Structural Incomplete Response Research Articles

8549 A Pre-ablative Stimulated Thyroglobulin Value That Predicts ATA High Risk Patients and Their Treatment Response

Abstract Disclosure: H. Gondaliya: None. N. Nangadda: None. D. Bhat: None. K.S. Khadilkar: None. S. Kumbenahalli Siddegowda: None. B.G. Sooragonda: None. A. Shetty: None. S. Kannan: None. In ATA risk stratification system for differentiated thyroid cancer (DTC), one of the variables placing patients in ATA high risk category is thyroglobulin (Tg) suggestive of distant metastases. However there is no defined cut-off Tg level for guiding the clinicians. We aimed to determine pre-ablative stimulated Tg (psTg) value that predicts ATA high risk patients (based on non-Tg parameters) and their treatment response on follow up. This was an ambispective observational study of 285 patients with DTC treated at our centre from April 2017 to November 2022. psTg was measured in all patients 3-4 weeks after surgery and they were subjected to RAIA depending on clinician’s discretion and followed up using the ATA dynamic risk stratification every 6 months. The cohort was divided into two groups: ATA high risk and ATA non-high risk (Low and intermediate risk). Patients among high risk group were divided based on response to treatment into structural incomplete group and non-structural incomplete group (Excellent, Indeterminate and Biochemically incomplete response). The mean age of the study population was 41±15 years and 68% (n=194) were female and 87% (n=249) were papillary thyroid cancer (PTC) and 13% (n=36) were Follicular Thyroid Cancer (FTC). Median duration of follow up was 2.95 years (IQR: 1.42 - 5.12). Among those with PTC, 75% were Classic, 15% Follicular variant and 10% aggressive variants that included tall cell, hobnail, diffuse sclerosing and columnar variant. On ATA risk stratification, 81.75% (n=233) patients were in non-high risk group with median psTg 3.4 ng/ml (IQR 0.5-12.2) and 18.25% (n=52) were in high-risk group with median psTg 150.5 ng/ml (IQR 7.15-439.5). On ROC analysis of all the patients, a psTg value >53.3 ng/ml was predictive of ATA high risk group with PPV of 64%; NPV of 93.5% and AUC 0.81. In ATA high-risk group, there were 73% (n=38) of patients with structural incomplete response on follow up and their median psTg was 287 ng/ml (IQR 95-500) and there were 27% (n=14) with non-structural incomplete response and their median psTg level of 6.2 ng/ml (IQR 2.3-110). A psTg value >53 ng/ml discriminated structural incomplete from non-structural incomplete response with PPV of 77%; NPV 87% and AUC 0.83. A psTg value >53 ng/ml not only predicts ATA high risk patients but also indicates those who are likely to remain with structural residual disease at follow up of 3 years. Presentation: 6/1/2024

Radiofrequency ablation (RFA) for structural incomplete response (SIR) to therapy in differentiated thyroid cancer (DTC)

Radiofrequency ablation (RFA) for structural incomplete response (SIR) to therapy in differentiated thyroid cancer (DTC)

Tracking dynamic evolution of low- and intermediate-risk differentiated thyroid cancer: Identification of individuals at risk of recurrence.

The generally good prognosis of low- and intermediate-risk differentiated thyroid cancer (DTC) underscored the need to identify those few patients who relapse. Records of 299 low- or intermediate-risk DTC patients (mean follow-up 8.2 ± 6.2 years) were retrospectively reviewed. The sample was classified following the American Thyroid Association (ATA) dynamic risk stratification (DRS) system. After classifying patients according to DRS at the first visit following initial therapy (FU1), structural recurrence occurred in 2/181 (1.1%), 5/81 (6.2%) and 13/26 (50.0%) with excellent, indeterminate and biochemical incomplete response to treatment, respectively. All relapses but one happened within 5 years from FU1. Univariate analysis comparing excellent, indeterminate and biochemical incomplete with structural incomplete responses at the end of the follow-up, identified tumour size (p < .001), T status (<0.001), positive lymph nodes (N) (p < .01), multifocality (p < .004), need of additional radioactive iodine (RAI) (p < .0001) and first DRS status (p < .0003) as risk factors of recurrence. In the multivariate analysis, only RAI remained statistically significant (p < .02). Comparison between excellent and indeterminate with biochemical and structural incomplete responses, identified tumour size (p < .0004), T (p < .01), N (p < .0001), bilaterality (p < .03), first DRS status (p < .0001) and RAI (p < .001) as recurrence risk factors. T (p < .01) and first DRS (p < .0006) were confirmed in the multivariate analysis. Patients with DTC classified as low- or intermediate-risk of recurrence with excellent response to treatment at FU1 rarely develop structural disease and this occurs almost exclusively in the first 5 years. Initial DRS status is an accurate tool for determining the risk of recurrence.

Improving the Risk Prediction of the 2015 ATA Recurrence Risk Stratification in Papillary Thyroid Cancer.

Various prognostic factors are expected to refine the American Thyroid Association (ATA) recurrence risk stratification for patients with papillary thyroid cancer (PTC). However, it remains unclear to what extent integrating these factors improves patient treatment decision-making. We developed two predictive models for structural incomplete response (SIR) at the one-year follow-up visit, based on comprehensive clinical data from a retrospective cohort of 2539 patients. Model 1 included the recurrence risk stratification and lymph node features (i.e., number and ratio of metastatic lymph nodes, N stage). Model 2 further incorporated preablation stimulated thyroglobulin (s-Tg). An independent cohort of 746 patients was used for validation analysis. We assessed the models' predictive performance compared to the recurrence risk stratification using the integrated discrimination improvement (IDI) and the continuous net reclassification improvement (NRI). The clinical utility of the models was evaluated using decision curve analysis. Both Model 1 and Model 2 outperformed the recurrence risk stratification in predicting SIR, with improved correct classification rates (Model 1: IDI=0.02, event NRI=42.31%; Model 2: IDI=0.07, event NRI=53.54%). The decision curves indicated that both models provided greater benefits over the risk stratification system in clinical decision-making. In the validation set, Model 2 maintained similar performance while Model 1 did not significantly improve correct reclassification. The inclusion of lymph node features and s-Tg showed potential to enhance the predictive accuracy and clinical utility of the existing risk stratification system for PTC patients.

Lobectomy in patients with differentiated thyroid cancer: experience of a Chilean tertiary center.

Thyroid lobectomy (TL) is an appropriate treatment for up to 4 cm intrathyroidal differentiated thyroid cancer (DTC). There is scarce data regarding TL outside first-world centers. Our aim is to report a cohort of patients with DTC treated with TL in Chile. We included DTC patients treated with TL, followed for at least 6 months, characterized their clinicopathological features and classified their risk of recurrence and response to treatment. Eighty-two patients followed for a median of 2.3 years (0.5-7.0). Seventy-three (89%) patients had papillary, 8 (9.8%) follicular and 1 (1.2%) high-grade DTC. The risk of recurrence was low in 56 (68.3%) and intermediate in 26 (31.7%). Eight (9.8%) patients required early completion thyroidectomy and radioiodine. At last follow-up, 52 (70.3%) had excellent, 19 (25.7%) had indeterminate, and 1 (1.4%) had structural incomplete response. In a developing country, TL is an adequate option for appropriately selected DTC patients.

Impact of age on tumor characteristics and treatment outcomes in pediatric Differentiated Thyroid Carcinoma.

There is a tendency to use data generated for adults in the management of pediatric Differentiated Thyroid Carcinoma, neglecting the clinical peculiarities of this condition in childhood. This study aimed to assess and compare the clinical-epidemiological characteristics and their significance in the evolution of thyroid carcinoma diagnosed in childhood across different age groups. Seventy-seven patients diagnosed with Differentiated Thyroid Carcinoma (DTC) up to 21 years old were selected and divided into different age groups: up to 10 years, 11 to 18 years, and 19 to 21 years old. Clinical-epidemiological data and their influence in the disease progression were analyzed and compared across age groups. Patients diagnosed below 10 years of age were associated with tumors showing extrathyroidal extension, metastasis in regional lymph nodes, higher levels of stimulated thyroglobulin in the diagnostic iodine-131 whole-body scan (WBS), and under TSH suppression in the last assessment. Additionally, pulmonary metastasis were associated in both diagnostic and post-radioiodine dose WBSs in these younger patients. Analysis of findings in the post-radioiodine therapy WBS revealed significant differences between all age groups (p = 0.0029). The time of diagnosis was identified as a factor associated with an excellent response in subgroups up to 18 years and up to 21 years. No factors associated with dynamic responses over the 1st, 3rd and 5th years of follow-up and the persistence/recurrence of the disease were identified in the subgroup up to 18 years. In the subgroup up to 21 years, having an incomplete structural response in the 3rd year of follow-up increased the chances of recurrent or persistent response by 5.5 times, and by 32.6 times if found in the 5th year of follow-up. Younger patients exhibited more aggressive tumor characteristics and underwent more rigorous treatment. However, treatment response and disease status in the last assessment, whether free or recurrent/persistence, were similar when comparing the age groups of 11 to 18 and 19 to 21 years. Nonetheless, responses obtained in the 3rd and 5th years post-treatment emerged as factors associated with the persistence/recurrence of the disease in the last assessment in the age group up to 21 years but not in patients diagnosed up to 18 years, a relevant distinction considering the tumor behavior in defining the pediatric age range in thyroid cancer.

A hybrid machine learning model combining association rule mining and classification algorithms to predict differentiated thyroid cancer recurrence.

Differentiated thyroid cancer (DTC) is the most prevalent endocrine malignancy with a recurrence rate of about 20%, necessitating better predictive methods for patient management. This study aims to create a relational classification model to predict DTC recurrence by integrating clinical, pathological, and follow-up data. The balanced dataset comprises 550 DTC samples collected over 15 years, featuring 13 clinicopathological variables. To address the class imbalance in recurrence status, the Synthetic Minority Over-sampling Technique for Nominal and Continuous (SMOTE-NC) was utilized. A hybrid model combining classification algorithms with association rule mining was developed. Two relational classification approaches, regularized class association rules (RCAR) and classification based on association rules (CBAR), were implemented. Binomial logistic regression analyzed independent predictors of recurrence. Model performance was assessed through accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score. The RCAR model demonstrated superior performance over the CBAR model, achieving accuracy, sensitivity, and F1 score of 96.7%, 93.1%, and 96.7%, respectively. Association rules highlighted that papillary pathology with an incomplete response strongly predicted recurrence. The combination of incomplete response and lymphadenopathy was also a significant predictor. Conversely, the absence of adenopathy and complete response to treatment were linked to freedom from recurrence. Incomplete structural response was identified as a critical predictor of recurrence risk, even with other low-recurrence conditions. This study introduces a robust and interpretable predictive model that enhances personalized medicine in thyroid cancer care. The model effectively identifies high-risk individuals, allowing for tailored follow-up strategies that could improve patient outcomes and optimize resource allocation in DTC management.

Second radioiodine treatment in patients with differentiated thyroid carcinoma: Causes and effects

IntroductionPatients with incomplete response to initial therapy of thyroid cancer can be managed with ongoing observation or potentially additional therapies.Our aim was to assess the effect of a second radioactive iodine treatment (RAIT) and its relationship with causes and clinical variables. Material and methodsPatients undergoing a second RAIT for biochemical or structural incomplete response to initial therapy of DTC were retrospectively included (n=120). They were categorised based on the American Thyroid Association (ATA) classification of response to initial therapy.Patients were reclassified in the following 6–18 months after second RAIT based on imaging findings and measurements of thyroglobulin and antithyroglobulin antibody levels.The associations of a downgrading of response category and progression-free survival (PFS), and the related variables, were evaluated. ResultsSixty-six patients (55%) had a downgrading on ATA response category after second RAIT. A significant interdependence of causes for second RAIT and outcomes was found (χ2=29.400, p=0.001), with patients with neck reoperation showing a higher rate of indeterminate or excellent responses.A significant association between ATA response to second RAIT and absence of structural progression was found (χ2=44.914, p<0.001), with less structural progression in patients with downgrading on ATA response (χ2=30.914, p<0.001). There was also significant interdependence to some clinical variables, such as AJCC stage (χ2=8.460, p=0.015), ATA risk classification (χ2=10.694, p=0.005) and initial N stage (χ2=8.485, p=0.004). ConclusionsIn selected cases, a second RAIT could lead to more robust responses with a potential improvement in prognosis in patients with incomplete response to initial DTC treatment.

Impact factors of benefiting from initial 131 I ablation in patients with intermediate-risk differentiated thyroid carcinoma: a study based on a re-evaluation of therapeutic response.

This study was carried out to confirm whether patients with intermediate-risk differentiated thyroid cancer (DTC) could benefit from initial 131 I ablation and to identify the factors that impacted the benefit. We retrospectively assessed a cohort of 548 patients with intermediate-risk DTC who were classified into structural incomplete response (SIR), biochemical incomplete response (BIR), indeterminate response (IDR), and excellent response (ER) groups according to the ATA guidelines (version 2015). A downgrade in the classification, such as from initial SIR to final BIR, IDR, or ER, from BIR to IDR or ER, and from initial IDR to final ER, was defined as benefiting from initial 131 I ablation (benefit group). Non-downgraded classification meant non-benefit. 64.78% of patients benefited from the initial 131 I ablation in the final re-evaluation. Gender (OR = 0.038, P = 0.002), interval time (OR = 0.038, P = 0.002) and serum ps-Tg (OR = 0.961, P = 0.001) were independent prognostic factors for benefiting from initial 131 I ablation, with the cutoff value were 5 months and 19.08 ng/ml. Patients with intermediate-risk DTC could benefit from initial 131 I ablation. Female patients with intermediate-risk DTC whose interval time <5 months and ps-Tg <19.08 ng/ml were more likely to benefit. Early 131 I ablation for such patients is beneficial for achieving a complete therapeutic response.

The potential association of peripheral inflammatory biomarkers in patients with papillary thyroid cancer before radioiodine therapy to clinical outcomes.

Neutrophil-lymphocyte ratio (NLR), markers-lymphocyte-to-monocyte ratio (LMR), and platelet to-lymphocyte ratio (PLR) have potential roles as prognostic biomarkers in various cancers. The study was evaluated to investigate the predictive value of the peripheral inflammatory biomarkers in patients with papillary thyroid carcinoma (PTC) before radioiodine therapy to the response of clinical outcomes. We retrospectively analyzed the patients diagnosed with PTC at the Second Hospital of Shandong University between September 2018 and January 2020. Patients were divided into low and high inflammatory biomarker groups based on median values. The area under the receiver operating characteristic curves (ROC) and logistic regression were used to explore the potential risk factors. A total of 692 patients were enrolled, which included 197 (28.4%) males and 495 (71.6%) females. The median values of NLR, LMR and PLR of these patients were 1.7 (range 0.3-5.7), 7.1 (range 1.1-23.4) and 137.6 (range 27.6-497.5), respectively, and the mean values were 1.95 ± 0.82, 7.4 ± 2.5 and 148.7 ± 54.8, respectively. Compared to the lower PLR group, the higher group was significantly associated with gender, tumor size, N stage and thyroglobulin level (P<0.05). At the end of follow-up, 75.5% (523/692), 13.3% (91/692), 4.5% (31/692), and 6.7% (47/692) of patients were evaluated as excellent response (ER), indeterminate response (IDR), structural incomplete response (SIR), and biochemical incomplete response (BIR) respectively. In term of clinical outcomes, the NLR, LMR and PLR showed relatively low discriminative power (P≥0.05). We found that higher PLR values was associated with poor clinicopathological features in PTC. However, the peripheral inflammatory indicators (NLR, LMR and PLR) may be insufficient to predict short-term clinical outcomes of patients with radioiodine therapy.

Second radioiodine treatment in patients with differentiated thyroid carcinoma: Causes and effects

IntroductionPatients with incomplete response to initial therapy of thyroid cancer can be managed with ongoing observation or potentially additional therapies.Our aim was to assess the effect of a second radioactive iodine treatment (RAIT) and its relationship with causes and clinical variables. Material and methodsPatients undergoing a second RAIT for biochemical or structural incomplete response to initial therapy of DTC were retrospectively included (n=120). They were categorised based on the American Thyroid Association (ATA) classification of response to initial therapy.Patients were reclassified in the following 6–18 months after second RAIT based on imaging findings and measurements of thyroglobulin and antithyroglobulin antibody levels.The associations of a downgrading of response category and progression-free survival (PFS), and the related variables, were evaluated. ResultsSixty-six patients (55%) had a downgrading on ATA response category after second RAIT. A significant interdependence of causes for second RAIT and outcomes was found (χ2=29.400, p=0.001), with patients with neck reoperation showing a higher rate of indeterminate or excellent responses.A significant association between ATA response to second RAIT and absence of structural progression was found (χ2=44.914, p<0.001), with less structural progression in patients with downgrading on ATA response (χ2=30.914, p<0.001). There was also significant interdependence to some clinical variables, such as AJCC stage (χ2=8.460, p=0.015), ATA risk classification (χ2=10.694, p=0.005) and initial N stage (χ2=8.485, p=0.004). ConclusionsIn selected cases, a second RAIT could lead to more robust responses with a potential improvement in prognosis in patients with incomplete response to initial DTC treatment.

The American Thyroid Association risk stratification and long-term outcomes of differentiated thyroid cancer: a 20-year follow-up of patients in Saudi Arabia.

Studies have reported differing factors associated with poor outcomes in patients with differentiated thyroid cancer (DTC). We aimed to describe our 20 years of experience in the management of thyroid cancer (TC) and identify predictors of treatment outcomes. We conducted a retrospective review of medical records of patients with TC seen in the Thyroid Center at King Saud University Medical City (KSUMC) in Riyadh, Saudi Arabia, between the years 2000 and 2020. Demographic and clinical data including pathological characteristics were collected. The American Thyroid Association (ATA) risk stratification was determined for all patients at the postoperative period as well as the response to therapy at the final follow-up visit. A total of 674 patients (mean age: 47.21 years) with TC, 571 (84.7%) of which were women, were included. There were 404 (60.0%) patients with ATA low risk, 127 (18.8%) with intermediate risk, and 143 (21.2%) with high-risk histology. Overall, 461 patients (68.4%) had an excellent response to treatment, 65 (9.6%) had an indeterminate response, 83 (12.3%) had a biochemical incomplete response, and 65 (9.6%) had a structural incomplete response. Patients who had an excellent response were mostly ATA low risk (n = 318 of 431, 68.1%), whereas 40 of 65 patients (61.5%) of those with ATA high-risk histology had a structural incomplete response to treatment. There were significantly more women who had an excellent response compared with men. Obesity, lymphovascular invasion, and size of the tumor were significant predictors of worse outcomes to therapy. Tumor size, lymphovascular invasion, and obesity are strong predictors of a worse response to therapy among patients with TC. Patients with obesity should be carefully followed up regardless of their risk stratification in light of the recent compelling evidence associating obesity with thyroid cancer and its higher risk of a worse disease outcome. ATA risk stratification is well correlated with patient long-term outcomes.

Risk Stratification of Differentiated Thyroid Cancer: A Single-Center Study in Basrah.

Background Differentiated thyroid cancer is a common endocrine cancer; most of it has an indolent course and favorable outcomes, with a subset of patients having the risk of disease recurrence, which can be assessed using the fixed American Thyroid Association (ATA) risk stratification system or the dynamic response to therapy risk stratification that can be modified during patients follow-up. Aim The aim of this article is to assess the risk stratification of patients having differentiated thyroid cancer. Methods This is aretrospective cross-sectional study in which we evaluated medical records of 75 patients having differentiated thyroid cancer to assess the baseline ATA risk of recurrence and compared it to the results of dynamic risk stratification in response to therapy at 6-12 months post-surgery and at the last visit. Thyroglobulin level, anti-thyroglobulin antibody, thyroid ultrasound, and cytopathological examination were used to determine dynamic response to therapy and divided subjects into four groups: excellent response (ER), biochemical incomplete response (BIR), structural incomplete response (SIR), and indeterminate response (IR). Results At baseline, 55 patients had low risk, 14 patients had intermediate risk, and six patients had high risk. At 6-12 months post-surgery, in the low-risk group, ER, BIR, and IR responses were observed in 56.4%, 5.5%, and 38.2% of patients, respectively, and none of them exhibited SIR. In the intermediate-risk group, ER, BIR, and IR responses were observed in 57.1%, 21.4%, and 21.4% of patients, respectively, and none exhibited SIR. Among the high-risk group, two patients had ER, two patients had BIR, one patient had IR, and one patient had SIR. At the last visit, ER, BIR, and IR were observed in 65.5%, 9.1%, and 25.5% of low-risk patients, respectively, and no patient developed SIR. In the intermediate-risk group, ER, BIR, and IR were observed in 50%, 21.4%, and 28.6% of patients, respectively, and no patients developed SIR. Among the high-risk group, three patients achieved ER, one had BIR, one had IR, and one had SIR. Conclusion Most of the differentiated thyroid cancers in this study are low-risk. Dynamic risk stratification appears to be an effective tool in the follow-up of this population of patients having differentiated thyroid cancer.

BRAF V600E mutation in papillary thyroid microcarcinoma: is it a predictor for the prognosis of patients with intermediate to high recurrence risk?

The BRAFV600E mutation is the universal genetic mutation in papillary thyroid microcarcinoma (PTMC). The present study is to estimate the role of the BRAFV600E mutation in the clinical outcome of PTMC with intermediate to high recurrence risk after radioactive iodine (RAI) therapy, which is considered to be an indolent tumor. We conducted a single-center retrospective study. Between May 2016 and March 2019, PTMC patients with known BRAFV600E status who received RAI therapy were reviewed at the Second Hospital of Shandong University. Treatment and follow-up were defined according to criteria used in the 2015 ATA guidelines. The association between the BRAFV600E mutation and clinicopathological characteristics, response to RAI therapy, and recurrence after a period of follow-up were analyzed. Propensity score matching (PSM) and logistic regression were used to control confounding variables. Of the 322 patients with intermediate to high recurrence risk in PTMC, the mean age of the patients were 43.7 ± 12.2 years, and 72.1% were women. BRAFV600E mutation was found in 64.9% (209/322). After PSM, 112 pairs of patients were matched, and except for multifocality (P = 0.001), extrathyroidal invasion (P = 0.003) and tumor size (P = 0.03), there was no significant difference in all baseline characteristics between the two groups. An excellent response (ER) to RAI therapy was observed in 273 patients (84.7%). At the end of the study, 17(5.2%) and 6(1.8%) patients showed structural incomplete response (SIR) and biochemical incomplete response (BIR) status. The proportion of patients who achieved ER status in the BRAFV600E mutation positive and negative groups was 86.6% and 81.4%, respectively. Kaplan-Meier analyses showed that the BRAFV600E mutation was not related to lower ER reached time. The median follow-up was 51 months. We found the BRAFV600E mutation was associated with multifocality, extrathyroidal invasion, and tumor size in papillary thyroid microcarcinoma. However, the BRAFV600E mutation had no significant association with clinical outcomes in patients with intermediate to high recurrence risk after RAI therapy. Furthermore, the extra-thyroid uptake results and distant metastasis had been proven to be independent factor predicting the clinical response. ChiCTR2200062911.

Analysis of the clinical factors affecting excellent response of Iodine-131 treatment for pulmonary metastases from differentiated thyroid cancer

BackgroundIodiene-131 (131I) treatment is the primary therapeutic approach for imaging 131I-avid pulmonary metastases. The response to radioiodine (RAI) treatment is an important prognostic factor in patients with pulmonary metastases from differentiated thyroid cancer (DTC). Patients who achieve an excellent response (ER) to 131I treatment show significantly reduced disease-related mortality. This study aimed to retrospectively analyse the clinical data and therapeutic effects of 131I treatment in patients with DTC and pulmonary metastases and to screen out the clinical factors affecting ER. Materials and methodsThe study included a total of 75 patients with exclusively Iodine-131 avid (131I-avid) pulmonary metastases who underwent 131I treatment. Relevant clinical data for these patients were collected. Following treatment, the status of DTC metastatic lesions was categorized as follows: excellent response (ER), biochemical incomplete response (BIR), structural incomplete response (SIR), or indeterminate response (IDR). Gender, age at diagnosis, pathological type, stages (TNM), stimulated thyroglobulin (sTg) value before initial 131I treatment, metastatic nodule size, and type of post-treatment whole body scan (Rx-WBS) were recorded. Mono-factor analysis and binary logistic regression analyses were used to identify the factors that might affect the ER in DTC pulmonary metastases. The receiver operating characteristic (ROC) curve of the sTg value was used to predict the ER of 131I treatment. ResultsAll 75 patients with exclusively 131I-avid pulmonary metastases received 131I treatment and underwent follow-up. Out of the 75 patients, 26 achieved ER, resulting in an excellent response rate of 34.7 % (26/75). Among them, 25 (25/26, 96.2 %) achieved an ER after undergoing two rounds of 131I treatment. Binary logistic regression analysis showed that the factors influencing DTC pulmonary metastases excellent response were lower sTg levels [odds ratio (OR) = 0.998, P < 0.001], micronodular metastases (OR = 0.349, P = 0.001) and focal distribution on Rx-WBS imaging (OR = 0.113, P = 0.001). The area under the ROC curve for sTg value predicting ER was 0.876, and the cut-off value was 26.84 ng/mL, with a sensitivity and specificity of 87.9 % and 80.3 %, respectively. Conclusions131I treatment is effective for 131I-avid pulmonary metastases of DTC. Some patients who underwent 131I treatment achieved ER. Most patients with ER were obtained after two rounds of 131I treatments. Patients with sTg values before initial 131I treatment lower than 26.84 ng/mL, micronodular metastases, and focal distribution on Rx-WBS imaging were more likely to achieve ER.

SAT530 Use of Tamoxifen and Cabergoline to Suppress Breast Tissue Uptake of Radioactive Iodine Among Differentiated Thyroid Cancer Patients

Abstract Disclosure: A.H. Mohamed: None. M. Basina: None. Background: Radioactive iodine (RAI) has been used in thyroid cancer treatment. Physiologic breast tissue uptake and accumulation of RAI are not desirable due to increased carcinogenesis risk. Case1:31 years old non lactating female diagnosed with stage IVB papillary thyroid cancer and underwent total thyroidectomy and bilateral neck dissection. She had high initial risk with stage of T3N1bM1 and underwent 118 mCi of I-131 treatment with pulmonary foci. One year later, she had biochemical and structural incomplete response and underwent I-123 RAI uptake scan demonstrating residual disease in the right neck and diffuse breast uptake, thus, I-131 treatment was deferred. The patient was started on cabergoline 0.5 mg daily for 2 months. Repeated I-123 uptake scan during day 2 of Cabergoline remained with diffuse breast uptake. Four months later, another repeated RAI uptake scan after 4 months showed minimal breast uptake and RAI I-131 treatment was given. She had normal mammogram screening. Case2: 41 years old non lactating female diagnosed with stage II papillary thyroid cancer and underwent total thyroidectomy with right neck dissection. She had moderate initial risk with stage of T3 N1aM0 and underwent 159 mCI of I-131 treatment. Two years later, she had structural incomplete response and repeated I-123 uptake scan showed thyroid bed foci of avid uptake and diffuse bilateral breast uptake, thus, I-131 therapy was deferred. The patient was started on cabergoline 0.25 mg daily for 4 weeks and Tamoxifen 10 mg twice daily for 10 days prior to repeated I-123 RAI scan that redemonstrated thyroid bed foci without breast tissue uptake. She had normal mammogram screening. DiscussionPotential malignancy risk secondary to non-thyroidal RAI accumulation in tissues was reported. The mechanism of breast RAI uptake involves Na/iodide symporter channel regulated by prolactin and estrogen. Blocking the effect of these hormones prior to I-131 administration are believed to prevent breast uptake. We describe two papillary thyroid cancer cases with breast RAI uptake that was suppressed partially with Cabergoline (prolactin lowering agent) and fully with combination of Cabergoline and Tamoxifen (estrogen receptor blocker). Further studies are needed to evaluate the efficacy of Tamoxifen and cabergoline in suppressing physiologic breast RAI uptake. Presentation Date: Saturday, June 17, 2023

Usefulness of second 131I treatment in biochemical persistent differentiated thyroid cancer patients.

Second 131I treatment is commonly performed in clinical practice in patients with differentiated thyroid cancer and biochemical incomplete or indeterminate response (BiR/InR) after initial treatment. The objective of the is study is to evaluate the clinical impact of the second 131I treatment in BiR/InR patients and analyze the predictive factors for structural incomplete response (SiR). One hundred fifty-three BiR/InR patients after initial treatment who received a second 131I treatment were included in the study. The clinical response in a short- and medium- long-term follow-up was evaluated. After the second 131I treatment (median 8 months), 11.8% patients showed excellent response (ER), 17% SiR, while BiR/InR persisted in 71.2%. Less than half (38.5%) of SiR patients had radioiodine-avid metastases. Patients who, following the second 131I treatment, experienced SiR had larger tumor size and more frequently aggressive histology and vascular invasion than those experienced BiR/InR and ER. Also, the median values of thyroglobulin on levothyroxine therapy (LT4-Tg), Tg peak after recombinant human TSH stimulation (rhTSH-Tg) and thyroglobulin antibodies (TgAb) were significantly higher in patients who developed SiR. At last evaluation (median: 9.9 years), BiR/InR persisted in 57.5%, while 26.2% and 16.3% of the patients showed ER and SiR, respectively. About half of BiR/InR patients (71/153 (46.4%)) received further treatments after the second 131I treatment. Radioiodine-avid metastatic disease detected by the second 131I is an infrequent finding in patients with BiR/InR after initial treatment. However, specific pathologic and biochemical features allow to better identify those cases with higher probability of developing SiR, thus improving the clinical effectiveness of performing a second 131I treatment.

Dynamic Risk Stratification Integrated with ATA Risk System for Predicting Long-Term Outcome in Papillary Thyroid Cancer.

In recent years, there has been a renewed interest in thyroid cancer management paradigms that use individualized risk assessments as the basis for treatment and follow-up recommendations. In this study, we assumed that the long-term follow-up of differentiated thyroid cancer patients might be better tailored by integrating the response to initial therapy with the America Thyroid Association (ATA) risk classes. This retrospective study included low- and intermediate-risk papillary thyroid cancer (PTC) patients followed up for a median time of 8 years and classified according to the response to initial therapy assessed 6-12 months after initial treatment. After a median follow-up of 8 years, in the initial excellent response subgroup of PTC patients (n = 522), the rate of recurrent disease was significantly higher in intermediate-risk patients than in low-risk PTC patients (6.9% versus 1.2%, p = 0.0005). Similarly, in the initial biochemical incomplete response subgroup (n = 82), the rate of excellent response was significantly higher in low-risk PTC patients (58.0%) than in intermediate-risk PTC patients (33.3%) (p = 0.007). Finally, in the initial structural incomplete response subgroup (n = 66), the rate of excellent response was higher in low-risk patients (80.0%) than in intermediate-risk patients (46.4%) (p = 0.08). Moreover, all patients with initial indeterminate response had an excellent response at the last follow-up visit. ATA risk classes were independently associated with long-term outcome in each subgroup of patients classified dynamically after initial therapy and the overall prognostic performance, defined via ROC curve analysis, of response to initial therapy integrated with the ATA risk system (AUC: 0.89; 95% CI: 0.86-0.92) was significantly higher compared to the ATA risk stratification (AUC 0.69; 95% CI: 0.65-0.74, p < 0.001) or the dynamic risk stratification (DRS) systems alone (AUC: 0.86 95% CI: 0.82-0.90, p = 0.007). This study of a large cohort of PTC patients showed that the initial ATA risk criteria may be useful for improving the risk-adapted management of PTC patients based on the response to initial therapy.

Comparison of Prognostic Value Between Stimulated and Nonstimulated Thyroglobulins in Differentiated Thyroid Cancer: A Retrospective Study.

The growing incidence of differentiated thyroid cancer (DTC) demands dependable prognostic factors to guide follow-up and treatment plans. This study investigated the prognostic value of response to therapy (RTT) assessment using TSH stimulated-thyroglobulin (sti-Tg) and nonstimulated-thyroglobulin (nonsti-Tg) and evaluates whether RTT using nonsti-Tg (nonstiRTT) can replace RTT using sti-Tg (stiRTT) in clinical practice to improve patients' quality of life during assessment. We enrolled 419 DTC patients who underwent total thyroidectomy, radioactive iodine (RAI) therapy, and Tg assessment. Patients with structural incomplete responses were excluded. Initial RTT assessments based on the 2015 American Thyroid Association guidelines (excellent response; ER, indeterminate response, biochemical incomplete response) were performed 6-24months after RAI therapy. The second RTT assessments were performed 6-24months after the first assessment. Statistical analysis for recurrence-free survival (RFS) was done with the log-rank test for stiRTT and nonstiRTT. Although initial stiRTT and nonstiRTT were significant predictors for RFS (p < 0.0001), stiRTT provided better RFS prediction than nonstiRTT. The RFS analysis of the second RTT assessment demonstrated statistical significance only for stiRTT (p < 0.0001). In 116 patients classified as ER on initial stiRTT, there was no RFS difference between patients classified as ER on either second stiRTT or nonstiRTT. The prognostic power of stiRTT surpasses that of nonstiRTT in both the initial and second RTT assessment. Nevertheless, among patients classified as ER on initial stiRTT, a second stiRTT may not be required for those classified as ER on the second nonstiRTT. The online version contains supplementary material available at 10.1007/s13139-023-00811-8.

Utilizing Dynamic Risk Stratification in Patients With Tall Cell Variant Papillary Thyroid Cancer.

Tall cell variant (TCV) papillary thyroid cancer (PTC) is a subtype of PTC associated with aggressive tumor behavior, advanced stage, and higher rates of recurrence and mortality. The present study aimed to test an established dynamic risk stratification tool in the TCV population, with the goal of better predicting the postoperative course of these patients. Retrospective chart review. A total of 94 patients with TCV who underwent total thyroidectomy with radioactive iodine ablation were retrospectively reviewed from 1998 through 2020. Biochemical, structural, and overall response to treatment was determined for each patient, based on postoperative thyroglobulin levels and imaging findings. Primary outcomes were locoregional and distant recurrence, presence of disease at final follow-up, need for additional intervention, and disease-specific mortality. Patients with TCV who were stratified as having an excellent overall response to treatment had lower rates of locoregional recurrence than indeterminate, biochemical incomplete, and structural incomplete responses (2.0%, 33.3%, 55.0%, and 85.7% at 5 years respectively, p < 0.001). The same was true for distant recurrence as well (2.0%, 9.0%, 35.1%, and 42.9%, p < 0.001). An excellent response was also associated with lower rates of presence of disease at final follow-up, need for additional intervention, and disease-specific mortality. Although TCV is an aggressive subtype associated with worse clinical outcomes than classical PTC, patients with an excellent overall response to treatment have significantly improved outcomes when compared to indeterminate, biochemical incomplete, and structural incomplete responses. 3 Laryngoscope, 133:2430-2438, 2023.