Thyroglobulin as early prognostic marker to predict remission at 18-24 months in differentiated thyroid carcinoma

Clinical Role of Pre-ablation Stimulated Thyroglobulin and Thyroid-Stimulating Hormone Ratio for Radioactive Iodine Treatment in Adults with Papillary Thyroid Cancer

OBJECTIVE

This investigation assesses the predictive utility of the pre-ablation stimulated thyroglobulin to thyroid-stimulating hormone ratio (sTg/TSH) and examines the other factors affecting the efficacy of radioactive iodine (RAI) therapy in adult patients with papillary thyroid cancer (PTC).

METHODS

We performed a retrospective review of clinical and pathological data from 1071 patients who received a total thyroidectomy followed by RAI therapy. The study included 576 of these patients. Participants were separated into two groups according to their reaction to RAI therapy: excellent response (ER) and non-ER (NER). The factors that contribute to NER were found using univariate and multivariate binary logistic regression analyses. The predictive importance of the sTg and sTg/TSH ratio was discovered by analyzing receiver operating characteristic (ROC) curves and setting diagnostic criteria. Decision curve analysis (DCA) was used to assess the practical implications of these findings.

RESULTS

Among the 576 patients assessed, 60.07% (346 individuals) demonstrated an ER to RAI treatment. Independent predictors of a NER identified through both univariate and multivariate logistic regression analyses included multifocality (odds ratio [OR] = 2.16, 95% confidence interval [CI]: 1.28-3.67, P = 0.004), having more than ten positive lymph nodes (PLN) (OR = 3.78, 95% CI: 1.68-8.54, P = 0.001), presence of distant metastases (OR = 19.22, 95% CI: 2.09-176.93, P = 0.009), elevated stimulated thyroglobulin (sTg) levels (OR = 1.04, 95% CI: 1.00-1.07, P = 0.025), and a higher sTg/TSH ratio (OR = 2.48, 95% CI: 1.80-3.41, P < 0.001). Receiver operating characteristic (ROC) curve analysis established diagnostic thresholds for predicting NER at an sTg level of 7.255 ng/ml (area under the curve [AUC] = 0.893) and an sTg/TSH ratio of 0.127 (AUC = 0.889), both demonstrating robust sensitivity and specificity. Smooth curve fitting illustrated a progressive increase in the risk of NER with rising levels of the sTg/TSH ratio. DCA confirmed the substantial clinical net benefit of these predictors in forecasting NER outcomes.

CONCLUSIONS

The sTg/TSH ratio is confirmed as a reliable diagnostic marker for predicting the response to primary RAI treatment in PTC. Moreover, active postoperative follow-up and surveillance are essential for patients with multifocality, PLN >10, sTg >7.255 ng/ml, and sTg/TSH ratio >0.127.

A deep dive into four thyroglobulin immunoassays from analytical perspective

BACKGROUNDS

Serum thyroglobulin immunometric assays (sTg) are crucial for monitoring differentiated thyroid cancer (DTC) treatment. However, challenges such as anti-thyroglobulin autoantibodies (TgAb) and assay variability hinder evaluations. This study assessed four sTg methods-three second-generation (Architect, Access, Elecsys) and one first-generation (Immulite)-following Clinical and Laboratory Standards Institute (CLSI) and American Thyroid Association (ATA) guidelines.

METHODS

The study compared sTg(Architect), sTg(Access), sTg(Elecsys), and sTg(Immulite). Precision was evaluated per CLSI EP05-A3, while the lower limits of detection (LLD) were assessed using EP17-A2. Passing-Bablok and Bland-Altman analyses were conducted as per EP09c, and semi-quantitative comparisons used Kappa statistics.

RESULTS

The second-generation sTgs (Architect, Access, Elecsys) exhibited satisfactory precision (<7% coefficient of variation, CV%), unlike sTg(Immulite), which showed significant deviations and inadequate sensitivity for DTC recurrence (Limit of quantitation, LoQ = 4.59 μg/L). Second-generation sTgs had strong correlations (r > 0.884) across all concentration ranges (≤1, 1-10, >10 μg/L), with biases (slope: 1.131-2.027). sTg(Immulite) correlated well with second-generation methods for concentrations >10 μg/L (r > 0.945) but less so for <10 μg/L (r < 0.642). TgAb significantly impacted sTg(Immulite). Kappa statistics revealed strong agreement among second-generation methods (κ > 0.800) but lower concordance with sTg(Immulite), especially in TgAb(+) samples (κ: 0.562-0.653). Agreement ratios were high for second-generation methods (0.667-1.000) but variable for sTg(Immulite), particularly at lower concentrations and in TgAb(+) cases (0.097-0.727).

CONCLUSIONS

sTg(Immulite) did not meet LLD and precision criteria for DTC monitoring, facing issues with TgAb interference. Second-generation sTgs demonstrated consistent performance across all concentrations.

Aggressive variants of papillary thyroid carcinoma: characteristics, influencing factors, and effectiveness of radioiodine therapy

PURPOSE

To investigate the pathological characteristics of aggressive variants of papillary thyroid carcinoma (PTC) and evaluate the efficacy of radioiodine (RAI) therapy for these variants.

METHODS

We analysed 129 patients with aggressive variants of PTC and compared them to those of 4460 patients with non-aggressive variants. And we examined the efficacy of RAI therapy in 70 eligible patients with aggressive variants of PTC and 2530 eligible patients with non-aggressive variants of PTC.

RESULTS

Aggressive and non-aggressive variants of PTC demonstrated a greater degree of variability in terms of age, multifocality, capsular invasion, vascular invasion, extrathyroidal invasion, lymph node metastases, disease stage, risk stratification, N stage, comorbid with Hashimoto thyroiditis (HT) and comorbid with nodular goiter (NG). Propensity score matching method showed poor efficacy of RAI treatment in patients with aggressive variants of PTC compared with non-aggressive variants. Multifactorial analysis showed that comorbid NG was an independent risk factor for poor effectiveness of RAI treatment for aggressive PTC variants ((hazard ratio (HR) 3.027; 95% confidence interval (CI), 1.295-7.075).

CONCLUSION

Aggressive variants of PTC demonstrated a higher degree of aggressiveness and poor efficacy of RAI therapy compared to non-aggressive variants, especially comorbid with NG, which may require higher therapeutic 131I dosage.

Is Stimulated Thyroglobulin Before Radioiodine Therapy a Useful Tool in Predicting Response to Initial Therapy in Patients with Differentiated Thyroid Carcinoma?

Thyroglobulin (Tg) is an important tool to evaluate the persistence and recurrence risk in differentiated thyroid cancer (DTC). We aimed to evaluate the correlation between pre-radioiodine therapy stimulated Tg (pre-RAI Tg) levels and the first response to treatment evaluation, and to establish a cut-off pre-RAI Tg threshold for predicting an initial excellent response. Retrospective cohort study of DTC patients who underwent total thyroidectomy and radioiodine therapy. Response to therapy was evaluated 6 to 24 months after initial therapy, and patients were classified as: excellent response (ER); indeterminate response (IndR) and incomplete response (IncR). Total patients: 166 among which 85.5% female with mean age of 47.6 ± 13 years. The ER had a significantly lower pre-RAI Tg in comparison to IndR (p<0.001) and IncR (p<0.001), and pre-RAI Tg were different between the IndR and IncR (p=0.02). A cut-off pre-RAI Tg value at 7.55ng/ml was obtained by receiver operating characteristics curve for differentiating ER from IndR and IncR. The area under curve was 0.832 (95% CI 0.76-0.91). In multivariate analysis, ATA low-risk (RR 1.61, 95% CI 1.06-2.43, p=0.025) and Tg below 7.55ng/ml (RR 2.17, 95% CI 1.52-3.10, p<0.001) were associated with ER. After a median of 7.4-year follow-up, 124 (74.7%) patients were allocated into ER, 22 (13.2%) into IndR, and 20 (12%) into IncR. In conclusion, pre-RAI Tg predicts first evaluation of treatment response. Pre-RAI Tg cut-off was a key predictor of initial excellent response to therapy and may be an important tool in the follow-up of DTC patients.

Clinicopathological features affecting the efficacy in 131I ablation therapy of papillary thyroid carcinoma with lymph node metastasis

Background

Lymph node metastasis is the major cause of increased recurrence and death in patients with papillary thyroid carcinoma (PTC). We evaluate the clinicopathologic factors affecting excellent response (ER) in patients with PTC with lymph node metastasis following operation and 131I ablation therapy.

Methods

A total of 423 patients with PTC with lymph node metastasis who underwent thyroidectomy and postoperative 131I ablation therapy were enrolled. The relationship between clinicopathological factors affecting ER achievement was analyzed.

Results

Multivariate analysis showed that the foci diameter (≤1 cm), unifocal, combination with Hashimoto's thyroiditis (HT), lymph node metastases rate (LR) (≤40%), no postoperative lymph node metastasis, low preablative stimulated thyroglobulin (ps-Tg) level (≤3.87 ng/mL), and the time of 131I ablation therapy (one time) were positively correlated with the ER achievement [odds ratio (OR): 1.744, 3.114, 3.920, 4.018, 2.074, 9.767, and 49.491, respectively; all p < 0.05]. The receiver operating characteristic (ROC) curves showed that the cutoff values of ps-Tg and LR were 4.625 ng/mL and 50.50%, respectively. The AUC of ROC of ps-Tg and LR for predicting ER achievement was 0.821 and 0.746, respectively. The Tg and the cumulative risk of non-ER elevated with the increase of LR, especially for the high-level ps-Tg (>4.625 ng/mL) group.

Conclusion

The foci diameter and number, combination with HT, LR, and ps-Tg level are independent factors for ER. Ps-Tg level and LR are valid predictive factors for the efficacy of 131I therapy in patients with PTC. The predictive value of the cumulative risk of non-ER can be improved by the combination of ps-Tg and LR.

Comparing High and Low-Dose Radio-Iodine Therapy in Thyroid Remnant Ablation Among Intermediate and Low-Risk Papillary Thyroid Carcinoma Patients-Single Centre Experience

The role of Iodine-131 therapy is well established as an adjuvant therapy and for thyroid remnant ablation in differentiated thyroid cancer (DTC); however controversy still exists regarding its appropriate dose. Purpose of this study was to compare the effectiveness of low-dose and high-dose Iodine-131 ablation therapies in low- and intermediate-risk PTC patients. Eighty-four patients were divided equally into Group I: Ablated with high dose of Iodine-131 and Group II: Ablated with low dose of Iodine-131. Iodine-131 WBS, serum TG levels and USG neck of all patients were performed at first presentation, 6 months, 1 year, and 2 years follow up. Results are as follows: Group I: 64%, 72%, and 76% intermediate-risk patients were disease free at the follow up intervals of 6 months, 1 year, and 2 years, respectively. Similarly 70%, 82%, and 82% low-risk patients were disease free at above mentioned intervals. Group II: 56%, 60%, and 64% were disease free among intermediate-risk patients while percentage of disease free low-risk patients was 70%, 76%, and 76% at follow up intervals. Low dose of radioactive Iodine-131 was found as effective as high dose in thyroid remnant ablation of PTC patients.

Analysis of factors influencing the clinical outcome after surgery and 131I therapy in patients with moderate-risk thyroid papillary carcinoma

PURPOSE

Generally, the prognosis for papillary thyroid cancer (PTC) is favorable. However, the moderate risk involved warrants further evaluation. Hence, we investigated the clinical outcomes in patients with moderate-risk PTC following surgery and the first ¹³¹I therapy, as well as the relevant factors that influence the therapeutic efficacy.

METHODS

Retrospective analyses of 175 patients with medium-risk PTC who visited the Second Affiliated Hospital of Chongqing Medical University from September 2017 to April 2019 were conducted. In according with the 2015 American Thyroid Association (ATA) guideline treatment response evaluation system, the patients were categorized into the following groups: excellent response (ER), indeterminate response (IDR), biochemical incomplete response (BIR), and structurally incomplete response (SIR), of which IDR, BIR, and SIR were collectively referred to as the NER group. To compare the general clinical features between the 2 groups of patients, 2 independent samples t-tests, χ² test, and Mann-Whitney U-test were performed, followed by multivariate logistic regression analyses. With reference to the receiver operating characteristic (ROC) curve, the predicted value of ps-Tg to ER was evaluated, and the best cut-off value was determined. The subgroups with BRAF^V600E test results were analyzed by χ2 test only.

RESULTS

The treatment responses of 123 patients were ER, while those of 52 patients were NER. The differences in the maximum tumor diameter (U = 2495.50), the amount of metastatic lymph nodes (U = 2313.50), the size of metastatic lymph node (U = 2113.50), the metastatic lymph node ratio (U = 2111.50), metastatic lymph node location (χ² = 9.20), and ps-Tg level (U = 1011.00) were statistically significant. Multivariate regression analysis revealed that ps-Tg (OR = 1.209, 95% CI: 1.120-1.305) was an independent variable affecting ER. The cut-off value of ps-Tg for predicting ER was 6.915 ug/L, while its sensitivity and specificity were 69.2% and 89.4%, respectively.

CONCLUSIONS

Patients with smaller tumor size, fewer lymph nodes, lower metastatic lymph node ratio, metastatic lymph nodes in the central region, smaller lymph node size, and ps-Tg <6.915 ug/L demonstrated better therapeutic effects after the initial treatment.

Combination of Stimulated Thyroglobulin and Antithyroglobulin Antibody Predicts the Efficacy and Prognosis of 131I Therapy in Patients With Differentiated Thyroid Cancer Following Total Thyroidectomy: A Retrospective Study

BACKGROUND AND PURPOSE

This study aimed to analyze the diagnostic ability of the combination of stimulated thyroglobulin (sTg) and antithyroglobulin antibody (TgAb) in predicting the efficacy and prognosis of radioactive iodine (¹³¹I) therapy (RAIT) in patients with differentiated thyroid carcinomas (DTCs) after total thyroidectomy (TT).

METHODS

This retrospective study comprised 409 DTC patients who underwent ¹³¹I treatment following TT in the First Affiliated Hospital of Zhengzhou University from January 2019 to August 2020, and they were followed up to November 2021. Patients were divided into the successful ablation and the unsuccessful ablation group based on the classification of the efficacy of RAIT in the 2015 American Thyroid Association guidelines. The clinical characteristics and the efficacy of the initial RAIT were evaluated. The cutoffs of preablation sTg, sTg/thyroid-stimulating hormone (TSH) ratio, and sTg×TgAb product were calculated to predict the efficacy of RAIT. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors for unsuccessful ablation. Kaplan-Meier curves were used to estimate the prognostic value of sTg×TgAb product affecting progression-free survival (PFS).

RESULTS

The cohort consisted of 222 cases in the successful ablation group and 187 cases in the unsuccessful ablation group. Between the two groups, preablation sTg, sTg/TSH ratio, and sTg×TgAb product were significantly higher in the unsuccessful ablation group. The area under the curve (AUC) of the sTg×TgAb product was the highest among the above three factors. The cutoffs for the worse therapeutic effect of the initial RAIT in sTg, sTg/TSH ratio, and sTg×TgAb were >2.99 ng/ml, >0.029 mg/IU, and >34.18, respectively. STg >2.99 ng/ml and sTg×TgAb product >34.18 were independent risk factors for unsuccessful ablation. Patients with sTg×TgAb product >34.18 had shorter PFS than that of patients with sTg×TgAb product ≤34.18. In separate analyses of TgAb-negative and TgAb-positive subgroups, higher sTg×TgAb was both associated with a lower success rate of RAIT and a shorter PFS.

CONCLUSION

STg×TgAb product predicted the efficacy and prognosis of ¹³¹I therapy for both TgAb-negative and TgAb-positive DTC patients before the initial ¹³¹I treatment following TT. Thus, it can be used as a clinical reference indicator for the surveillance of DTC patients.

Analysis of Curative Effect and Influencing Factors of N1 Stage Papillary Thyroid Micro-Carcinoma and Papillary Thyroid Non-Micro Carcinoma After Initial Radioactive Iodine Ablation Therapy

Objective

To compare the efficacy and influencing factors of initial radioactive iodine (RAI) ablation therapy for postoperative N1 stage papillary thyroid micro-carcinoma (PTMC) and papillary thyroid non-micro carcinoma (PTC), and to explore the necessity of RAI for N1 stage PTMC.

Methods

A retrospective analysis of patients with N1 stage papillary thyroid cancer who underwent RAI in our department from January 2018 to June 2019. According to the tumor diameter, papillary thyroid carcinoma was divided into PTMC group (≤ 1.0cm) with 129 patients and PTC group (> 1.0 cm) with 214 patients. According to the 2015 ATA guidelines, the patient’s treatment response was evaluated 6–8 months after discharge from the hospital: excellent response (ER), indeterminate response (IDR), biochemical incomplete response (BIR), and structural incomplete response (SIR). IDR, BIR, and SIR were classified into NER group. Chi-squared test, independent sample t-test, Mann–Whitney U test, and binary logistic regression analysis were used to compare the differences between PTMC and PTC patients.

Results

The ps-Tg of the PTMC group was significantly lower than that of the PTC group (P = 0.001), and the ER ratio of the PTMC group was higher (χ² = 5.445, P < 0.05). The ER ratio of PTMC patients in the N1a group was significantly higher than that of PTC patients (80%, 66.7%, χ² = 4.076, P < 0.05), while the ER ratio of PTMC in the N1b group was not significantly different from that of PTC. Gender, N stage, and ps-Tg were found to be independent factors of RAI treatment response.

Conclusion

The efficacy of the initial RAI of PTMC patients was significantly better than that of PTC patients. There was no significant difference in the efficacy of RAI between males with PTMC, N1b stage, ps-Tg ≥ 5.87ng/mL and PTC patients, which suggested that RAI is necessary for these patients.

The Influences of TSH Stimulation Level, Stimulated Tg Level and Tg/TSH Ratio on the Therapeutic Effect of 131I Treatment in DTC Patients

PURPOSE

To study the influences of pre-ablation TSH stimulation level, sTg and sTg/TSH ratio on the therapeutic effect of the first ¹³¹I treatment in DTCs.

METHODS

According to the thyroid stimulating hormone (TSH) levels (mU/l), all the 479 differentiated thyroid cancer (DTC) patients were divided into two groups: TSH < 30 and TSH ≥ 30. The TSH ≥ 30 group was divided into three subgroups: 30 ≤ TSH < 60, 60 ≤ TSH < 90 and TSH ≥ 90. The clinical features and the therapeutic effects of the first ¹³¹I treatment were analyzed. The cutoffs of stimulated thyroglobulin (sTg) and sTg/TSH ratio were calculated to predict the therapeutic effect of ¹³¹I treatment.

RESULTS

Among the three subgroups, the TSH ≥ 90 subgroup was younger and less likely to be associated with cervical lymph node metastasis (LNM). The postoperative levothyroxine (L-T₄) dose in the 60 ≤ TSH < 90 subgroup was the lowest. Between the two groups, patients in the TSH < 30 group had higher postoperative L-T₄ dose and longer thyroid hormone withdrawal (THW) time. The excellent response rates six months after the first ¹³¹I treatment among the three subgroups and between the two groups were not of statistical significance. The distribution of different TSH stimulation levels among each response group was similar. The cutoffs for the better therapeutic effect of the first ¹³¹I treatment in sTg and sTg/TSH were < 9.51 ng/ml and < 0.11, respectively. Both univariate and multivariate logistic regressions showed that cervical LNM, distant metastasis, higher sTg and higher sTg/TSH ratio predicted poorer therapeutic effect.

CONCLUSIONS

There was no significant influence of TSH stimulation levels before the first ¹³¹I treatment on the therapeutic effect of DTC. The sTg/TSH ratio can be considered as another predictor of ¹³¹I therapeutic effect.

A retrospective study of the risk factors and the prognosis in patients with papillary thyroid carcinoma depending on the number of lymph node metastasis

To retrospectively analyze the risk factors and the prognosis according to the number of lymph node metastases (LNMs) in different neck compartments in papillary thyroid carcinoma (PTC) patients. In total, 962 patients with PTC were enrolled in this study. According to the methods of the 2015 American Thyroid Association, the treatment response of the patients was divided into a good prognosis and a poor prognosis. First, their clinical characteristics were summarized. Then, according to whether they had LNMs and the number of LNMs in different neck compartments, their risk factors and their prognosis were analyzed. Male sex, younger (< 45 years), extrathyroid extension (ETE), T₁ staging and higher stimulated thyroglobulin (sTg) levels were the risk factors for LNM. The cutoff for a poor prognosis of the number of LNMs was > 4. Male sex, younger age, higher sTg levels and ETE were correlated with LNM > 4. Furthermore, the cutoffs for a poor prognosis of central lymph node metastasis (CLNM), lateral lymph node metastasis (LLNM) and CLNM + LLNM were > 6, > 1 and > 5, respectively. Younger age and ETE were strongly correlated with CLNM > 6. Male sex, younger age, higher sTg levels and ETE were correlated with LLNM > 1. Younger age, ETE and higher sTg levels were correlated with CLNM + LLNM > 5. Further analysis revealed a positive correlation between CLNM and LLNM. We should pay more attention to LNMs in PTC patients who are male, are of a younger age, have ETE, T₁ staging and have higher sTg levels. The neck regional LNMs should be correctly evaluated to guide the surgical options for the neck LNMs in PTC. When the number of LNMs in different neck compartments has exceeded the cutoff value, they can be considered as predictors of the outcome of ¹³¹I treatment.

Efficacy and Affecting Factors of 131I Thyroid Remnant Ablation After Surgical Treatment of Differentiated Thyroid Carcinoma

Purpose: Radioiodine (¹³¹I) thyroid remnant ablation is an important treatment of differentiated thyroid carcinoma (DTC) and various factors affecting its efficacy have been reported but not well defined. The aim of our study was to evaluate the efficacy and the affecting factors of ¹³¹I ablation after total or near-total thyroidectomy in a relative large DTC cohort. Methods: 261 DTC patients with negative thyroglobulin antibody received 100-200 mCi ¹³¹I for thyroid remnant ablation after total or near-total thyroidectomy between January 2012 and October 2015 in our hospital. The efficacy and affecting factors of ¹³¹I ablation therapy were retrospectively investigated. Results: The success rate of the first ¹³¹I thyroid remnant ablation was 65.90%. Univariate analysis demonstrated that larger tumor size, higher level of pre-ablation stimulated thyroglobulin (sTg), intermediate to high risk stratification for recurrence, and lymph node and distant metastases were associated with a lower success rate of the first ¹³¹I ablation (all p < 0.05). Multivariate logistic regression analysis showed that tumor size, pre-ablation sTg, and lymph node and distant metastases were independent factors affecting the efficacy of the first ¹³¹I ablation. Areas under receiver operating characteristic curves for sTg, sTg/TSH ratio, and tumor size to predict unsuccessful ablation were 0.831, 0.824, and 0.648, respectively. The threshold values were 4.595 ng/ml, 0.046 mg/IU, and 1.350 cm, respectively. The sensitivities were 95.51, 96.63, and 73.03% and the specificities were 64.54, 61.63, and 49.41%, respectively. The excellent response (ER) ratio of the successful group was significantly higher than that of the unsuccessful group. Conclusions: The efficacy of the first ¹³¹I thyroid remnant ablation after surgical treatment of DTC is well demonstrated, and tumor size, pre-ablation sTg, lymph node, and distant metastases are independent factors affecting its efficacy.

Thyroglobulin levels and thyroglobulin/thyrotropin ratio could predict the success of the ablative/therapeutic 131I in the differentiated thyroid cancers

BACKGROUND

Stimulated thyroglobulin (STg) levels in patients with differentiated thyroid carcinomas (DTCs) after total thyroidectomy (TT) and before radioactive iodine (¹³¹I) ablation/therapy (RIT) are predictive of therapeutic success but can be influenced by the thyroid-stimulating hormone (TSH) level.

OBJECTIVES

This study compared the reliability of the STg/TSH ratio and STg measurement in predicting the success of RIT.

METHODS

Sixty-three DTC patients submitted to TT were assessed retrospectively to compare the ability of STg level and the STg/TSH ratio to predict successful RIT.

RESULTS

In this study 48 (76.2%) patients had successful RIT. The successful and unsuccessful groups received different ¹³¹I doses and had different STg levels and STg/TSH ratios. The STg and STg/TSH ratio cutoff values that predicted successful RIT were 4.41 ng/mL (sensitivity of 86.7% and specificity of 77%) and 0.093 (sensitivity of 80% and specificity of 79.2%), respectively. Age, STg level, STg/TSH ratio, and ¹³¹I dose were associated with successful RIT, but after multivariate analysis only STg remained associated (p < 0.05).

CONCLUSION

In conclusion, our data suggest that the STg/TSH ratio and measurement of STg are equally reliable in predicting successful RIT in DTC patients.

In Patients With Low- to Intermediate-Risk Thyroid Cancer, a Preablative Thyrotropin Level of 30 μIU/mL Is Not Adequate to Achieve Better Response to 131I Therapy

PURPOSE

The optimal preablative level of thyrotropin (TSH) for patients with differentiated thyroid cancer (DTC) to achieve better response after I ablation remains unknown. The objective of this study was to assess whether a higher preablative TSH level above 30 μIU/mL is associated with better response to I therapy in low- to intermediate-risk DTC and to explore the potential factors that may impact their responses.

PATIENTS AND METHODS

A total of 204 consecutive non-high-risk patients were retrospectively reviewed. Serum TSH and thyroglobulin (Tg) levels were measured right before I treatment after thyroxine hormone withdrawal (THW). Patients were categorized by their preablative TSH level grouping of 30 to less than 60 (n = 11), 60 to less than 90 (n = 61), 90 to less than 120 (n = 56), 120 to less than 150 (n = 33), and 150 μIU/mL or greater (n = 43). Responses to I therapy were evaluated as excellent, indeterminate, biochemical incomplete, or structural incomplete response (ER, IDR, BIR, or SIR) after a mean follow-up of 20.3 months. Initial risk factors (age, sex, T and N status by AJCC/UICC TNM staging system, and thyroid remnant), the administered dose of I and response to I therapy were compared among different preablative TSH groups. Multivariate analysis was further performed to identify factors associated with incomplete response (IR, including BIR and SIR).

RESULTS

Except the significant correlation between younger age and higher preablative TSH level (P = 0.001), the 5 TSH groups did not differ in other related prognostic factors or dose of I (all P > 0.05). Among each ascending TSH group, ER was observed in 54.5%, 68.9%, 73.2%, 69.7%, and 60.5%, respectively, whereas IR was observed in 18.2%, 18.0%, 7.1%, 9.1%, and 20.9%, respectively. Group 90 to less than 120 μIU/mL presented the highest rate of ER and lowest rate of IR. In the multivariate analysis, preablative TSH level, in addition to preablative Tg, was also an associated factor for response to I therapy (P = 0.048).

CONCLUSIONS

A preablative TSH level of 90 to less than 120 μIU/mL might be more appropriate for patients with low- to intermediate-risk DTC to achieve better response to I therapy.

Serial stimulated thyroglobulin measurements are more specific for detecting distant metastatic differentiated thyroid cancer before radioiodine therapy

OBJECTIVE

Preablative stimulated thyroglobulin (ps-Tg) has the potential to be used in identifying distant metastatic differentiated thyroid carcinoma (DM-DTC), but its single level can be affected by remnant thyroid tissue and thyrotropin (TSH). The objective of this retrospective study was to evaluate the value of serial ps-Tg measurements in identifying DM-DTC specifically.

METHODS

A total of 317 DTC patients with serial measurements of ps-Tg, TSH and anti-Tg antibody were divided into M1 (n=72) and M0 (n=245) according to the presence of distant metastasis (DM) or not. The initial ps-Tg measurement, with a corresponding TSH exceeding 30 μIU/mL, was marked as Tg1, and ps-Tg measured right before radioactive iodine (RAI) therapy was defined as Tg2, with a median interval of 8 days. ΔTg denotes Tg2-Tg1, and ΔTSH denotes TSH2-TSH1. Tg1, Tg2, ΔTg, and ΔTg/ΔTSH were tested for efficacy in identifying DM-DTC using receiver operating characteristic (ROC) curve analysis, and further compared with chest computed tomography (CT) and posttreatment whole-body RAI scan (RxWBS).

RESULTS

Compared with single ps-Tg measurement (Tg1 or Tg2), both ΔTg and ΔTg/ΔTSH were more narrowly distributed around zero in the M0 group, which made their distribution in the M1 group more distinguished in a relatively dispersed way. ΔTg/ΔTSH manifested a higher accuracy (88.64%) and specificity (90.20%) in identifying DM-DTC than Tg1 or Tg2 measurements, with a much higher specificity than chest CT (90.20% vs. 66.00%) and a much higher sensitivity than RxWBS (83.33% vs. 61.11%).

CONCLUSIONS

Serial ps-Tg measurements even over as short an interval as 8 days hold incremental value in identifying DM-DTC. ΔTg/ΔTSH is a specific early biochemical marker for DM-DTC.

Multiple-factor analysis of the first radioactive iodine therapy in post-operative patients with differentiated thyroid cancer for achieving a disease-free status

¹³¹I treatment is an important management method for patients with differentiated thyroid cancer (DTC). Unsuccessful ¹³¹I ablation drastically affects the prognosis of the patients. This study aimed to analyze potential predictive factors influencing the achievement of a disease-free status following the first ¹³¹I therapy. This retrospective review included 315 DTC patients, and multiple factors were analyzed. Tumor size, pathological tumor stage, lymph node (LN) metastasis, distant metastasis, American Thyroid Association recommended risks, pre-ablation thyroglobulin (Tg), and thyroid stimulating hormone (TSH) displayed significant differences between unsuccessful and successful group. Cutoff values of Tg and TSH to predict a successful outcome were 3.525 ng/mL and 99.700 uIU/ml by receiver operating characteristic curves analysis. Binary logistic regression analysis showed that tumor stage T3 or T4, LN metastasis to N1b station, intermediate and high risks, pre-ablation Tg ≥ 3.525 ng/ml and TSH <99.700 μIU/mL were significantly associated with unsuccessful outcomes. Logistic regression equation for achieving a disease-free status could be rendered as: y (successful treatment) = −0.270–0.503 X₁ (LN metastasis) −0.236 X₂ (Tg) + 0.015 X₃ (TSH). This study demonstrated LN metastasis, pre-ablation Tg and TSH were the most powerful predictors for achieving a disease-free status by the first ¹³¹I therapy.

BEHAVIOUR OF EARLY THYROGLOBULIN AFTER TOTAL THYROIDECTOMY FOR DIFFERENTIATED THYROID CANCER

Context

The objectives of treatment of thyroid carcinoma include hormonal suppression, radioiodine ablation and follow-up with serum thyroglobulin (Tg). Tg levels should not be measured before six weeks post-thyroidectomy.

Objective

To describe the behaviour of early postoperative Tg in patients who underwent total thyroidectomy and its ability to predict the serum Tg levels after suppression.

Design

This is a retrospective cohort study.

Subjects and methods

Adult patients who underwent total thyroidectomy with at least two postoperative measurements of serum Tg, negative TgAb and concomitant serum TSH values were included. Tg, TgAb and TSH level measurements were completed two weeks postoperatively and during the follow-up period.

Results

Twenty-nine patients fulfilled all criteria. The median serum Tg level at two weeks after surgery was 3.8 ug/L (0.3 -300) with a serum TSH level of 69.9 mU/L; 11-227. At the two-week measurement, 16 (55%) patients had serum Tg levels lower than 5 ug/L and 4 patients had levels between 5-10 µg/L.

Conclusions

Postoperative early serum Tg could be an alternative to values measured six months after surgery and could be used as a predictive tool to make earlier therapeutic decisions.

Serum thyrotropin level of 30 μIU/mL is inadequate for preablative thyroglobulin to serve as a prognostic marker for differentiated thyroid cancer

PURPOSE

Preablative-stimulated thyroglobulin (ps-Tg) has manifested its potential for predicting prognosis in patients with differentiated thyroid carcinoma (DTC), but its level can be affected by thyrotropin (TSH). The objective of this study was to evaluate the utility of ps-Tg in predicting individual response after radioactive iodine (RAI) therapy, and further explore the appropriate TSH level for ps-Tg to serve as a prognostic marker in DTC without initial distant metastasis (DM).

METHODS

A total of 208 consecutive non-DM DTC patients with serial ps-Tg, TSH, and anti-Tg antibody (TgAb) measured simultaneously were enrolled. The initial and last measurements of ps-Tg were marked as Tg1 and Tg2, respectively, with a median interval of 8 days, so does TSH. Clinical response was retrospectively evaluated as excellent, indeterminate, biochemical incomplete, or structural incomplete response (ER, IDR, BIR, or SIR) after a mean follow-up of 21.5 months. Tg1 and Tg2 were tested and compared for their performances in predicting ER and incomplete response (IR, including BIR and SIR) by receiver operating characteristic (ROC) curve analysis. The 416 ps-Tg levels (Tg1 and Tg2) were then categorized by their corresponding TSH grouping of 30-<60 (n = 100), 60-<90 (n = 131), 90-<120 (n = 99), and ≥120 μIU/mL (n = 86), and the predictive performances were further compared among TSH groups.

RESULTS

Tg2, with a higher corresponding TSH level than Tg1 (median: 104.763 vs. 65.046 μIU/mL), presented higher area under the ROC curve (AUC) in predicting both ER and IR (ER: 0.889 vs. 0.836, P = 0.003; IR: 0.925 vs. 0.869, P = 0.046). The performances of ps-Tg in predicting ER and IR were both improved significantly as TSH rose from 30-<60 to 60-<90 μIU/mL, with an increase in AUC from 0.810 to 0.888 in predicting ER (P = 0.006) and from 0811 to 0.937 in predicting IR (P = 0.014), respectively. However, this kind of benefit was not further enlarged as TSH rose from 60-<90 to 90-<120 μIU/mL (both P > 0.05).

CONCLUSION

In comparison with the TSH context of 30 μIU/mL, a higher preablative TSH level of 60-<90 μIU/mL might be more appropriate for ps-Tg to serve as a prognostic marker for DTC.

Preablation Stimulated Thyroglobulin/TSH Ratio as a Predictor of Successful I(131)Remnant Ablation in Patients with Differentiated Thyroid Cancer following Total Thyroidectomy

Background. About 90% of thyroid cancers are differentiated thyroid cancers. Standard treatment is total thyroidectomy followed by radioactive I(131)remnant ablation and TSH suppression with thyroxine. Unsuccessful ablation drastically affects the prognosis of patients with DTC particularly high risk individuals; therefore, identifying the factors that affect the success of ablation is important in the management of patients with DTC. sTg is a good predictor of successful ablation in DTC. Its levels can be influenced by tumor staging and TSH values, as well as other factors. Therefore, we did this study using TSH to correct the predictive value of sTg in success of RRA. Methods. We retrospectively reviewed the records of 75 patients with DTC, who underwent total thyroidectomy followed by RRA and TSH suppression. Results. Preablation sTg and sTg/TSH ratio are significantly associated with ablation outcome. Cutoff value for sTg to predict successful and unsuccessful ablation was 18 ng/mL with 76.7% sensitivity and 79.1% specificity, while for sTg/TSH cutoff was 0.35 with 81.4% sensitivity and 81.5% specificity (P < 0.001). Association was stronger for sTg/TSH ratio with adjusted odds ratio (AOR) 11.64 (2.43-55.61) than for sTg with AOR 5.42 (1.18-24.88). Conclusions. Preablation sTg/TSH ratio can be considered as better predictor of ablation outcome than sTg, tumor size, and capsular invasion.