Radioactive Iodine Remnant Research Articles

Controversial Issues in Thyroid Cancer Management.

The lack of prospective randomized clinical trials for most management topics in differentiated thyroid cancer forces us to make management recommendations based on retrospective observational data, which are often incomplete, subject to selection bias, and conflicting. Therefore, it is not surprising that many aspects of thyroid cancer management remain controversial and not well defined. This review will examine the controversies surrounding 3 important topics in thyroid cancer management: the option of thyroid lobectomy as initial therapy, the use of preoperative neck imaging to optimize the completeness of the initial surgery, and the selective use of radioactive iodine for remnant ablation, adjuvant treatment, or treatment for known persistent or recurrent disease. As thyroid cancer management moves toward a much more risk-adapted approach to personalized recommendations, clinicians and patients must balance the risks and benefits of the potential options to arrive at a plan that is optimized regarding both patient preferences/values and the philosophy/experience of the local disease management team.

Postsurgical Outcomes and Surgical Completeness of Robotic Thyroid Surgery: A Single Surgeon's Experience on 700 Cases.

Advanced technology and understanding of robotic surgical system have rendered robotic thyroid surgery more expanding. The aim of this study was to identify the periodic changes in postsurgical outcomes of robotic thyroid surgery performed by a single surgeon. We conducted a retrospective review of 700 robotic thyroid surgery cases using gasless trans-axillary approach. All patients underwent successful operations without conversion to open surgery, and were mostly younger than 45 years, female, less-extended thyroid surgery and lymph node dissection, and thyroid cancer. The median follow-up period was 67 months (12-99 months). Regarding technical outcomes, the operation time declined steeply after 100 consecutive cases, and reached 120.0-132.7 minutes for thyroid lobectomy and 162.9-174.1 minutes for total thyroidectomy (TT). The most common complication was transient hypoparathyroidism (43.7%), whose incidence decreased steeply to a range of 9.1% to 25.0% after 300 consecutive cases. Regarding surgical completeness for thyroid cancer, an average of seven lymph nodes was retrieved through central compartment node dissection without fluctuation over time. The proportion of the patients with serum stimulated thyroglobulin levels <10 ng/mL at the time of radioactive iodine remnant ablation after TT and <1 ng/mL 6-12 months after the first remnant ablation ranged between 86.4%-100% and 66.7%-100%, respectively, without significant fluctuation. For properly selected patients, robotic thyroid surgery is useful surgical option with reliable technical outcome and surgical completeness and cosmetic benefit.

A Follow-Up Strategy for Patients with an Excellent Response to Initial Therapy for Differentiated Thyroid Carcinoma: Less Is Better.

The risk of recurrence in patients with differentiated thyroid cancer (DTC) can be estimated based on their response to initial therapy. The aim of this study was to evaluate an adequate follow-up strategy for DTC patients with an excellent response by assessing the characteristics of structural recurrence. This historical cohort study included 1359 DTC patients who had excellent response to total thyroidectomy with radioactive iodine remnant ablation. Among 1359 patients, 703 (54%) patients were classified as stage I according to the seventh tumor node metastasis staging system, and 987 (73%) patients were classified as intermediate risk according to the American Thyroid Association's risk stratification after initial therapy. During a median of 8.7 years of follow-up, only 13 (1%) patients were confirmed to have structural recurrence. All of the recurrences were locoregional disease, and there were no distant metastases. Recurrences were detected late at a median of 5.5 years after the initial surgery (range 3.6-10.7 years). All structural recurrences were detected on neck ultrasonography. Non-stimulated serum thyroglobulin (Tg) was detectable (≥0.2 ng/mL) in four (31%) patients, and serum anti-Tg antibodies were positive in one (8%) patient. However, non-stimulated serum Tg levels were stably low (<0.2 ng/mL) in eight (62%) patients when recurrences were detected. In addition to these 13 patients, 14 patients also presented with biochemical persistent disease at the end of follow-up. Recurrences of DTC in patients with an excellent response to initial therapy were detected relatively late. The intensity and frequency of follow-up of neck ultrasonography as well as serum Tg and anti-Tg antibody measurements should be reduced, especially within five years of the initial therapy, in DTC patients who have an excellent response.

Controversies in the Management of Low-Risk Differentiated Thyroid Cancer.

Controversy exists over optimal management of low-risk differentiated thyroid cancer. This controversy occurs in all aspects of management, including surgery, use of radioactive iodine for remnant ablation, thyroid hormone supplementation, and long-term surveillance. Limited and conflicting data, treatment paradigm shifts, and differences in physician perceptions contribute to the controversy. This lack of physician consensus results in wide variation in patient care, with some patients at risk for over- or undertreatment. To reduce patient harm and unnecessary worry, there is a need to design and implement studies to address current knowledge gaps.

Dynamic risk stratification for predicting recurrence in patients with differentiated thyroid cancer treated without radioactive iodine remnant ablation therapy

Background: Increased incidence of small differentiated thyroid cancer (DTC) has emphasized the need for risk stratification and individualized disease management for these low risk DTCs. The aim of this study was to validate a new dynamic risk stratification (DRS) system for the prediction of structural recurrent/persistent disease in patients with DTC treated without radioactive iodine (RAI) remnant ablation therapy. Methods: This historical cohort study included 357 patients with DTC treated with lobectomy or total thyroidectomy without RAI therapy. We stratified patient response to initial treatment as excellent, indeterminate, biochemical incomplete, and structural incomplete according to the DRS system. Results: During a median follow-up of 8.6 years, 3.6% patients had structural recurrent DTC. The response was excellent in 71.7% patients, indeterminate in 18.5%, biochemical incomplete in 8.4%, and structural incomplete in 1.4%. There were significant differences in DFS among the DRS groups (p < 0.0...

The need of prophylactic central lymph node dissection is controversial in terms of postoperative thyroglobulin follow-up of patients with cN0 papillary thyroid cancer.

The objective of this study was to investigate whether prophylactic central lymph node dissection (pCLND) facilitates postoperative thyroglobulin (Tg) follow-up in the patients with papillary thyroid carcinoma (PTC). We also questioned whether radioactive iodine (RAI) remnant ablation provides any further advantage in this regard. The records of patients with low-intermediate risk PTC who underwent either only total thyroidectomy (TT) or TT in conjunction with pCLND were reviewed. Adjuvant RAI ablation was performed depending on tumor diameter, multifocality, the presence of positive lymph nodes and adverse histopathologic features. Pre-ablative and post-ablative Tg levels, post-operative complications and clinico-pathological characteristics were compared between the two groups (TT alone and TT with pCLND). Among the 302 patients, TT was performed in 140 (46.4%) and TT with pCLND in 162 (53.6%). More than half of all patients in both groups had papillary microcarcinoma (58.0% and 53,1%, respectively). Postoperatively, the median preablative Tg level was higher in the TT only group than that of the TT with pCLND group (0.96 vs 0.27ng/ml, respectively). The post-ablative Tg levels were undetectable in both groups at the last follow-up visit. Also, a subgroup of patients (19.5%) who did not receive RAI ablation all became athyroglobulinemic at one year after surgery. Although performing pCLND with TT seems to have an advantage over TT alone as to achieve lower Tg levels in the early post-operative period, Tg levels become comparable following RAI ablation. On the other hand, the patients who have not been treated with adjuvant RAI ablation, also became athyroglobulinemic regardless of the surgical method.

Dynamic Risk Estimates of Outcome in Chinese Patients with Well-Differentiated Thyroid Cancer After Total Thyroidectomy and Radioactive Iodine Remnant Ablation.

This study was conducted to compare the staging systems for the prediction of long-term disease status in patients with well-differentiated thyroid carcinoma (WDTC), and to find out the earliest postoperative period predictor of long-term persistence/recurrence of disease. Patients with WDTC (n = 356; Mage = 41.5 ± 12.7 years) followed for at least five years (12.3 ± 5.0 years) after thyroidectomy and 131I remnant ablation at a tertiary regional hospital in Taiwan were retrospectively studied. Each patient was risk stratified using the American Joint Cancer Committee (stage I-IV) and American Thyroid Association (low, intermediate, and high risk) staging systems after operation and first 131I remnant ablation and using response to initial therapy reclassification (RTR; excellent, indeterminate, biochemical incomplete, and structural incomplete response) system, which is determined 6-24 months after the first 131I ablation. The clinical outcome was defined as no evidence of disease (NED; suppressed thyroglobulin [Tg] <0.5 ng/mL, stimulated Tg <1 ng/mL, and no structural detectable disease), biochemical persistent disease (BPD; suppressed Tg ≥0.5 ng/mL or stimulated Tg ≥1 ng/mL in the absence of structural disease), structural persistent disease (SPD; locoregional or distant metastases with any Tg level), or recurrent disease (RD; biochemical or structural disease identified after a period of NED). At the time of final follow-up, 78.4% (n = 279) of the patients had NED, 9.3% (n = 33) had BPD, 10.1% (n = 36) had SPD, and 2.2% (n = 8) developed RD. All three systems could predict the increasing trend of SPD and the decreasing trend of NED with advancing stage of disease. However, the ATA risk estimates could be significantly refined by the RTR system, especially for the ATA high-risk group, in which 29.2% developed SPD/RD during follow-up. The RTR system reduced the likelihood of finding SPD/RD to 3.7% in those demonstrating an excellent response to therapy, and increased the likelihood to 78.6% in those demonstrating a structural incomplete response. Among the earliest postoperative factors, only the Tg level at the first 131I ablation could predict long-term persistence/recurrence. The results highly support incorporating the RTR system to modify the initial risk estimate during follow-up among Chinese patients with WDTC.

Radioactive Iodine Remnant Ablation: The Beta-knife Completion Thyroidectomy.

The rationale and objectives for radioactive iodine (RAI) ablation remain perplexing to many. This review addresses the meaning, clinical context and the goals of “ablation”: the RAI treatment after a total thyroidectomy. This article also aims to clarify the definition of a total thyroidectomy and how a thyroid remnant can introduce a confounding factor in the postoperative management of patients with differentiated thyroid cancer. The implications of an existing thyroid remnant on RAI diagnostic imaging and serum thyroglobulin levels are discussed. This review provides a rational approach validating the utility of RAI remnant ablation regardless of the patient’s risk stratification.

Dynamic Risk Stratification for Predicting Recurrence in Patients with Differentiated Thyroid Cancer Treated Without Radioactive Iodine Remnant Ablation Therapy.

Increased incidence of small differentiated thyroid cancer (DTC) has emphasized the need for risk stratification and individualized disease management for these low risk DTCs. The aim of this study was to validate a new dynamic risk stratification (DRS) system for the prediction of structural recurrent/persistent disease in patients with DTC treated without radioactive iodine (RAI) remnant ablation therapy. This historical cohort study included 357 patients with DTC treated with lobectomy or total thyroidectomy without RAI therapy. We stratified patient response to initial treatment as excellent, indeterminate, biochemical incomplete, and structural incomplete according to the DRS system. During a median follow-up of 8.6 years, 3.6% patients had structural recurrent DTC. The response was excellent in 71.7% patients, indeterminate in 18.5%, biochemical incomplete in 8.4%, and structural incomplete in 1.4%. There were significant differences in DFS among the DRS groups (p < 0.001). The hazard ratio (HR) of recurrent/persistent disease was significantly higher in the biochemical incomplete group (HR = 20.8, p < 0.001) and structural incomplete group (HR = 243.3, p < 0.001) compared with the excellent group. However, the Tumor Node Metastasis staging system and the American Thyroid Association initial risk classification did not effectively predict recurrence of DTC. The new DRS system was effective for predicting risk of recurrent/persistent disease in patients with DTC who underwent lobectomy or total thyroidectomy without RAI remnant ablation.

Prediction of radioactive iodine remnant ablation failure in patients with differentiated thyroid cancer: A cohort study of 740 patients.

The purpose of this study was to detect parameters that could serve as predictors of radioactive iodine (I-131) ablation failure in patients with low-risk and intermediate-risk differentiated thyroid carcinoma (DTC). Our cohort study included 740 patients with DTC who received postoperative I-131 remnant ablation. Anthropometric, biochemical, and pathohistological parameters were analyzed and correlated with ablation outcome using multivariable logistic regression models. Treatment failure rates were higher in patients <53 years, with N1a classification, and lymph node capsular invasion. In patients with N1a disease, thyroglobulin (Tg) > 2.4 ng/mL predicted treatment failure with 93.8% sensitivity and 52.5% specificity, and in patients with N1b disease, Tg > 14.9 ng/mL with 77.8% sensitivity and 92.9% specificity. I-131 activity was not associated with treatment outcome. Patients < 53 years old, with higher Tg levels, N1a classification, and lymph node capsular invasion have a higher risk of ablation failure. Stimulated Tg is an excellent predictor of treatment failure in patients with N1 disease. © 2016 Wiley Periodicals, Inc. Head Neck 39: 109-115, 2017.

Comparison of Thyroglobulin Measurements Using Three Different Immunoassay Kits: A BRAMHS Tg-Plus RIA Kit, a BRAMHS hTg Sensitive Kryptor Kit, and a Beckman Coulter ACCESS Immunoassay Kit

BackgroundSecond-generation thyroglobulin immunometric assays (Tg-IMAs) have been developed with improved sensitivity. Our aim was to compare the diagnostic value of Tg-IMA measurements using a Kryptor (BRAHMS AG) kit (Tg-K) and an ACCESS (Beckman Coulter) kit (Tg-A) with that of the first-generation Tg measurement using a Tg-plus (BRAHMS AG) kit (Tg+).MethodsWe enrolled 82 differentiated thyroid cancer patients who underwent total thyroidectomy with radioactive iodine remnant ablation and who underwent diagnostic whole body scan using recombinant human thyroid stimulating hormone (rhTSH). The Tg+, Tg-K, and Tg-A were measured before rhTSH administration during levothyroxine treatment (suppressed Tg) from the same sample. Serum Tg+ was measured after rhTSH stimulation (stimulated Tg).ResultsSuppressed Tg+ was more significantly correlated with suppressed Tg-K (R2=0.919, P<0.001) than with suppressed Tg-A (R2=0.536, P<0.001). The optimal cut-off values of suppressed Tg+, Tg-K, and Tg-A for predicting stimulated Tg+ of 1 ng/mL were 0.3, 0.2, and 0.2 ng/mL, respectively. The sensitivity, specificity, and accuracy of suppressed Tg+ were 67%, 100%, and 90%, respectively; those of suppressed Tg-K were 83%, 90%, and 88%; those of suppressed Tg-A were 96%, 82%, and 87%, respectively. The positive predictive and negative predictive values of Tg+ were 100% and 87%, respectively; those of Tg-K were 79% and 92%; and those of Tg-A were 73% and 98%.ConclusionWe could not clearly demonstrate which kit had better diagnostic performance after comparison of first-generation Tg measurements with Tg-IMA measurements. Also, there were kit-to-kit variations between Tg-IMA kits. Suppressed Tg measured by Tg-IMA was insufficient to completely substitute for a stimulated Tg measurement.

The Effectiveness of Radioactive Iodine Remnant Ablation for Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-analysis.

This systematic review and meta-analysis aimed to evaluate the effectiveness of radioactive iodine (RAI) remnant ablation for thyroid cancer-related outcomes of patients with papillary thyroid microcarcinoma (PTMC). A systematic literature search of PubMed, EMBASE OvidSP, and EBSCO was conducted. Studies were selected that provided multivariable analysis of the effectiveness of RAI ablation or provided specific data of a 10 years history of thyroid cancer-related outcomes in patients that presented with PTMC. Nineteen studies met the inclusion criteria. A multivariable analysis of the effectiveness of RAI ablation for any recurrence or thyroid cancer-related mortality in patients with PTMC was performed in several studies, among which only one study reported a positive result. Furthermore, for PTMC patients treated by total or near-total thyroidectomy (TT/NT), with or without RAI ablative therapy, the meta-analysis suggested that RAI ablation did not decrease the 10 years history of any tumor recurrence (relative risk [RR] 0.96; 95% confidence interval [CI] 0.63-1.48; P = 0.87), locoregional recurrence (RR 1.15; 95% CI 0.75-1.76; P = 0.51), distant metastases (RR 0.32; 95% CI 0.08-1.32; P = 0.11) or thyroid cancer-related mortality (RR 0.76; 95% CI 0.22-2.63; P = 0.66). With regard to multivariable analyses, there was almost no positive treatment effect of RAI ablation noted for patients with PTMC. For PTMC patients already treated by TT/NT, incremental RAI ablation may not be beneficial at decreasing the 10 years recurrence of PTMC or incidence of thyroid cancer-related mortality.

Effect of Hashimoto thyroiditis on low-dose radioactive-iodine remnant ablation.

Radioactive-iodine remnant ablation is an integral part of the papillary thyroid carcinoma (PTC) treatment. Although a minimum dose is usually recommended, there is controversy as to whether the low-dose (1100 MBq) radioactive-iodine remnant ablation is adequate for selected patients. A retrospective cohort study was conducted on 691 patients. Patients with no remnant thyroid on the follow-up whole body scan and low stimulated thyroglobulin (sTg) level (<2.0 ng/mL) were deemed as successful treatment cases. Initial low-dose radioactive-iodine remnant ablation was successful in 431 patients (62.3%). Multivariate analysis demonstrated a negative correlation between successful radioactive-iodine remnant ablation and coexisting Hashimoto thyroiditis based on histopathology diagnosis (odds ratio [OR] = 3.23; p < .001) as well as elevated preablation sTg (OR = 1.24; p < .001). Our data suggest that coexisting Hashimoto thyroiditis and elevated sTg are negative predictive factors for successful low-dose radioactive-iodine remnant ablation treatment. An appropriate risk-adjusted approach may improve the efficacy of radioactive-iodine remnant ablation treatment. © 2015 Wiley Periodicals, Inc. Head Neck 38: E730-E735, 2016.

Radioiodine-remnant ablation in low-risk differentiated thyroid cancer: pros.

Differentiated thyroid carcinomas are typically treated with total thyroidectomy as initial therapy. Subsequent radioactive iodine (RAI) ablation destroys post-surgical thyroid remnants, can additionally provide adjuvant therapy of residual and metastatic thyroid cancers, and enhances the sensitivity and specificity of further diagnostic studies. There is current controversy regarding whether a large number of patients, broadly considered to have "low-risk" disease, should be provided RAI ablation. This is consequent to over-reliance on short-term studies, under-appreciation of the value of RAI remnant ablation, and inflation of the side effects of RAI therapy. A balanced assessment of all of these issues provides justification to utilize post-surgical radioiodine ablation, even in cases that are considered low risk on the basis of surgical findings.

RAI thyroid bed uptake after total thyroidectomy: A novel SPECT-CT anatomic classification system.

Recent, more selective use of radioactive iodine (RAI) has led to reevaluation of the clinical importance of achieving complete total thyroidectomy with minimal residual normal thyroid tissue. We utilize the improved localization by post-RAI remnant ablation, single photon emission computerized tomography-computed tomography (SPECT-CT) to define specific anatomic sites of residual RAI-uptake foci after total thyroidectomy for differentiated thyroid cancer (DTC) and to provide a novel classification system relating uptake to thyroid anatomy and preservation of adjacent neural structures. Retrospective. Radioactive iodine-uptake foci in thyroid bed were localized by SPECT/CT imaging at the time of RAI remnant ablation in 141 DTC patients undergoing total thyroidectomy. Minimal residual RAI uptake (median 0.32% at 24 hours) in the thyroid bed was detected by diagnostic planar whole body scans in 93% and by posttherapy SPECT/CT imaging in 99% of subjects. Discrete RAI uptake foci were identified on the SPECT/CT imaging at Berry's ligament (87%), at superior thyroid poles (79%), in paratracheal-lobar regions (67%), in isthmus-region (54%), and in pyramidal lobe (46%). Despite the residual foci, the nonstimulated thyroglobulin (Tg) prior to remnant ablation (with a median thyroid-stimulating hormone of 0.36 m IU/L) was < 0.6 ng/mL in 53% and < 1 ng/mL in 73% of cases. After extracapsular total thyroidectomy, highly sensitive detection tools identify microscopic residual RAI avid foci in thyroid bed in the majority of patients. These foci can be classified as 1) neural-related and 2) capsule-related. These common residual foci have no relationship to postoperative Tg, suggesting that attempts at radical removal of thyroid tissue in these locations may not be warranted. 4.

Comparison of fine-needle aspiration cytology, ultrasound and thyroglobulin examination for the differential diagnosis of enlarged neck lymph nodes in patients with differentiated thyroid cancer after radioactive iodine remnant ablation

Objective To compare the value of fine-needle aspiration cytology (FNAC),Tg,TgAb and ultrasonography (US) for the differential diagnosis of lymph node metastasis in patients with DTC after operation and radioactive iodine remnant ablation.Methods A total of 61 DTC patients with enlarged lymph nodes detected by US or physical examination after operation and radioactive iodine remnant ablation were included.FNAC was performed on the lymph nodes under US guidance within one week and the results were compared with those of Tg,TgAb and US.Final results were confirmed by comprehensive FNAC,posttreatment whole,body scan (Rx-WBS) and clinical follow-up.x2 test and Fisher's exact test were performed.Resuits Fifty-eight DTC patients had successful FNAC results,and 40 patients were confirmed as malignant and 18 as benign after overall assessment.FNAC identified 39 malignant and 19 benign cases.The coincidence rates of FNAC with postoperative pathological diagnosis and Rx-WBS for malignant cases were 100％ (20/20) and 78.9％ (15/19),respectively.For the benign cases,the coincidence rates of FNAC with clinical follow-up and Rx-WBS were 93.3％ (14/15)and 4/4,respectively.The sensitivity,specificity and accuracy were 97.5％(39/40),100％(18/18) and 98.3％(57/58) for FNAC; 87.5％(35/40),55.6％(10/18) and 77.6％(45/58) for US; 92.5％(37/40),72.2％(13/18) and 86.2％(50/58) for Tg combined with TgAb (Tg/TgAb).The accuracy of FNAC was higher than that of US and Tg/TgAb(x2 =4.336,11.697,both P＜0.05),while US and Tg/TgAb showed no significant difference (x2 =1.450,P＞0.05).Tg/TgAb and US results were consistent in 39 cases with a diagnostic accuracy of 97.4％ (38/39) verified by FNAC,while the other 19 cases with inconsistent Tg/TgAb and US results were verified as malignant in 4 cases and benign in 15 cases.Conclusions FNAC is superior to US and Tg/TgAb in the evaluation of lymph node metastasis in DTC patients after operation and radioactive iodine remnant ablation.FNAC should be recommended particularly when Tg/TgAb and US had inconsistent results. Key words: Thyroid neoplasms; Lymph nodes; Biopsy, fine-needle; Ultrasonography; Thyroglobulin

Higher Administered Activities of Radioactive Iodine Are Associated with Less Structural Persistent Response in Older, but Not Younger, Papillary Thyroid Cancer Patients with Lateral Neck Lymph Node Metastases

While radioactive iodine (RAI) adjuvant therapy is commonly recommended for most papillary thyroid cancer patients presenting with large volume nodal involvement, it remains unclear if such therapy impacts the disease-specific recurrence rate and overall survival. In this study, we compared the risk of achieving a structural persistent response after low administered activity (100 mCi), intermediate administered activity (150 mCi), and high administered activity (>200 mCi) RAI adjuvant therapy in patients presenting with pathologic N1b disease. This was a retrospective review of 181 papillary thyroid cancer patients with N1b disease treated with total thyroidectomy, neck dissection, and RAI remnant ablation. Dose-response relationships were determined between the administered activity of (131)I and the best response to initial therapy. Out of the 181 patients, only 39% achieved no clinical evidence of disease (NED) after initial therapy. Young patients (Stage I) had a statistically nonsignificant trend toward higher rates of NED with increasing dose (34% low activity, 36% intermediate activity, 46% high activity), but there was no evidence of dose-response effect with regard to the likelihood of having a structural persistent response to initial therapy or the likelihood of having persistent biochemical evidence of disease. However, analysis of the older patients (Stage IVa) did reveal a trend toward statistically significant dose-response relationships with increasing administered activities being associated with lower rates of structural persistent response (46% low activity, 23% intermediate activity, 17% high dose). Unfortunately, the lower rate of structural persistent response only modestly increased the likelihood that patients would be NED but was instead associated with a higher proportion of patients being classified as having biochemical persistent disease at 12-18 months. It appears that administering more than 100 mCi of RAI as adjuvant therapy in N1b disease is unlikely to improve the initial response to therapy. This is especially true for the younger (Stage I) patients. It is plausible that administered activities of 150-260 mCi may be associated with an improved response to initial therapy in older patients (Stage IVa) who are probably at highest risk of having poor outcomes, but the potential benefit from RAI should be balanced against potential adverse effects in those patients.

Sentinel Lymph Node Biopsy Status Correlates With Postoperative Stimulated Thyroglobulin Levels in Low-Risk Papillary Thyroid Cancer Patients

Radioactive iodine (RAI) remnant ablation in low-risk papillary thyroid cancer (PTC) is controversial. Current patient selection guidelines recommend the use of postoperative stimulated thyroglobulin (stim-Tg), neck dissections, and sonography but fail to include sentinel lymph node biopsy (SLNB). The objective of this study was to evaluate the correlation between SLNB status and postoperative stimulated thyroglobulin as a surrogate marker of clinical outcome. Retrospective chart review of low-risk PTC patients who underwent a total thyroidectomy with SLNB at the McGill Thyroid Cancer Center. SLNBs were obtained using methylene blue dye. Biochemical measurements were acquired between 4 and 12 weeks postoperatively. Statistical analyses were performed using logistic regression models and receiver operating characterisitc (ROC) curves. A P-value <.05 was considered significant. Ninety-six patients were included in this study. The positive SLNB rate was 14.6%. The mean postoperative Tg level was 1.41 μg/L. There were no significant correlations between the SLNB and the covariates analyzed (age, gender, histology, tumor size, and thyrotropin levels). Patients with negative SLNB were significantly more likely to have a lower stim-Tg (P<.0001). When postoperative Tg was analyzed as a categorical variable, a threshold of <1 μg/L was significantly associated with a negative SLNB, with a sensitivity and specificity (determined by ROC curves) of 0.86 and 0.88, respectively. There exists a correlation between SLNB and postoperative Tg. This creates the possibility of a new approach to RAI administration among low-risk PTC patients incorporating SLNB to the current guidelines.

Columnar variant of papillary carcinoma in the thyroglossal duct cyst with progression to lung metastasis

Thyroglossal duct cyst (TGDC) carcinoma generally shows a favorable prognosis. If metastasis is present latently, it may not threaten the patient’s life immediately. It has been shown, however, that larger than 1 cm papillary carcinoma (PC), level VI metastasis to the lymph node (LN), which is the nearest to the thyroid, independently predicts a worse prognosis. In the case presented herein, a 61-year-old female patient was diagnosed with an about 3 cm PC in the TGDC, particularly the columnar variant subtype, one of the aggressive variants. She had occult papillary thyroid microcarcinoma, but no LN metastasis. Even though she underwent the Sistrunk procedure and total thyroidectomy with central compartment neck dissection followed by high-dose radioactive iodine remnant ablation, however, the cancer cells spread to level IV neck LN, and finally to the lung. Therefore, when a patient is diagnosed with an aggressive histologic variant of PC in the TGDC, even without LN metastasis, the invasive surgical approach and close postoperative surveillance are necessary, with consideration of the risk of disease progression. Therefore, if it is possible to stratify the risk for patients, higher-risk patients can be offered a more invasive therapeutic approach.

Pathologic spectrum of lymphocytic infiltration and recurrence of papillary thyroid carcinoma.

PurposeThe aim of this study was to investigate the prognosis of papillary thyroid carcinoma (PTC) patients according to different pathologic grades of lymphocytic thyroiditis (LT).Materials and MethodsThis study included 144 PTC patients who underwent total thyroidectomy with radioactive iodine remnant ablation therapy. Pathologic grades of LT were separated at two points, chronic lymphocytic thyroiditis (CLT) and Hashimoto thyroiditis (HT). Patients were divided into two groupings according to the presence of the diseases (Grouping 1; patients with CLT or HT and without CLT or HT, Grouping 2; patients with HT and without HT). The groupings were compared according to recurrence, clinicopathologic and ultrasound (US) characteristics, and disease free survival.ResultsOf 144 patients, 41 had CLT and 19 had HT. There were 10 patients (6.9%) with tumor recurrence. In both groupings, the presence of calcification was more frequently associated with patients with LT (p=0.041 and 0.047, respectively). In Grouping 2, the mean age at diagnosis was older in patients without HT compared to patients with HT (p=0.032). On multivariate analysis, the presence of LT was not an independent predictor of recurrence in both groupings. For both groupings, pathologic tumor size and taller than wide shape on US were independent predictors of recurrence. The presence of LT in PTC patients did not affect recurrence.ConclusionThere was no relationship between PTC prognosis and different grades of LT. Pathologic tumor size and taller than wide shape on ultrasound were independent predictors of PTC recurrence regardless of concurrent LT.