Radio-iodine therapy in differentiated thyroid cancer: indications and procedures

Advances and challenges in thyroid cancer: The interplay of genetic modulators, targeted therapies, and AI-driven approaches

Thyroid cancer continues to exhibit a rising incidence globally, predominantly affecting women. Despite stable mortality rates, the unique characteristics of thyroid carcinoma warrant a distinct approach. Differentiated thyroid cancer, comprising most cases, is effectively managed through standard treatments such as thyroidectomy and radioiodine therapy. However, rarer variants, including anaplastic thyroid carcinoma, necessitate specialized interventions, often employing targeted therapies. Although these drugs focus on symptom management, they are not curative. This review delves into the fundamental modulators of thyroid cancers, encompassing genetic, epigenetic, and non-coding RNA factors while exploring their intricate interplay and influence. Epigenetic modifications directly affect the expression of causal genes, while long non-coding RNAs impact the function and expression of micro-RNAs, culminating in tumorigenesis. Additionally, this article provides a concise overview of the advantages and disadvantages associated with pharmacological and non-pharmacological therapeutic interventions in thyroid cancer. Furthermore, with technological advancements, integrating modern software and computing into healthcare and medical practices has become increasingly prevalent. Artificial intelligence and machine learning techniques hold the potential to predict treatment outcomes, analyze data, and develop personalized therapeutic approaches catering to patient specificity. In thyroid cancer, cutting-edge machine learning and deep learning technologies analyze factors such as ultrasonography results for tumor textures and biopsy samples from fine needle aspirations, paving the way for a more accurate and effective therapeutic landscape in the near future.

The effect of thyroid hormone withdrawal performed to evaluate the success of I-131 ablation on quality of life and psychological symptoms in female patients with low-risk differentiated thyroid cancer

Aim: There is a need to evaluate the treatment response in patients who have undergone radioiodine treatment (RIT) for differentiated thyroid cancer. Diagnostic tests that are used for this purpose include radioiodine whole-body scan (WBS) and serum thyroglobulin (Tg) measurement, which are most accurate during thyroid-stimulating hormone (TSH) stimulation. However, temporary discontinuation of thyroid hormone therapy to increase TSH (withdrawal) may be associated with the morbidity of hypothyroidism. The study aimed to show the effects of thyroid hormone withdrawal (THW) on quality of life and psychological symptoms in female patients with low-risk, well-differentiated papillary thyroid cancer. Methods: We applied the short form-36 (SF-36) and Symptom Checklist-90-R (SCL-90-R) questionnaires to the patients in the euthyroid state who have referred a median of 9 months (6-13 months) after RIT to perform a dWBS and to evaluate stimulated Tg. We applied the same questionnaire again when thyroid-stimulating hormone (TSH) was > 30 μIU/mL 4 weeks after THW (hypothyroid state). Results: 52 patients were evaluated (median age 48 years, range 23-65 years). There was a statistically significant worsening in anxiety, psychosis, additional items, and general symptoms of the SCL-90-R questionnaire, physical functioning, role limitation due to physical health, energy/fatigue, emotional well-being, social function, and general health change in the SF-36 questionnaire. Conclusions: THW worsened the patients’ psychological symptoms and quality of life. To reduce the side effects of hypothyroidism, treatment response assessment with TSH stimulation should be used only in a selected group of patients with a higher risk of recurrence.

A model to determine at-home restrictions for cats after treatment of hyperthyroidism with radioiodine

OBJECTIVES

Felinehyperthyroidism is the most common endocrine disease of older cats and radioiodine is considered to be the gold standard treatment. Isolation periods following treatment vary depending on both individual treatment facilities and the relevant legislation of the country; therefore, there is no recognised standardised protocol defining the length of isolation. This work describes how our institution validated that its owner restrictions met dose constraints by using a model of iodine retention to calculate the required duration and nature of owner restrictions.

MATERIALS AND METHODS

The retained radioactivity of cats at the point of discharge was used to simulate the radiation dose to owners in the 90 days following release. The model created was used to calculate the minimum duration of isolation for a range of administered activities and owner restrictions.

RESULTS

Using the model, it was found that when injected with the maximum dose used, 222 MBq radioiodine, it was possible to release cats after 14 days of isolation and keep owner doses below 0.30 mSv (whole-body effective dose constraint for a single radiation source) with some restrictions. It was possible to release after 23 days with no restrictions.

CLINICAL SIGNIFICANCE

The present study provides clinicians with a consistent and verified method in which they can calculate the isolation periods for radioiodine-treated cats.

Differentiated thyroid cancer theranostics: radioiodine and beyond

The term theranostics is the combination of a diagnostic tool that helps to define the right therapeutic tool for specific disease. It signifies the "we know which sites require treatment (diagnostic scan) and confirm that those sites have been treated (post-therapy scan)" demonstrating the achievable tumor dose concept. This term was first used by John Funkhouser at the beginning of the 90s, at the same time the concept of personalized medicine appeared. In nuclear medicine, theranostics is easy to apply and understand because of an easy switch from diagnosis to therapy with the same vector. It helps in maximizing tumor dose and sparing normal tissue with high specific and rapid uptake in metastasis. The oldest application of this concept is radioactive iodine I-131 (RAI). The first treatment based on the theranostic concept was performed on thyroid cancer patients with RAI in 1946. From then on management of differentiated thyroid cancer (DTC) has evolved on the multimodality concept. We now use the term "our" patient instead of "my" patient to signify this. However, the initial surgical management followed by RAI as per the theranostics has remained the mainstay in achieving a cure in most of DTC patients. The normal thyroid cells metabolise iodine, the principle of which is utilized in imaging of the thyroid gland with isotopes of iodine. RAI treatment of DTC is based on the principle of sodium iodide symporter (NIS) expressing thyroid cells with DTC cells having the ability of trapping circulating RAI successfully helping in treatment of residual and metastatic disease. NIS is usually negative in poorly differentiated cells and is inversely proportional to Glucose transporter receptor Type 1 expression. Both positive and negative NIS are the key components of the theranostic approach in treatment of DTC. Presence or absence of NIS is documented by either whole body iodine scintigraphy (WBS) or 2-deoxy-2(¹⁸F) fludeoxyglucose (FDG) positron emission tomography computed tomography (PET-CT). Currently, single photon emission CT and CT (SPECT-CT) has significantly improved the precision and sensitivity of whole body iodine scintigraphy with its capability of accurate localization of disease foci whether iodine avid or non-avid. This has helped in a more personalized approach in treatment. This review will give an overview of the role of NIS in the theranostic approach to management with RAI, its current status and also the molecular approach to treatment in RAI refractory disease.

Usefulness of (131)I-SPECT/CT and (18)F-FDG PET/CT in Evaluating Successful (131)I and Retinoic Acid Combined Therapy in a Patient with Metastatic Struma Ovarii

Metastatic struma ovarii is an extremely rare disease, and the treatment of choice has not been established. Here, we introduce the case of a 36-year-old female pregnant patient with metastatic struma ovarii. Initial treatment was an exploratory laparotomy to remove multiple peritoneal masses. After delivery, a total thyroidectomy was done for the further (131)I-therapy. (131)I-SPECT/CT and (18) F-FDG PET/CT showed multiple hepatic metastases and extensive peritoneal seeding nodules. Multiple (131)I and retinoic acid combination therapies were performed, resulting in marked improvement. (131)I-SPECT/CT and (18) F-FDG PET/CT were quite useful for evaluating the biologic characteristics of the metastases.

Risk factors for developing hyponatremia in thyroid cancer patients undergoing radioactive iodine therapy

Background

Due to the alarming increase in the incidence of thyroid cancer worldwide, more patients are receiving postoperative radioactive iodine (RAI) therapy and these patients are given a low-iodine diet along with levothyroxine withdrawal to induce a hypothyroid state to maximize the uptake of RAI by thyroid tissues. Recently, the reported cases of patients suffering from life-threatening severe hyponatremia following postoperative RAI therapy have increased. This study aimed to systematically assess risk factors for developing hyponatremia following RAI therapy in post-thyroidectomy patients.

Methods

We reviewed the medical records of all thyroid cancer patients who underwent thyroidectomy and postoperative RAI therapy from July 2009 to February 2012. Demographic and biochemical parameters including serum sodium and thyroid function tests were assessed along with medication history.

Results

A total of 2229 patients (47.0±11.0 years, female 76.3%) were enrolled in the analysis. Three hundred seven patients (13.8%) of all patients developed hyponatremia; 44 patients (2.0%) developed moderate to severe hyponatremia (serum Na⁺≤130 mEq/L) and another 263 (11.8%) patients showed mild hyponatremia (130 mEq/L<serum Na⁺≤135 mEq/L). In univariate analysis, old age, female sex, presence of hypertension, presence of diabetes, use of thiazide diuretics, use of angiotensin receptor blocker or angiotensin-converting enzyme inhibitors, lung metastasis, and hyponatremia and lower estimated glomerular filtration rate at the start of RAI therapy were significantly associated with hyponatremia in patients undergoing RAI therapy after total thyroidectomy. Multivariate analysis showed that old age, female sex, use of thiazide diuretics, and hyponatremia at the initiation of RAI therapy were independent risk factors for the development of hyponatremia.

Conclusion

Our data suggest that age greater than 60 years, female sex, use of thiazide, and hyponatremia at the initiation of RAI therapy are important risk factors for developing hyponatremia following RAI therapy in post-thyroidectomy patients.

Severe hyponatremia following radioactive iodine therapy in patients with differentiated thyroid cancer

BACKGROUND

Symptomatic hyponatremia in association with radioactive iodine (RAI) therapy for differentiated thyroid cancer has rarely been reported. Due to the increasing incidence of thyroid cancer worldwide, more patients are now receiving postoperative RAI therapy. We report two cases of life-threatening severe hyponatremia in association with RAI therapy.

SUMMARY

Two elderly female patients who had bilateral thyroidectomies for their thyroid cancer underwent a low-iodine diet and levothyroxine withdrawal for two weeks prior to RAI therapy. Upon admission, the patients were given 130 mCi (4810 MBq) and 150 mCi (5550 MBq) of (131)I respectively, and oral hydration (two to three liters of water daily) to increase the frequency of emptying the bladder of RAI. Both patients completed their RAI therapy without significant complications and were discharged from hospital. Two days after discharge, both patients were admitted to the emergency room with complaints of severe nausea and dizziness. Initial laboratory tests revealed that they were in a hypothyroid state and had severe hyponatremia with a serum sodium level of 108 mEq/L. The symptomatic hyponatremia responded to intravenous hypertonic saline infusion and thyroid hormone replacement, and the patients made a full recovery. The low-iodine diet and hypothyroid state with overzealous hydration in the setting of RAI therapy may have provoked severe hypotonic hyponatremia.

CONCLUSION

Hypothyroid patients after undergoing RAI therapy, especially the elderly, are at an increased risk for serious hyponatremia and should be monitored closely.

New developments in the diagnosis and treatment of thyroid cancer

Thyroid cancer exists in several forms. Differentiated thyroid cancers include those with papillary and follicular histologies. These tumors exist along a spectrum of differentiation, and their incidence continues to climb. A number of advances in the diagnosis and treatment of differentiated thyroid cancers now exist. These include molecular diagnostics and more advanced strategies for risk stratification. Medullary cancer arises from the parafollicular cells and not the follicular cells. Therefore, diagnosis and treatment differs from those of differentiated thyroid tumors. Genetic testing and newer adjuvant therapies have changed the diagnosis and treatment of medullary thyroid cancer. This review will focus on the epidemiology, diagnosis, workup, and treatment of both differentiated and medullary thyroid cancers, focusing specifically on newer developments in the field.

Calibration of Traceable Solid Mock (131)I Phantoms Used in an International SPECT Image Quantification Comparison

The International Atomic Energy Agency (IAEA) has organized an international comparison to assess Single Photon Emission Computed Tomography (SPECT) image quantification capabilities in 12 countries. Iodine-131 was chosen as the radionuclide for the comparison because of its wide use around the world, but for logistical reasons solid (133)Ba sources were used as a long-lived surrogate for (131)I. For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared. We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard. This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders. This level of uncertainty allows for these sources to be used for the intended comparison exercise, as well as in other SPECT image quantification studies.

Relationship between estimated glomerular filtration rate and biological half-life of 131I. Retrospective analysis in patients with differentiated thyroid carcinoma

AIM

This retrospective study sought to investigate the relationship between biological half-life (t1/2 biol) of 131I and estimated glomerular filtration rate (eGFR) in patients with thyroid carcinoma.

PATIENTS, METHODS

96 patients with differentiated thyroid carcinoma (69 women, 27 men, mean age 64.0 ± 13.6 years) and diagnostic and therapeutic administration of 131I were considered. Patients with pronounced specific iodine storage were not included in the study. The eGFR was estimated according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, the t1/2 biol via dosimetry. Patients were subdivided in groups with normal clearance (NC) (n = 37, 38.5%), medium clearance (MC) (n = 48, 50.0%), and low clearance (LC) (n = 11, 11.5%) (eGFR ≥ 90; 60-89; 15-59 ml/min per 1.73 m2, respectively). The relationship between eGFR and t1/2 biol of 131I was modeled using a power function.

RESULTS

The groups significantly differed in terms of age (NC 53.8, MC 68.6, and 78.0 years, respectively), serum creatinine levels (NC: 0.71; MC: 0.85; LC: 1.18 mg/dl), and t1/2 biol (NC: 0.53; MC: 0.71; LC: 1.01 days). The t1/2 biol was significantly influenced only by eGFR, and not by age, gender, or body weight. The relationship between t1/2 biol of 131I and eGFR was described by the formula t1/2 biol = 20.3 · eGFR-0.782.

CONCLUSIONS

The calculated relationship between renal function and t1/2 biol of 131I can be used in principle to estimate a dose reduction for patients with renal insufficiency. The model, however, gives erroneous results in individual cases and therefore a routine utilization cannot be recommended. Prospective studies are necessary, based on larger patient numbers and more accurate methods for dose rate measurement and GFR.

Estimation of true serum thyroglobulin concentration using simultaneous measurement of serum antithyroglobulin antibody

We investigated the analytical interference of antithyroglobulin antibody (TgAb) to thyroglobulin (Tg) measurement and tried to convert measured Tg concentration to true Tg concentration using a mathematical equation which includes a concentration of TgAb. Methods. Tg was measured by immunoradiometric assay and TgAb by radioimmunoassy. Experimental samples were produced by mixing Tg and TgAb standard solutions or mixing patients' serum with high Tg or high TgAb. Mathematical equations for prediction of expected Tg concentration with measured Tg and TgAb concentrations were deduced. The Tg concentration calculated using the equations was compared with the expected Tg concentration. Results. Measured Tg concentrations of samples having high TgAb were significantly lower than their expected Tg concentration. Magnitude of TgAb interference with the Tg assay showed a positive correlation with concentration of TgAb. Mathematical equations for estimation of expected Tg concentration using measured Tg and TgAb concentrations were successfully deduced and the calculated Tg concentration showed excellent correlation with expected Tg concentration. Conclusions. A mathematic equation for estimation of true Tg concentration using measured Tg and TgAb concentration was deduced. Tg concentration calculated by use of the equation might be more valuable than measured Tg concentration in patients with differentiated thyroid cancer.

Postsurgical pathology reporting of thyroid cancer in New South Wales, Australia

BACKGROUND

Clear, accurate, and complete reporting of postsurgical pathology is crucial for the correct evaluation and management of thyroid cancer patients. This study aimed to describe the completeness, as defined by international guidelines, of pathology reporting in a cohort of newly diagnosed thyroid cancer patients in New South Wales (NSW) and to identify factors associated with the completeness of reports.

METHODS

Postsurgical pathology reports, held by the NSW Central Cancer Registry, for 448 thyroid cancer patients were reviewed. Presence or absence of recommended key features (tumor histology type, maximum dimension, focality, completeness of excision, extrathyroidal extension, lymphovascular invasion, and lymph node involvement) was recorded. Associations between the number of key items reported and several patient characteristics were investigated.

RESULTS

For 285 (63.6%) patients one or more key pathological features were missing, with 177 (39.5%) missing one only, 88 (19.6%) missing two, and 20 (4.5%) missing three or more. Extrathyroidal extension was the most poorly reported key feature, being present in only 228 (50.9%) reports [95% confidence interval 46.2, 55.6]. Pathology reports were less complete for patients with small tumor size (p<0.001) or localized spread (p<0.001). Synoptic reports were significantly more complete than narrative-style reports (98.3% vs. 27.1%, p<0.001).

CONCLUSIONS

Postsurgical pathology reporting of differentiated thyroid cancer in NSW was found to be far from complete, with 64% of reports missing information on at least one feature that is considered internationally to be a critical factor in the prognosis and treatment of thyroid cancer patients. Synoptic reporting reduces the number of key features missing from pathology reports.

Cumulative doses of radioiodine in the treatment of differentiated thyroid carcinoma: knowing when to stop

OBJECTIVE

Evaluate the efficacy of cumulative doses (CDs) of 131I-iodide therapy (RIT) in differentiated thyroid cancer (DTC).

SUBJECTS AND METHODS

The probability of progressive disease according to CDs was evaluated in patients < 45 years old and > 45 years old and correlated to tumor-node-metastasis (TNM), thyroglobulin values, histological types and variants, age, and zduration of the disease.

RESULTS

At the end of a follow-up period of 69 ± 56 months, 85 out of 150 DTC patients submitted to fixed doses RIT had no evidence of disease, 47 had stable disease and 18 had progressive disease. Higher CDs were used in the more aggressive variants (p < 0.0001), higher TNM stages (p < 0.0001), and follicular carcinomas (p = 0.0034). Probability of disease progression was higher with CDs > 600 mCi in patients > 45 years old and with CDs > 800 mCi in patients < 45 years.

CONCLUSION

Although some patients may still respond to high CDs, the impact of further RIT should be carefully evaluated and other treatment strategies may be warranted.

Multifocality in well-differentiated thyroid carcinomas calls for total thyroidectomy

BACKGROUND

Multifocality is an important factor when recommending surgery for papillary thyroid cancer (PTC). The aim of this study is to assess the incidence and characterize the spread pattern of multifocal PTC (mPTC) in patients undergoing total thyroidectomy.

METHODS

All thyroidectomies performed between 2003 and 2008 were reviewed identifying 289 patients. Data were obtained for demographics, clinical data, and histopathological findings.

RESULTS

Of the patients with papillary carcinoma, mPTC was identified in 150 patients (57%), of which 71% had lesions in the contralateral lobe. There were no significant differences in multifocality rate for gender, pathology type, and all tumor size subgroups including ≤1 cm. Pathology examination of representative sections versus the entire gland examination resulted in a significantly lower incidence of contralateral disease (P = .04).

CONCLUSIONS

Multifocal and contralateral lesions are common in PTC and their incidence is not related to tumor size. Pathology entire gland examination is strongly recommended to properly assess the rate of mPTC.

Judicious use of recombinant TSH in the management of differentiated thyroid carcinoma

OBJECTIVE

To evaluate the feasibility of using recombinant human TSH (rhTSH) in conjunction with ¹³¹I to treat patients with differentiated thyroid carcinoma.

METHODS

Between July 2003 and April 2009, 14 patients [mean age, 39.1 years (range 14-71 years)], of whom seven were treated for remnant ablation and seven for irresectable or metastatic disease, received rhTSH-aided ¹³¹I therapy. None had an adequate rise in TSH. The mean ¹³¹I dosage administered was 5206.3 MBq. Baseline thyroglobulin/anti-thyroglobulin (Tg/anti-Tg) and TSH levels were documented. rhTSH (0.9 mg) was given intramuscularly on days 1 and 2, and TSH levels were recorded. ¹³¹I was given when the TSH level rose to >30 μIU/ml. Tg/anti-Tg levels were measured at 3-month intervals. A ¹³¹I whole-body scan (¹³¹I scan) was performed 6 or 12 months after treatment.

RESULTS

The baseline median valid Tg and TSH levels were 76.2 ng/ml (range 14.1 to >30000) and 3.63 μIU/ml (range 1.36-11.0), respectively. The rise in TSH level was 34.8-96.9 μIU/ml after the first rhTSH injection and 33.1 to >75 μIU/ml after the second injection. The post-therapy ¹³¹I scan showed uptake at disease sites in all patients, indicating the initial empirical adequacy of treatment. Follow-up ¹³¹I scan was positive for four patients, but negative for three of these patients after subsequent therapy. Complete resolution of disease was seen in eight patients and partial resolution in four after 3 months of therapy; one had stable disease; and in one patient with progressive disease, complete resolution was achieved after repeated ¹³¹I doses with thyroxine withdrawal. After a median follow-up of 39.2 months, all patients were alive and no disease recurrence was observed. The overall response rate at 3 months was 86% and had improved to 93% at the time of this review. The final ablation rate in seven patients was 100%. Apart from notable neck swelling in four patients, which was responsive to medication, and headache in two patients, no significant short-term side-effects of therapy were seen.

CONCLUSION

In our setting, the use of rhTSH-aided ¹³¹I ablation and treatment was safe and effective.

The pan-DAC inhibitor LBH589 is a multi-functional agent in breast cancer cells: cytotoxic drug and inducer of sodium-iodide symporter (NIS)

New drugs with anti-tumor activity, also able to modify the expression of selected molecules, are under evaluation in breast cancer which is becoming resistant to conventional treatment, or in metastatic disease. The sodium-iodide symporter (NIS), which mediates iodide uptake into thyroid cells, and is the molecular basis of radioiodine imaging and therapy in thyroid cancer, is also expressed in a large portion of breast tumors. Since NIS expression in breast cancer is not sufficient for a significant iodide uptake, drugs able to induce its expression and correct function are under evaluation. In the present study, we report for the first time that the pan-deacetylase (DAC) inhibitor LBH589 (panobinostat) significantly induced NIS, both as mRNA and as protein, through the increase of NIS promoter activity, with the final consequence of obtaining a significant up-take of iodide in MCF7, T47D, and MDA-MB231 breast cancer cells. Moreover, we observed that LBH589 causes a significant reduction in cell viability of estrogen-sensitive and -insensitive breast cancer cells within nanomolar range. The anti-tumor effect of LBH589 is sustained by apoptosis induction and cell cycle arrest in G(2)/M. In conclusion, our data suggest that LBH589 might be a powerful tool in the management of breast cancer due to its multiple effects and support a potential application of LBH589 in the diagnosis and treatment of this disease.