antibody titer change.

RESULTS

The study revealed mean volume reductions greater than or equal to 50% at 3 years after RAI; the greatest annual reduction was observed during the first year (30 ± 17.8%; P < .001). Most patients (60%) achieved their volume nadir 3 to 6 years after RAI. Although 22% patients showed volume regain, the net reduction was statistically significant as late as 9 years after RAI (P = .005). The mean time to hypothyroidism was 2.7 ± 2.4 years, and it was associated with greater reductions in volume (P = .01). During the first 3 years after treatment, hyperthyroid patients decreased approximately by 50% per year without additional RAI. There was no statistically significant association of antibody titers with thyroid function except for antithyrotropin receptor antibodies and hyperthyroidism (P = .004). At the end of follow-up there were 61.6% euthyroid patients, 11% hyperthyroid (4.8% overt), and 27.4% hypothyroid patients (2.7% overt). Hyperthyroidism was cured in 89%.

CONCLUSIONS

The treatment of TMNG with 15 mCi of RAI induced low hypothyroidism rates while providing high cure rates and significant volume reduction, which was maintained in the long term.

Changes in the size of the thyroid in patients with benign non-toxic multinodular goiter after radioactive iodine therapy

Background: Multinodular goiter (MNG) is regarded as one of the most common causes of hyperthyroidism, particularly in areas of mild-to-moderate iodine deficiency. The present study aims to explore the effects of the radioactive iodine (RAI) therapy on benign non-toxic MNG and evaluate its side effects.

Methods: Patients with benign non-toxic MNG entered the study. Ultrasonography was applied to calculate the percentage of the decrease in the size of the thyroid before and six months minimum after the treatment. Chi-square, Mann-Whiteny-U and T-test were done using SPSS v.18.0 (p<0.05).

Results: The volumes of the thyroid lobes and nodules decreased significantly due to RAI therapy (p<0.001). The total volume of the thyroid, volume of the right nodule, and volume of the left nodule decreased by 77.8%, 40.7%, and 34.6% respectively.

Conclusion: According to the results of the current study, RAI therapy is an effective treatment method although it has short-term side effects. This treatment option is recommended for patients with benign non-toxic MNG, notably those who cannot be a candidate for surgery. This treatment affects the size of the thyroid and its nodules significantly and decreases almost all of the complications.