Use Of Radioactive Iodine Research Articles

Theranostics Nuclear Medicine in Prostate Cancer

Theranostic Nuclear Medicine is based on the idea of combining the same molecule (or drug) with different radioisotopes for both diagnosis and treatment, a concept that emerged in the early 1940s with the use of radioactive iodine for thyroid diseases. Theranostic Nuclear Medicine has since expanded to diseases of higher incidence, such as prostate cancer, with several imaging methods used to assess the extent of the disease and the corresponding radiopharmaceuticals used for treatment. For example, by detecting osteoblastic metastases by bone scintigraphy, corresponding radiopharmaceuticals with therapeutic properties can be administered to eliminate or reduce pain associated with metastases and/or determine overall survival gain. The purpose of this review is to discuss the role of Theranostic Nuclear Medicine in prostate cancer, addressing the main diagnostic imaging studies with their corresponding treatments in the Theranostic model.

Association of Radioactive Iodine Administration With Outcome Among Patients With Low-Risk Differentiated Thyroid Cancer: A Real-World Data Analysis.

Despite the generally favourable long-term prognosis of low-risk differentiated thyroid cancer (DTC), questions remain about disease-free survival (DFS) after initial treatment, particularly regarding the use of radioactive iodine (RAI). Although there are RCT trial confirming that RAI ablation therapy is not superior to follow-up in terms of the 3-year DFS rate in low-risk thyroid cancer, its longer-term prognosis remains to be established. The objective of this study was to assess the impact of RAI ablation on the presence of structural persistent/recurrent disease in patients with low-risk DTC. We retrospectively identified 720 low-risk DTC patients who had undergone total or near-total thyroidectomy (TT) at a tertiary medical centre between January 2008 and July 2018. Propensity scores were calculated using a multivariable logistic regression model that accounted for age, sex, tumour size, neck dissection, multifocality, capsular invasion and lymph node (LN) metastasis. We compared DFS between patients who received RAI and those who did not using log-rank tests and multivariate Cox analyses. Subgroup analyses were also conducted. Of the total cohort, 180 (25.0%) patients received RAI, while 540 (75.0%) did not before matching. The median follow-up duration was 59.5 months. After matching, the RAI group comprised 135 (39.8%) patients and the non-RAI group comprised 204 (60.2%) patients. In the entire cohort, the 5-year DFS rate was 97.6% for patients receiving RAI compared to 96.8% for those not receiving RAI (p = 0.704). In the matched cohort, the rates were 98.5% and 95.6%, respectively (p = 0.090). Matched multivariate Cox analysis demonstrated that RAI was neither significantly nor independently associated with DFS (hazard ratio [HR] = 0.29; 95% CI 0.06-1.37; p = 0.118). Further subgroup analyses reaffirmed that RAI ablation did not significantly reduce the risk of developing structural persistent/recurrent disease. Administering RAI ablation following TT did not result in improved DFS for low-risk DTC patients. Our findings suggest that decisions regarding RAI should be made judiciously to avoid overtreatment in this clinical scenario.

8135 A Rare Case of Late Recurrence of Graves’ Disease Decades After Radioactive Iodine Therapy: Is it Really a Definitive Treatment?

Abstract Disclosure: K.S. Hill: None. R. Osman: None. Graves’ disease (GD) is the most common cause of hyperthyroidism in the US and worldwide. Radioactive iodine (RAI) therapy has excellent success rates in treatment of GD. Studies have demonstrated that RAI successfully treats GD with a single session in the majority of cases. Recurrence after RAI, if it occurs, is most commonly seen in the first year after RAI. However, this is rare particularly in patients who have developed evidence of successful treatment in the form of post-ablative hypothyroidism. Only a few case reports have demonstrated recurrence of GD more than 10 years after treatment of GD with RAI and development of post-ablative hypothyroidism. We report a case of GD recurrence approximately 30 years after ablation. A 69 y/o woman presented for evaluation of hyperthyroidism and newly discovered thyroid nodule. Her history was significant for GD with orbitopathy diagnosed in the early 1990s and treated with RAI. Following the ablation, she developed hypothyroidism and was managed for over 20 years on levothyroxine therapy. In recent years she began to develop symptoms of palpitations and heat intolerance with biochemical evidence of thyrotoxicosis despite reductions in her levothyroxine dose. She also developed recurrence of her orbitopathy, confirmed by ophthalmology. During this time, a neck CT incidentally described an atrophic thyroid gland with a 9 mm soft tissue nodule in the left thyroid bed. Follow up ultrasound showed a 1.1 cm nodule with increased vascularity in the left thyroid bed with an otherwise atrophic gland and no lymphadenopathy. Her levothyroxine was stopped for one month in preparation for a thyroid uptake scan, during which TSH increased to 15 mcU/mL. Scan showed overall severely decreased radioactive iodine uptake of the gland consistent with prior ablation although there was a faint uptake most focally conspicuous on the left side inferiorly. Thyroid stimulating immunoglobulin (TSI) was elevated at 1.35 IU/L (Ref 0.00-0.55). After discussion with the patient, the decision was made for surgical treatment with thyroidectomy. Pathology was benign. She was continued on her prior dose of levothyroxine 75 mcg daily however now with clinical and biochemical evidence of hypothyroidism requiring continued increase in levothyroxine dose to normalize TSH levels. GD is the most common cause of hyperthyroidism and RAI therapy is the most common definitive treatment for GD in the US. Recurrence of GD after ablative hypothyroidism is rare, particularly in the case of late recurrence decades after ablation. Only a few cases are reported in the literature, ours with the longest interval-to-relapse. Recurrence of orbitopathy may be the first clue. Our case highlights the need to continue to monitor clinically for recurrence of Graves’ disease long after RAI use. Presentation: 6/3/2024

Thyroid cancer epidemiology in Ireland from 1994 to 2019 – Rising diagnoses without mortality benefit

BackgroundThe epidemiology and management of thyroid cancer has changed radically in the recent past, with rising international incidence of early-stage papillary thyroid cancer (PTC) in particular. In this paper, we review the epidemiology of thyroid cancer in Ireland. MethodsA retrospective cohort study of National Cancer Registry of Ireland data, 1994–2019. ResultsRecords from 4158 patients were analysed. 73 % (n = 3040) were female. The average age was 50.4 years. Patient sex did not change over time (p = 0.662), while age decreased significantly (p < 0.0001). The most common diagnoses were PTC (n = 2,905, 70 %) and follicular thyroid carcinoma (n = 549, 13 %). Incidence rose over threefold (1.8–6.2 cases/100000 person-years). The incidence of T1 PTC rose over twelvefold (0.169–2.1 cases/100000 person-years), while the incidence of stage III and IV disease did not change significantly. Five-year disease-specific survival (DSS) was 85 % and varied significantly by diagnosis – 97 % for PTC versus 5 % for anaplastic thyroid carcinoma. Survival did not change significantly over time. Male sex was a risk factor for more advanced disease (p < 0.0001) but did not independently predict overall survival except in PTC (HR 1.6, p = 0.03). The use of radioactive iodine declined markedly from 49 % to 12.5 %. RAI improved DSS for PTC patients aged over 55 years (p = 0.02) without a notable effect on survival for those under 55 years (p = 0.99). ConclusionThe epidemiology and management of thyroid cancer in Ireland has changed dramatically in a manner reflective of international trends.

Consider or not consider: the unsolved question on the use of radioactive iodine for differentiated thyroid cancer with low to intermediate risk of recurrence.

Surgery stands as the cornerstone treatment for differentiated thyroid cancer (DTC). After surgery, radioactive iodine (RAI) administration is primarily recommended for high-risk patients and commonly employed to address residual disease or mitigate the risk of recurrence. However, the optimal application of RAI in cases categorized as low to intermediate risk is still uncertain. This study aims to assess the indication of post-surgical RAI treatment specifically in patients diagnosed with DTC falling within the low to intermediate risk category for recurrent disease. retrospective analysis of consecutive patients with DTC falling within the low to intermediate risk category for recurrence and diagnosed between 2009-2015. Patients were categorized into either treated or untreated with RAI. Treatment effect was assessed by the inverse-probability weighted regression adjustment (IPWRA), by balancing the distribution of factors influencing outcome and treatment assignment. after surgery, 328 patients (69.9%) were treated with RAI while 141 (30.1%) were left untreated. Across the entire cohort, 44 individuals (9.4%) displayed biochemical or structural disease after a median time of 17.5 months following diagnosis. Recurrent disease was more prevalent in patients who underwent RAI treatment compared to those untreated (12.5% vs 2.1%, respectively, p < 0.001). Factors independently associated with recurrent disease, identified through multivariate logistic regression analysis, included lymph node metastases (pN1) (OR = 4.07; 95% CI 1.84-8.97), male sex (OR = 2.71; 95% CI 1.31-5.59), tumor size (OR = 1.03; 95% CI 1.00-1.06), and microscopic extrathyroidal extension (OR = 2.36; 95% CI 1.15-4.81). IPWRA analysis revealed that the occurrence of recurrent disease was 9.6% (95% CI = 6.3-12.9) in RAI-treated patients and 15.9% (95% CI = 11.1-20.71) in untreated patients (p = 0.021). As a consequence, if all patients underwent RAI treatment, the estimated risk of recurrence would be reduced by 42% (RR = 0.58; 95% CI = 0.35-0.91, p = 0.018). The greatest benefit was observed in patients with 2 intermediate risk factors. These results suggest that treatment with RAI in low to intermediate DTC can reduce the risk of recurrence in selected patients. However, definitive answers regarding whether to consider RAI therapy for this category of patients can only be attained through prospective clinical trials. Up to date these results recommend a meticulous assessment of tumor characteristics at diagnosis to guide the decision regarding RAI administration.

Decision Variables for the Use of Radioactive Iodine in Patients with Thyroid Cancer at Intermediate Risk of Recurrence.

The use of radioactive iodine (RAI) after total thyroidectomy for patients at the American Thyroid Association (ATA) who are at intermediate risk of recurrence is controversial. This is due to the lack of prospective randomized trials proving a benefit to recurrence or survival of RAI therapy in this group. In the absence of such evidence, clinicians struggle to recommend for or against this therapeutic approach which frequently results in overtreatment. This review describes key elements in the decision-making process that help clinicians more comprehensively evaluate the need for RAI therapy in patients with thyroid cancer at intermediate risk of recurrence. A clear definition of the purpose of RAI therapy should be conveyed to patients. In this sense, adjuvant RAI therapy intends to decrease recurrence, and ablation therapy is used to facilitate surveillance. Better stratification of the intermediate risk category into a low-intermediate subgroup and an intermediate-high-risk subgroup results in less heterogeneity and a more precise prediction of recurrence risk. The evaluation of post-operative thyroglobulin levels may prevent the overtreatment of low-intermediate-risk patients when their thyroglobulin level is <2.5 ng/mL. the integration of tumor genomics (when available) alongside pathologic features can enhance the ability of the clinician to predict iodine concentration in thyroid cancer cells. Finally, a detailed consideration of the adverse effects of RAI, patients' comorbidities, and patient preferences will result in a patient-centered personalized approach. Systematic examination of these variables will ultimately provide a framework for making more educated decisions on the use of RAI in patients at intermediate risk of recurrence that will prevent overtreatment and minimize harm.

Radioactive iodine ablation therapy reduces the risk of recurrent disease in pediatric differentiated thyroid carcinoma

BackgroundWhile radioactive iodine (RAI) therapy in older adults with differentiated thyroid carcinoma (DTC) reduces recurrence, data in pediatrics remain limited. We conducted a meta-analysis to quantify outcomes and recurrence risk with RAI versus thyroidectomy alone in the pediatric population. MethodsSystematic literature review identified 34 retrospective studies including 2913 DTC patients under age 22 years (published 2005–2023). Meta-analysis calculated pooled rates of disease persistence and recurrence. Relative risk ratios compared odds of recurrence with RAI versus no RAI. ResultsPatients had mean age 14.7 years (95 % CI, 14.2–15.2) and were 75.9 % female (95 % CI, 73.8–78.1 %). Majority (90.2 %) received RAI. Pooled persistence rate was 30.3 % (95 % CI, 21.7–39.5 %); higher with RAI (31.5 %; 95 % CI, 22.4–41.3 %) than no RAI (4.5 %; 95 % CI, 0.0–18.7 %) (OR 3.28; 95 % CI,1.82–5.91; p < 0.001). Recurrence rate was 8.97 % (95 % CI, 4.78–14.3 %). Those with RAI had 53.1 % lower recurrence risk versus no RAI (RR 0.47; 95 % CI, 0.27–0.82; p = 0.007). Median follow-up was 7.2 years (95 % CI, 5.8–8.5 years), with no association between follow-up duration and recurrence (r = −0.053; p = 0.80). ConclusionsRAI therapy as an adjunct to thyroidectomy is associated with a significantly lower risk of long-term recurrence in pediatric DTC. These findings advocate for the use of RAI in preventing recurrence among high-risk pediatric patients with DTC.

Implementation of the 2015 American Thyroid Association guideline changes across a health system: A quality improvement opportunity

BackgroundWith the release of the 2015 management guidelines, the American Thyroid Association narrowed the indications for postoperative radioactive iodine (RAI) in well-differentiated thyroid cancer. However, the adoption of new guidelines varies between healthcare entities. The goal of this study was to characterize the appropriateness of RAI use within our health system, before and after the 2015 guideline changes. MethodsIn this retrospective cohort study, we identified patients who were treated for well-differentiated thyroid cancer between 2011–2020. Patients were characterized as “undertreated,” “appropriately treated,” or “overtreated” with RAI. Variation in RAI use was assessed using interrupted time series and multivariable logistic regression analyses. ResultsAmong 6310 patients, the mean age was 50 ± 15 years, and 74% were female. There was an immediate drop in the likelihood of receiving RAI after the release of the 2015 guidelines (p = 0.016), and the likelihood of receiving RAI therapy continued to significantly decline over time (OR 0.83, p < 0.001). Despite this trend in the absolute rate of RAI use, there was a significant increase in overtreatment with RAI after the release of the 2015 guidelines (p < 0.001), indicating imperfect uptake of the new criteria. Two hospitals within the health system were identified as disproportionate contributors to overtreatment (Hospital 4: OR 6.50, p < 0.001; Hospital 6: OR 8.63, p < 0.001). ConclusionsWhile the use of postoperative RAI was largely appropriate across our health system, rates of guideline adherence differed between hospitals. Efforts to standardize treatment protocols systemwide may enable more rapid and consistent uptake of new management guidelines.

A 2023 International Survey of Clinical Practice Patterns in the Management of Graves' Disease: A Decade of Change.

Over the past several decades, there have been indications of potential shifts in the diagnostic strategies, treatment, and monitoring of patients with Graves´ disease (GD). To evaluate current practices in managing GD and compare them to previous surveys. We used a global survey of endocrinologists to assess diagnosis, monitoring and treatment in a typical patient with GD, as well as treatment variation in five different clinical scenarios. Online survey. Members of various endocrine societies worldwide. None. Shifts in the management of GD. 1252 respondents from 85 countries completed the survey. Methods used to diagnose an uncomplicated GD case have changed over the past decade, reflecting increased use of TRAb and reciprocal decreases in nuclear medicine studies. The preferred mode of therapy for uncomplicated GD was antithyroid drugs (ATDs) by 91.5% of respondents, radioactive iodine (RAI) therapy by 7%, and thyroidectomy by 1.5%. Compared with previous surveys, the use of RAI as a first-line choice decreased in all geographic regions. The U.S. had the sharpest decline in the selection of initial therapy with RAI, decreasing from 69% in 1990 to 11.1% in 2023. In patients with persistent TRAb positivity after 18 months, 68.7% of respondents would continue the use of ATDs. After a relapse of GD, resumption of ATDs was selected by 59.9% of respondents. In patients with active TED or planning pregnancy, ATDs were the first choice (67.5% and 72.8%, respectively), and thyroidectomy emerged as the second choice (22.9% and 15.6%, respectively). Paradigm shifts have occurred in the management of uncomplicated GD and its variants, as well as the response to persistent and recurrent hyperthyroidism.

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 with S values 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 and S values 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 Presence of Anti-TPO Antibodies Increase the Likelihood of Post-I131 Hypothyroidism.

The use of radioactive iodine in the treatment of hyperthyroidism is common practice. However, a standardized treatment protocol with regard to radioactive iodine treatment (RAI) remains subject to discussion. We retrospectively analyzed 100 patient records. Patient diagnosis, age, gender, body mass index (BMI), dose of radioactive iodine, thyroid size, the 24 h radioiodine uptake (24 h RAIU) and protein bound iodine (PBI) were deducted, as well as the use of antithyroid drugs prior to RAI. Biochemical parameters were obtained, such as TSH, fT4, fT3, Anti-TPO, Anti-TG antibodies and thyroid stimulating antibodies. After 5 years of follow-up, 46% of the patients proved to be hypothyroid, whereas 8% of the patients were not cured after one dose of RAI. One year after RAI, a larger proportion of patients with a toxic nodule developed hypothyroidism compared to patients with a multinodular goiter (MNG) (44.2% vs. 21.2%). Radioactive iodine dose, PBI, RAIU, BMI, size of the thyroid gland, diagnosis, age and TPO-antibodies showed statistically significant differences in the development of hypothyroidism. Furthermore, thiamazole pretherapy was shown to be a predictor of hypothyroidism, as well as a high PBI value, exhibiting a positive predictive value of 85.2% when the PBI exceeded 0.16. We suggest a standardized measurement of TPO-Ab's to further determine their role in the development of hypothyroidism after RAI. The empirical dosing regimen was very effective, illustrating a 92% cure rate after 1 dose.

Use of Radioactive Iodine in the Management of Thyroid Cancer in Those with Low-Clearance CKD/ESKD

Use of Radioactive Iodine in the Management of Thyroid Cancer in Those with Low-Clearance CKD/ESKD

Practice patterns in management of differentiated thyroid cancer since the 2014 British Thyroid Association (BTA) guidelines

BackgroundThe updated 2014 BTA guidelines emphasised a more conservative, risk adapted model for the management of low-risk differentiated thyroid cancer (DTC). In comparison to historical approach of total thyroidectomy combined with radioactive iodine, treatment de-escalation is increasingly supported. AimsTo evaluate the impact of the updated BTA guidelines on the management of DTC cases at regional UK centre. MethodsAll DTC patients were retrospectively identified from regional thyroid MDT database between Jan2009–Dec2020. Oncological treatment and clinico-pathological characteristics were analysed. Results623 DTC cases were identified; 312 (247 female: 65 male) between 2009 and 2014 and 311 (225 female: 86 male) between 2015 and 2020. Median age is 48 years (range 16–85). By comparing pre- and post-2015 cohorts, there was a significant drop in total thyroidectomy (87.1% vs 76.8%, p = 0.001) and the use of radioactive iodine (RAI) (73.1% vs 62.1%, p = 0.003) in our post-2015 cohort. When histological adverse features were analysed, extra-thyroidal extension (4.2% vs 17.0%, p=< 0.001), lymphovascular invasion (31.4% vs 50.5%, p=<0.001) and multi-centricity (26.9% vs 43.4%, p = 0.001) were significantly increased in the post 2015 cohort. Nonetheless, total thyroidectomy (TT) remains the treatment choice for low risk T1/2 N0 M0 disease in 65.3% (124/190) in post-2015 cohort for several reasons. Reasons include adverse histological features (50.8%), benign indications (32.5%), contralateral nodules (11.7%), patient preference (2.5%), and diagnostic uncertainty (2.5%). ConclusionOur study confirms a move towards a more conservative approach to patients with low-risk DTC in the UK, which is in keeping with the BTA 2014 guideline and international trends, but total thyroidectomy remains prevalent for low risk T1/2 N0 M0 disease for other reasons.

This house believes that: MARI/TAD is better than sentinel node biopsy after PST for cN+ patients.

The increasing use and effectiveness of primary systemic treatment (PST) enables tailored locoregional treatment. About one third of clinically node positive (cN+) breast cancer patients achieve pathologic complete response (pCR) of the axilla, with higher rates observed in Human Epidermal growth factor Receptor (HER)2-positive or triple negative (TN) breast cancer subtypes. Tailoring axillary treatment for patients with axillary pCR is necessary, as they are unlikely to benefit from axillary lymph node dissection (ALND), but may suffer complications and long-term morbidity such as lymphedema and impaired shoulder motion. By combining pre-PST and post-PST axillary staging techniques, ALND can be omitted in most cN+patients with pCR. Different post-PST staging techniques (MARI/TAD/SN) show low or ultra-low false negative rates for detection of residual disease. More importantly, trials using the MARI (Marking Axillary lymph nodes with Radioactive Iodine seeds) procedure or sentinel lymph node biopsy (SLNB) as axillary staging technique post-PST have already shown the safety of tailoring axillary treatment in patients with an excellent response. Tailored axillary treatment using the MARI procedure in stage I-III breast cancer resulted in 80% reduction of ALND and excellent five-year axillary recurrence free interval (aRFI) of 97%. Similar oncologic outcomes were seen for post-SLNB in stage I-II patients. The MARI technique requires only one invasive procedure pre-NST and a median of one node is removed post-PST, whereas for the SLNB and TAD techniques two to four nodes are removed. A disadvantage of the MARI technique is its use of radioactive iodine, which is subject to extensive regulations.

Disparities in Initial Thyroid Cancer Care by Hospital Treatment Volume: Analysis of 52,599 Cases in California.

Background: Racially minoritized patients with thyroid cancer are less likely to receive high-quality and guideline-concordant care. Inaccessibility of high-volume centers may contribute to inequalities in thyroid cancer outcomes. This study sought to understand the extent to which access to higher volume thyroid cancer centers is associated with patient outcomes. Methods: We queried linked California Cancer Registry and California Office of Statewide Health Planning and Development databases for thyroid cancer patients who received thyroid surgery between 1999 and 2017. Hospitals were stratified by their median annual volume of thyroid cancer operations: ultra-low volume (0-5 cases/year), low-volume (6-25 cases/year), mid-volume (26-50 cases/year), and high-volume (>50 cases/year). We analyzed the rates of complications, rates of reoperation for cancer recurrence, use of radioactive iodine (131I), and mortality by median hospital volume of thyroid surgery. A multivariable regression controlled for high-risk tumor features. Differences in access by center volume were assessed based on patient demographics. Results: We studied 52,599 thyroid cancer patients who underwent thyroidectomy. Patients who underwent thyroidectomy at ultra-low volume centers were more likely to undergo reoperations for recurrent/persistent disease compared with patients at low- (odds ratio [OR] 1.17 [CI 1.02-1.35]), mid- (OR 1.25 [CI 1.06-1.46]), and high-volume centers (OR 1.26 [CI 1.03-1.56]). Patients who received thyroid operations at ultra-low volume centers were also less likely to receive guideline-concordant 131I ablation compared with patients at higher volume centers (OR 0.77 [CI 0.72-0.82]). A pair-wise comparison between all volume categories for all outcomes revealed no statistically significant differences in outcomes between low-, mid-, or high-volume centers. Only ultra-low volume centers had significantly higher rates of adverse outcomes. Ultra-low volume centers were disproportionately accessed by women (p < 0.05), Hispanic, Asian/Pacific Islander, and American Indian people (p < 0.01), those from the lowest three quintiles of socio-economic status (p < 0.01), and the uninsured and those on Medicaid or Medicare (p < 0.01) when compared with higher volume centers. Conclusions: Patients receiving thyroid cancer surgery at centers performing ≤5 such operations per year were more likely to require reoperation for recurrent/persistent disease and less likely to receive appropriate 131I ablation. Ultra-low volume centers served higher proportions of socially and economically marginalized communities.

Characteristics, staging and outcomes of differentiated thyroid cancer in patients with and without Graves’ disease

BackgroundThe incidence of thyroid cancer has increased over the last three decades with studies showing incidence of thyroid cancer is higher among patients with Graves’ Disease (GD) when compared to Toxic multinodular goiter.1 We conducted a retrospective study to further investigate characteristics and outcomes in patients with thyroid cancer and GD. MethodsWe retrospectively reviewed 62 patients with a diagnosis of Differentiated Thyroid Cancer (DTC). We compared age at diagnosis, type, size of tumor, radioactive iodine (RAI) use, and DTC recurrence amongst patients with GD, non-GD patients. We used Chi-square to test for independence among categorical variables at a nominal level of 0.05; comparison was based on t-test. ResultsOut of 62 patients, 29 patients had GD and DTC (47%). 94% had papillary thyroid cancer. Patients with GD were diagnosed with DTC at a younger age (mean 46 years) in comparison to patients without GD (mean 53 years). There was no difference in the type of DTC. Patients with GD had significantly smaller tumor size (mean size 1.035 cm; p value = 0.002), more Stage 1 and 2 compared to patients without GD (p-value = 0.009). Both groups of patients had similar rates of recurrence on follow up and RAI use. ConclusionWe found patients with GD had smaller tumor size, early-stage DTC when compared to patients without GD and potentially favorable prognosis. More data is needed to understand whether this is due to pathogenesis like Graves antibodies promoting tumor formation or merely earlier detection of DTC in GD.

Trends in radioactive iodine treatment after total thyroidectomy in Italy, 2001-2018.

A decrease in the use of radioactive iodine (RAI) treatment for thyroid cancer has been described in the last decade in the US following subsequent updates of the American Thyroid Association guidelines. By contrast, population-based data from European countries are lacking. The study aims to assess the frequency and long-term trends in the use of RAI in Italy. From the Italian national hospital discharge database, the proportion of RAI treatment after total thyroidectomy with thyroid cancer diagnosis has been assessed by sex and age class during 2001-2018. Throughout the whole study period, RAI was performed after 58% of 149,419 total thyroidectomies. The use of RAI was higher for men and younger patients; it peaked in 2007 (64% in women and 68% in men) and declined thereafter (2018: 46% in women and 53% in men), with a similar pattern observed across all ages and areas. National data show that in Italy trends in RAI treatment paraleled those observed in the US. Further monitoring of the use of RAI is warranted in Italy, as elsewhere, to assess the impact of international guidelines on real-life clinical management of thyroid cancer.

Radioactive Iodine: A Living History

Background: Before the development of antithyroid drugs in the 1940s, treatment of Graves' hyperthyroidism was primarily surgical. Surgical mortality was quite variable, but a significant minority of patients died during or after surgery. Summary: In 1936, Karl Compton, President of the Massachusetts Institute of Technology, in a lecture attended by Massachusetts General Hospital physicians, suggested that artificially radioactive isotopes might be useful for studying metabolism. By 1942, Hertz and Roberts reported on the successful use of radioactive iodine (RAI) to treat Graves' hyperthyroidism. RAI uptake was subsequently demonstrated in well-differentiated thyroid cancer metastases. In 1948, Seidlin demonstrated stimulation of uptake in thyroid cancer metastases by thyrotropin (TSH). By 1990, 69% of endocrinologists in North America recommended RAI for Graves' hyperthyroidism. Currently RAI is less frequently used for Graves' hyperthyroidism, related to concerns about exacerbation of thyroid eye disease, about radiation exposure, and about potential adverse consequences of permanent hypothyroidism. Similarly, RAI was administered to the majority of patients with thyroid cancer for decades, but its use is now more selective. Conclusions: RAI is a remarkable example of interinstitutional cooperation between physicians and scientists to transition from bench to bedside in only three years. It is the model for a theranostic approach to disease (the simultaneous use of a radioactive drug for diagnosis and therapy). The future of RAI is less certain; inhibition of TSH receptor stimulating antibodies in Graves' disease and more precise targeting of genes that drive thyroid oncogenesis may diminish the use of RAI. Alternatively, redifferentiation techniques may improve the efficacy of RAI in RAI-refractory thyroid cancer.

The effect of radioactive iodine (RAI) on disease-specific survival in differentiated thyroid cancer (DTC): A study of 96,557 patients.

e18095 Background: The use of RAI in the treatment of DTC of various stages and risk levels is widespread. However, its efficacy continues to be a subject of debate, particularly with regard to low-risk patients. Some studies have found significant differences in RAI's ability to decrease recurrence and distant metastasis, while others have not. Thus, we conducted this study to evaluate the effect of RAI on disease-specific survival (DSS) in patients with DTC without distant metastasis. Methods: Data were obtained from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database between the years 2000 and 2018. Patients who have distant metastatic, tumor size ≥200 mm, receiving chemotherapy or any type of radiation other than RAI were excluded. Only patients with total thyroidectomy as surgical procedure were included. These patients were classified into three groups based on their histology: classical papillary thyroid carcinoma (C-PTC), follicular type variant carcinoma (FV-PTC), and follicular thyroid cancer (FTC). T-tests and chi-square tests were employed to compare variables, while the Cox proportional hazards model was utilized to assess the effect of RAI on DSS, presenting adjusted hazard ratios and confidence intervals. Results: The study population consisted of 96,557 patients, with 59,460 classified as having C-PTC, 31,583 as FV-PTC, and 5,489 as FTC. Most patients were female (78.6%), and the mean age was 45.8 years. 80.5% of the patients were white. The mean tumor size was 19.4 mm, with FTC tumors having a larger mean size of 34.8 mm. About a third of cases had an extrathyroidal extension. FV-PTC had the most favorable survival outcome with a 5-year DSS of 97.9%, followed by C-PTC (97.1%) and then FTC (96.9%). RAI was administered to 61.2% of FTC cases, 53.2% of C-PTC cases, and 52.1% of FV-PTC cases. In both FV-PTC and C-PTC, patients who received RAI had significantly better long-term survival than those who underwent surgery alone. The multivariable analysis confirmed that RAI had a more favorable prognosis in FV-PTC (HR = 0.68, 95%CI: 0.61 to 0.77, p&lt;0.001) and C-PTC (HR = 0.60, 95%CI: 0.54 to 0.67, p&lt;0.001), but did not result in improved DSS in FTC (HR = 0.87, 95%CI: 0.70 to 1.09, p = 0.226). There was a survival difference between the three histological subtypes in the overall cohort (p&lt;0.001), even after matching baseline characteristics (p = 0.019). Conclusions: Our results showed that RAI administration was statistically associated with improved long-term DSS outcomes in FV-PTC and C-PTC histological subtypes, but not in FTC. However, a careful interpretation of these results is needed as the survival benefit was less than 3% in all cohorts, it might be clinically insignificant. This study was the first to examine all histological types of DTC using a large sample size. There is a need for a randomized trial to confirm the efficacy of RAI in FTC treatment.

Absorbed dose coefficients for adult thyroid cancer patients undergoing radioiodine therapy

Use of radioactive iodine (RAI) for thyroid cancer patients is accompanied by elevated risks of radiation-induced adverse effects due to significant radiation exposure of normal tissues or organs other than the thyroid. The health risk estimation for thyroid cancer patients should thus be preceded by estimating normal tissue doses. Although organ dose estimation for a large cohort often relies on absorbed dose coefficients (i.e. absorbed dose per unit activity administered, mGy MBq−1) based on population models, no data are available for thyroid cancer patients. In the current study, we calculated absorbed dose coefficients specific for adult thyroid cancer patients undergoing RAI treatment after recombinant human TSH (rhTSH) administration or thyroid hormone withdrawal (THW). We first adjusted the transfer rates in the biokinetic model previously developed for THW patients for use in rhTSH patients. We then implemented the biokinetic models for thyroid cancer patients coupled with S values from the International Commission on Radiological Protection (ICRP) reference voxel phantoms to calculate absorbed dose coefficients. The biokinetic model for rhTSH patients predicted the extrathyroidal iodine decreasing noticeably faster than in the model for THW patients (calculated half-times of 12 and 15 h for rhTSH administration and THW, respectively). All dose coefficients for rhTSH patients were lower than those for THW patients with the ratio (rhTSH administration/THW) ranging from 0.60 to 0.95 (mean = 0.67). The ratio of the absorbed dose coefficients in the current study to the ICRP dose coefficients, which were derived from models for normal subjects, varied widely from 0.21 to 7.19, stressing the importance of using the dose coefficients for thyroid cancer patients. The results of this study will provide medical physicists and dosimetrists with scientific evidence to protect patients from excess exposure or to assess radiation-induced health risks caused by RAI treatment.