Postoperative Radioactive Iodine Therapy Research Articles

Long-term effect of postoperative radioactive iodine therapy on parathyroid function in patients with differentiated thyroid cancer.

The study aimed to assess the impact of postoperative radioactive iodine (RAI) therapy on parathyroid function in patients who underwent total or subtotal thyroidectomy for differentiated thyroid cancer (DTC). Data from 150 patients treated with RAI for DTC and 76 patients with low-risk DTC not receiving RAI were retrospectively analyzed. Clinical characteristics, preoperative and 1-month postoperative biochemical parameters, and adjusted calcium, phosphorus, parathyroid hormone (PTH), and 25-hydroxyvitamin D3 (25-OH-D) levels at 3months, 1year, 3years, and 5years post-RAI (or in the low-risk group) were recorded. A total of 226 DTC patients were included in the study (80.5% female, mean age 42.7 ± 13.2years). Total thyroidectomy was performed in 97.3% (n = 220) of patients, with central lymph node dissection (CLND) in 41.6% (n = 94). No significant preoperative differences in PTH, aCa, P, Mg, or 25-hydroxyvitamin D3 levels were observed. However, patients receiving ≥ 3.7GBq (or 100mCi) RAI (n = 70) had lower calcium and PTH levels at the end of the first year following RAI treatment (p = 0.048, p = 0.032). The non-RAI group showed significantly higher calcium levels at one month postoperatively (p = 0.031) and lower rates of CLND and neck dissection. No significant differences in biochemical parameters were found at the five-year follow-up, except for one patient who developed normocalcemic hyperparathyroidism after RAI. High-dose RAI therapy may lead to transient decreases in calcium and PTH levels in the early post-treatment period. However, long-term parathyroid function appears to remain unaffected in DTC patients, regardless of the RAI dose administered. Nonetheless, close monitoring of calcium and PTH levels is recommended, particularly in the early post-treatment period, to promptly manage any potential transient hypoparathyroidism.

Efficacy of postoperative radioactive iodine therapy for patients with low and intermediate risk papillary thyroid carcinoma.

This study aimed to evaluate the efficacy of postoperative radioactive iodine (RAI) and its impact on recurrence rates and survival benefits in low- to intermediate-risk papillary thyroid carcinoma (PTC). This retrospective study involved the examination of 1286 patients diagnosed with low- to intermediate-risk PTC who underwent total thyroidectomy with or without neck dissection, supplemented with postoperative RAI therapy or not between the years 2000 and 2021. From the patient pool, 589 (45%) were classified as low-risk and 697 (55%) as intermediate-risk according to the 2015 American Thyroid Association guidelines. Among the low-risk group, 375 (63.7%) underwent postoperative RAI, while in the intermediate-risk group, 566 (82.2%) underwent the procedure. The overall survival and disease-free survival rates were not statistically different between the groups that received RAI and those that did not, in both the low- and intermediate-risk categories. In a subgroup analysis, within the intermediate-risk category, postoperative RAI was significantly correlated with decreased recurrence in two subgroups: patients over 55 years with pN1b disease (hazard ratio 0.043, 95% confidence interval 0.004-0.500, p = 0.012) and patients over 55 years with five or more metastatic lymph nodes (hazard ratio 0.060, 95% confidence interval 0.005-0.675, p = 0.023). Our findings suggest that, while post-total thyroidectomy RAI does not substantially influence recurrence or survival rates in most low-risk and intermediate-risk PTC patients, it may be beneficial in specific subgroups, particularly patients over 55 with pN1b disease or those presenting with five or more metastatic lymph nodes.

Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma Is Related to a Poor Outcome: A Comparison Study Using Propensity Score Matching

ObjectiveThe clinical outcome of diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) remains controversial. We aimed to determine whether DSV-PTC is associated with an increased risk of persistent/recurrent disease. MethodsWe performed a retrospective cohort study of DSV-PTC and classic variant of papillary thyroid carcinoma (CV-PTC) after postoperative radioactive iodine therapy. We used propensity score matching (1:3 matching ratio) to account for differences between the recipients of DSV-PTC and CV-PTC. Univariate and multivariate analyses were performed to assess the independent factors for persistent/recurrent disease. The Kaplan-Meier curve analyses were used to compare disease-free survival (DFS). ResultsIn total, 35 (12.7%) patients with DSV-PTC and 240 (87.3%) patients with CV-PTC were included. After propensity score matching, 35 pairs of patients were selected (DSV-PTC, n = 35; CV-PTC, n = 105). In the matched analysis, a higher proportion of patients with DSV-PTC experienced persistent/recurrent disease than that of those with CV-PTC (25.7% vs 5.7%, P = .003). In the multivariate analyses of clinical and tumor characteristics, only the histologic type of DSV-PTC (odds ratio, 6.288; 95% confidence interval, 1.900-20.811; P = .003) was associated with an increased risk of persistent/recurrent disease. The 5-year DFS rates for the DSV-PTC and CV-PTC groups were 69.2% and 93.6%, respectively. The Kaplan-Meier analysis indicated that the DSV-PTC group (P= .001) had shorter DFS. ConclusionThis propensity score–matched analysis found that the histologic type of DSV-PTC may increase the risk of persistent/recurrent disease.

Differentiated thyroid carcinoma recurrence: patterns and participating factors

Background Surgery for recurrent differentiated thyroid carcinoma is technically difficult, is demanding, and carries a higher risk for complications than de novo cases, so understanding the precipitating factors and patterns of recurrence will help in practicing maneuvers that can help in decreasing the recurrence. In this study, we examined these factors and patterns of recurrence. Patients and method A total of 40 patients with recurrence after differentiated thyroid carcinoma surgery were subjected to redooperations after clinical evaluation and all needed preoperative investigations. Preoperative and operative data and postoperative surgical and pathological outcomes were collected and analyzed. Results Our results revealed that the size of the primary tumor had a negative or inverse significant relationship with time passed till occurrence of recurrence or relapse (P=0.044). However, postoperative radioactive iodine therapy, postoperative thyroxine replacement therapy, unifocal tumors, and total thyroidectomy in primary procedure all were associated with a wider range of recurrence time with a higher mean±SD but did not reach a statistically significant level. Central compartment lymph nodes are the most affected group (95%) followed by level IV nodes, which had a 100% correlation with central group, and all lateral groups summed 82.5%. Conclusion The primary tumor size has a significant inverse relationship with time till occurrence of relapse. However, other factors did not reach a statistically significant level. Central compartment lymph nodes, which are very difficult for safe dissection in recurrent cases, are the most affected group, confirming being the first echelon nodes followed by level IV nodes. Therefore, prophylactic routine meticulous central dissection in the primary cases is advised for being much easier and safer.

Molecular-genetic testing in preoperative diagnosis and choice of surgical tactics in patients with thyroid neoplasms

The high frequency of the detection of follicular thyroid tumors requires the development of the most effective new methods for their differential diagnosis to early verification of well-differentiated cancer, reduce the number of unjustified surgical interventions, select their rational volume, and improve the treatment results. The use of molecular genetic research methods in preoperative diagnostics and the choice of surgical tactics in patients with the thyroid neoplasms was substantiated. To optimize the algorithm of diagnosis and treatment, a retrospective analysis of the results of examination and surgical treatment of 100 patients with the thyroid neoplasms was carried out, the diagnosis of which was supplemented by the determination of molecular genetic markers in the cellular material of the puncture fine-needle biopsy using a flow fluor-cytometry and polymerase chain reaction. The diagnostic significance of the preoperative determination of the tumor marker Galectin-3, the V600E mutation of the BRAF gene in the puncture material in the detection of thyroid cancer and the choice of the rational surgical tactics was assessed. The prognostic value of the sodium iodide symporter in the development of a thyroid cancer resistance to postoperative radioactive iodine therapy has been established, which makes it possible to substantiate the need to expand the scope of the surgical intervention. The use of an optimized diagnostic and treatment algorithm, considering a new molecular genetic research methods in this category of the patients, contributes to the choice of individualized surgical tactics, depending on the nature of the pathological process.

Transoral Endoscopic Thyroidectomy by Vestibular Approach for Differentiated Thyroid Cancer Intraoperatively Invading Strap Muscle.

Transoral endoscopic thyroidectomy vestibular approach (TOETVA) has become increasingly popular in the surgical treatment of thyroid cancer. However, its application in T3b disease has not been well-defined. We conducted a quasi-experimental study on patients with an intraoperative diagnosis of T3bN0M0 differentiated thyroid carcinoma from January 2019 to January 2021 in our institution. Surgical and early oncological outcomes were assessed. Among 326 patients who underwent TOETVA for thyroid cancer, 12 cases had T3bN0M0 disease intraoperatively. The mean operation time was 136.67±7.32 minutes, with 7.17±0.83 mL of blood loss. No patients reported symptoms of postoperatively transient hypoparathyroidism, mental nerve, or recurrent laryngeal nerve injury. After radioactive iodine therapy, all patients had undetectable thyroglobulin, negative antithyroglobulin, and normal neck ultrasound. TOETVA seems to be a surgically and oncological safe method for differentiated thyroid cancer patients with small tumors invading strap muscle intraoperatively. The patients can be well-managed with endoscopic total thyroidectomy and postoperative radioactive iodine therapy. Further studies with a larger sample size and longer follow-up are needed to provide more solid evidence.

Caracterización de pacientes con microcarcinoma papilar de tiroides en el Hospital de Clínicas (UDELAR) en los últimos 10 años

Introduction: papillary thyroid microcarcima (PTMC) is a tumour <1 cm in size, indolent and with incidental or asymptomatic diagnostic. Recently, the incidence of PTMC increased as a result of higher ultrasound detection of nonpalpable nodes, although mortality rates remain stable, with high survival in the long-term.Objective: to characterize patients with PTMC at the Endocrinology and Metabolism Department of the Clinicas University Hospital in the 2008-2018 decade.Method: observational, transversal, retrospective and analytical study. Medical records filed and policlinic records of patients who were seen in our service since June, 2008 and June, 2018 were reviewed. The number of patients assisted in the hospital between 1978 and 2008 was found, to estimate incidence and annual casuistic. Statistical analysis of variables and tendencies was performed.Results: 42 (22%) out of 139 patients with poorly differentiated thyroid carcinoma (PDTC) had papillary thyroid microcarcinoma. In the last 40 years, hospital incidence of PTMC has increased (average = 4,2 cases/year), 88% of which were female patients. 69% of diagnostics were done by thyroid fine-needle aspirate cytology (FNAC); 57% were single focal and 43% multifocal. There was a significant association between multifocality and capsule invasion. 84% of cases did not evidence lymph node metastases. In 55% of cases postoperative radioactive iodine therapy was applied.Conclusions: the incidence of PTMC increased, mainly in women. Diagnosis prior to surgery was mainly done by thyroid FNAC. Capsular invasion was associated to multifocality. 16% evidence lymph node metastases upon diagnosis. Complete thyroidectomy was done in most cases, followed by radioactive iodine therapy un 55% of cases.

Is Postoperative Adjuvant Radioactive Iodine Ablation Therapy Always Necessary for Intermediate-Risk Papillary Thyroid Cancer Patients With Central Neck Metastasis?

Papillary thyroid cancer (PTC) is commonly associated with neck lymph node metastasis (LNM), and recurrence does occur after radioactive iodine (RAI) ablation therapy. This study aimed to analyze the effectiveness of RAI ablation with regard to disease recurrence in intermediate-risk PTC patients with neck LNM. In addition, the study identified possible predisposing risk factors that might benefit from RAI ablation and analyzed common RAI therapy complications among these patients. A retrospective analysis of 349 intermediate-risk PTC patients with neck LNM who underwent thyroidectomy with neck dissection was performed. The oncologic results and clinicopathologic characteristics of these patients together with the incidence of postoperative RAI therapy complications were evaluated. Of the 349 patients, disease recurrence after treatment occurred for 27 patients (8%) during a mean follow-up period of 58.7 months (range 7-133 months). The recurrence-free survival curve of the patients who received postoperative RAI therapy (n = 208) did not differ significantly from that of the patients who did not receive it (n = 141) (P = 0.567). Nine patients without adjuvant RAI therapy (6%, 9/141) had recurrence. The recurrence rate for the central LNM patients without RAI therapy was only 2% (2/106). Both of these patients with recurrence had pathologic extranodal spread (ENS) and a high number (> 5) of metastatic central LNs. Postoperative RAI-related complications were observed in 24 patients (12%). Postoperative RAI is not necessary for intermediate-risk papillary thyroid cancer patients with central LNM, especially for patients with negative ENS and low number (< 5) of metastatic lymph nodes.

Does the radioactive iodine dose affect smell, taste sensation and nose function?

To detect whether the adverse effects of post-operative radioactive iodine therapy following differentiated thyroid cancer on smell, taste and nasal functions were associated with radioactive iodine dose. Fifty-one patients who had undergone total thyroidectomy because of differentiated thyroid cancer were divided into two groups depending on the post-operative radioactive iodine therapy dose: low dose group (50 mCi; 21 patients) and high dose group (100-150 mCi; 30 patients). The Sniffin' Sticks smell test, the Taste Strips test and the 22-item Sino-Nasal Outcome Test were performed on all patients one week before therapy, and at two months and one year following therapy. Statistically significant differences were detected in the Sniffin' Sticks test results, total odour scores, total taste scores and Sino-Nasal Outcome Test results between the assessment time points. There was no statistically significant difference between the low and high dose groups in terms of odour, taste or Sino-Nasal Outcome Test scores either before or after therapy. Radioactive iodine therapy has some short- and long-term adverse effects on nasal functions and taste and odour sensations, which affect quality of life. These effects are not dose-dependent.

Clinical Outcomes of N1b Papillary Thyroid Cancer Patients Treated with Two Different Doses of Radioiodine Ablation Therapy.

BackgroundThe optimal dose of radioactive iodine (RAI) therapy for N1b papillary thyroid carcinoma (PTC) is controversial. We evaluated the clinical outcome of N1b PTC patients treated with either 100 or 150 mCi of RAI.MethodsWe retrospectively analyzed N1b PTC patients who underwent total thyroidectomy and postoperative RAI therapy at a tertiary referral center between 2012 and 2017. As the baseline characteristics differed between treatment groups, we performed exact matching for various pathological factors according to RAI dose. We evaluated the response to therapy and recurrence-free survival (RFS) in the matched patients. Structural recurrent/persistent disease was defined as new structural disease detected after initial therapy, which was confirmed by cytology or pathology.ResultsOf the total 436 patients, 37 (8.5%) received 100 mCi of RAI and 399 (91.5%) received 150 mCi of RAI. After an exact 1:3 matching, 34 patients in the 100 mCi group and 100 patients in the 150 mCi group remained. There was no significant difference in response to therapy between the groups in the matched population (P=0.63). An excellent response was achieved in 70.6% (n=24) of patients in the 100 mCi group and 76.0% (n=76) in the 150 mCi group. Two (5.9%) patients in the 100 mCi group and four (4.0%) in the 150 mCi group had recurrence and there was no significant difference in RFS between the groups in the matched population (P=0.351).ConclusionThere were no differences in response to therapy and RFS in N1b PTC patients according to RAI dose.

Combined role of lymph node ratio and serum thyroglobulin levels in predicting prognosis of papillary thyroid carcinoma.

The aim of this study was to evaluate a prognostic value of the extent of metastatic lymph node combined with TSH-stimulated serum thyroglobulin (sTg) measured just before radioactive iodine (RAI) therapy in patients with papillary thyroid cancer (PTC). The retrospective study included 468 patients with PTC who underwent total thyroidectomy with neck dissection and postoperative RAI therapy. The extent of metastatic lymph node was evaluated with the lymph node ratio (LNR) which was defined as the number of metastatic lymph nodes out of the number of total removed lymph nodes. We investigated which factors could significantly predict persistent or recurrent disease (PRD). LNR ≥0.4 (P = 0.002) and sTg ≥6.0 ng/mL (P < 0.001) were associated with PRD in univariate analysis. In multivariate analysis, only male [hazard ratio: 2.35, 95% confidence interval (CI): 1.18-4.66, P = 0.014] and sTg (hazard ratio: 9.35, 95% CI: 4.44-19.67, P < 0.001) were associated with PRD prediction. When we divided patients into two groups (patients with sTg level < 6.0 ng/mL and those with sTg level ≥ 6.0 ng/mL), LNR (≥0.4) was a significant predictor of PRD in patients with sTg <6.0 ng/mL (hazard ratio: 4.38, 95% CI: 1.22-15.72, P = 0.024). LNR ≥0.4 was a significant predictor of PRD when the sTg level was <6.0 ng/mL. LNR should be used in combination with a relatively low level of serum sTg to predict the prognosis of patients with PTC.

Size of the Largest Metastatic Focus to the Lymph Node is Associated with Incomplete Response of Pn1 Papillary Thyroid Carcinoma

Objective: To evaluate the influence of the size of the metastatic focus in lymph nodes (LNs) on therapeutic response among papillary thyroid cancer (PTC) and cervical pathologically proven LN metastases (pN1). Methods: Patients with pN1 PTC who underwent total or near-total thyroidectomy, LN dissection, and postoperative radioactive iodine therapy in a university hospital between 2014 and 2016 were retrospectively reviewed. Furthermore, 554 patients were assigned to three groups according to the size of the metastatic focus in the LNs (≤0.2 cm, 0.2 to 1.0 cm, ≥1.0 cm). Structural incomplete response (SIR) was defined as structural or functional evidence of disease with any thyroglobulin level and/or anti-thyroglobulin antibodies. Results: Among the 554 patients, the proportion of patients with SIR was 2.5% (4/161) in group 1, 13.9% (37/267) in group 2, and 46.8% (59/126) in group 3 (χ2 = 100.073; P<.001). The optimal cutoff value of the size of the largest metastatic focus to the LNs was 0.536 cm to predict SIR with a corresponding sensitivity of 0.82, a specificity of 0.716, and an area under the curve of 0.821 (95% confidence interval [CI], 0.777 to 0.864; P<.001). Size of the largest metastatic focus to the LNs was confirmed to be an independent predictive factor for SIR (odds ratio, 9.650; 95% CI, 4.925 to 18.909; P<.001). Conclusion: In patients with pN1 PTC, there is an association between the size of the largest metastatic focus to the LNs and incomplete response. Abbreviations: AJCC = American Joint Committee on Cancer; ATA = American Thyroid Association; BIR = biochemical incomplete response; CI = confidence interval; ER = excellent response; ETE = extranodal extension; 18F-FDG = 18F-fluorodeoxyglucose; IDR = indeterminate response; LN = lymph node; OR = odds ratio; PET/CT = positron emission tomography/computed tomography; pN1 = pathologically proven LN metastases; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; ROC = receiver operating characteristic; SIR = structural incomplete response; sTg = stimulated thyroglobulin; TgAb = anti-thyroglobulin antibody; TSH = thyroid-stimulating hormone.

The BRAFV600E mutation in papillary thyroid microcarcinoma with intermediate-risk to high-risk features: does the mutation have an effect on clinical response to radioiodine therapy?

ObjectivesPreclinical studies showed that BRAFV600E mutation significantly reduced radioiodine uptake and decreased the sensitivity to radioactive iodine (RAI) therapy. However, clinical data regarding its role in therapeutic decision making with respect to RAI therapy are currently insufficient. Thus, this study aimed to evaluate the effect of BRAF mutation on the clinical response to RAI therapy for papillary thyroid microcarcinoma (PTMC) with intermediate-risk to high-risk features.Patients and methodsFrom January 2012 and October 2015, consecutive patients with PTMC with intermediate-risk to high-risk features who underwent RAI therapy were retrospectively included. The data about BRAF mutation status were also obtained. The association between clinicopathological characteristics and mutation was investigated. After a median follow-up of 40 months, the clinical response to RAI therapy was also compared between positive and negative mutation groups.ResultsA total of 236 patients were included, of whom 147 (62.3%) had positive mutation. The clinicopathological features did not show significant correlation with BRAF mutation status except the sex, extrathytoidal extension and T stage. Patients with PTMC with BRAF mutation showed an increased likelihood of having advanced T stage and extrathyroidal extension. In addition, this mutation did not affect the clinical outcome of RAI therapy.ConclusionThe status of BRAFV600E mutation may not affect the clinical response to RAI therapy for patients with PTMC with intermediate-risk to high-risk features. More trials examining the role of BRAF mutation in guiding postoperative RAI therapy are needed.

A 'silent' skull metastatic follicular thyroid carcinoma mimicking as a benign scalp tumor in a pregnant woman.

SummaryThyroid cancer with cranial metastasis in a pregnant woman is very rare. In the literature, most cases are diagnosed early from neurogenic signs or symptomatic thyroid gland. Pregnancy also contributes to a hesitation toward early surgical and medical treatments. We reported a scalp tumor in a physically healthy 37-year-old pregnant female with a follicular thyroid carcinoma (FTC) with lung, bone and cranial metastasis in initial presentation. Silent neurogenic and physical examinations make an early diagnosis very challenging. Resection of scalp and intracranial tumor, a thyroidectomy, post-operative radioactive iodine therapy and tyrosine kinase inhibitors were employed as treatment. The scalp tumor was confirmed as a metastatic follicular thyroid carcinoma via positive immunoreactivity for thyroglobulin and thyroid transcription factor 1 in tumor cells. Blood examination revealed an elevated thyroglobulin level (>5335 ng/mL). The patient was discharged without any neurological deficit. An asymptomatic scalp tumor in a pregnant woman with a normal thyroid disease history needs differential diagnosis from intracranial origin. Rapid progression and an elevated thyroglobulin level are the indicators that further image study is needed. Aggressive surgical excision of resectable thyroid gland and metastatic tumor are essential for a longer survival rate. There is nothing to indicate that a post-partum operation will worsen prognosis.Learning points:Follicular thyroid cancer with cranial metastasis in initial presentation can be asymptomatic.Follicular thyroid cancer with cranial metastasis in a pregnant woman can be treated after delivery.Rapid enlargement of scalp tumor is indicated for further image study even in a patient without any neurological deficit.

Lymph node characteristics for predicting locoregional recurrence of papillary thyroid cancer in adolescents and young adults

PurposeTo determine lymph node (LN) characteristics predictive of locoregional recurrence (LRR) in adolescent and young adult (AYA) ages 15–39years presenting with papillary thyroid cancer (PTC) and cervical pathologically proven LN metastases (pN1). Methods and materialsRetrospective chart review was performed for all patients with PTC and nodal metastases who had undergone total thyroidectomy, LN dissection, and postoperative radioactive iodine therapy in a university hospital between 2006 and 2014. Clinical and histopathologic markers that were independently associated with tumor recurrence were evaluated. ResultsIn all, 329 consecutive AYA patients were included. At a median follow-up of 57months, twenty patients (6.08%) experienced LRR. No patients had distant metastases, and no patients died during follow-up. Based on Cox regression analysis, the presence of extranodal extension and more than six metastatic LNs at presentation were independent predictive factors for LRR. However, age, male sex, total number of LNs resected, pN1b, LN ratio, size of the largest metastatic LN, extrathyroidal extension, tumor size, bilateral tumor, multifocality, vascular invasion, and Hashimoto thyroiditis were not correlated with an increased risk for LRR. A cutoff of more than six positive nodes optimally predicted future LRR with sensitivity and specificity values of 85.0% and 60.2%, respectively. ConclusionThe presence of extranodal extension and more than six metastatic LNs were independent predictors of LRR in AYA patients with pN1 disease. Evaluation of these prognostic factors appears to help identify patients who require close monitoring.

Clinical Features and Outcomes of Papillary Thyroid Carcinoma in Patients Aged under 20

Received June 9, 2015 Revised July 16, 2015 Accepted July 17, 2015 Address for correspondence Ik Joon Choi, MD Department of OtorhinolaryngologyHead and Neck Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul 01812, Korea Tel +82-2-970-1271 Fax +82-2-970-2450 E-mail medica95@hanmail.net Background and ObjectivesZZThyroid carcinoma rarely occurs in children and adolescents, whose clinical features are diverse, and treatment outcomes are still controversial. The aim of this study was to evaluate the clinical features and the treatment outcomes of papillary thyroid carcinoma (PTC) patients younger than 20 years old. Subjects and MethodZZThis is a retrospective study for patients younger than 20 years old, who were diagnosed as PTC from January 1992 to February 2009. Clinical features, size, pathologic type, extrathyroidal extension, recurrence, multiplicity, extent of surgery, and lymph node metastasis were retrospectively evaluated. ResultsZZForty patients, of 6 malse and 34 females, were enrolled, with their mean age being 16 years old. The initial operations were total thyroidectomy for 9 patients, unilateral lobectomy for 15 patients, and total thyroidectomy and lateral neck dissection for 16 patients. Cervical lymph node metastases were diagnosed in 25 patients. Extrathyroidal extensions were observed in 30 patients. Postoperative radioactive iodine therapy was performed in 35 patients. During the follow-up period, 8 patients had recurred. All patients were alive at the last follow-up. ConclusionZZPTC in children and adolescents aged under 20 is a rare disease and tends to present as an advanced disease with low mortality compared to adult PTC. Recurrence had no effect on survival. Aggressive treatment with total thyroidectomy, central neck dissection, and radioiodine therapy may prevent recurrence. Korean J Otorhinolaryngol-Head Neck Surg 2015;58(11):764-8

Current controversies in the initial post-surgical radioactive iodine therapy for thyroid cancer: a narrative review.

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy and the fifth most common cancer in women. DTC therapy requires a multimodal approach, including surgery, which is beyond the scope of this paper. However, for over 50 years, the post-operative management of the DTC post-thyroidectomy patient has included radioactive iodine (RAI) ablation and/or therapy. Before 2000, a typical RAI post-operative dose recommendation was 100 mCi for remnant ablation, 150 mCi for locoregional nodal disease, and 175-200 mCi for distant metastases. Recent recommendations have been made to decrease the dose in order to limit the perceived adverse effects of RAI including salivary gland dysfunction and inducing secondary primary malignancies. A significant controversy has thus arisen regarding the use of RAI, particularly in the management of the low-risk DTC patient. This debate includes the definition of the low-risk patient, RAI dose selection, and whether or not RAI is needed in all patients. To allow the reader to form an opinion regarding post-operative RAI therapy in DTC, a literature review of the risks and benefits is presented.

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

BackgroundDue 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.MethodsWe 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.ResultsA 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.ConclusionOur 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

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

Thyroid Cancer Outcomes in Filipino Patients

To compare the outcomes of patients having thyroid cancer among Filipinos vs non-Filipinos. Retrospective medical record review. High-volume tertiary referral center in Toronto, Ontario, Canada. A total of 499 patients with thyroid cancer (36 Filipino and 463 non-Filipino) treated at Mount Sinai Hospital from January 1, 1984, to August 31, 2003, with a minimum 5-year follow-up period and a minimum 1.0-cm tumor size. Patients were identified from a thyroid cancer database. Data on patient, tumor, and treatment factors were collected along with outcomes. The presence of thyroid cancer recurrence, the rate of death from disease, and the time to recurrence. The 2 groups were similar for sex, age, history of head and neck radiation exposure, family history of thyroid cancer, follow-up time, tumor size, tumor pathologic findings, presence of tumor multifocality, stage of primary disease, type of thyroid surgery, use of postoperative radioactive iodine therapy, and use of external beam radiation therapy. Filipino patients experienced a thyroid cancer recurrence rate of 25% compared with 9.5% for non-Filipino patients (odds ratio, 3.20; 95% confidence interval, 1.23-7.49; P = .004). On multivariate analysis, the increased risk of thyroid cancer recurrence persisted for Filipino patients (odds ratio, 6.99; 95% confidence interval, 2.31-21.07; P < .001). No significant differences were noted between Filipino patients and non-Filipino patients regarding the rate of death from disease (5.6% vs 1.9%) and the time to recurrence (52.6 vs 53.1 months). Filipino patients have a significantly higher risk of thyroid cancer recurrence compared with non-Filipino patients. However, no significant difference was noted in the time to recurrence or the rate of death from disease. These findings justify a more aggressive initial management and follow-up regimen for Filipino patients with thyroid cancer.