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

The influence of stimulated thyroglobulin and lymphocyte subsets before radioiodine therapy on the therapeutic response in patients with intermediate- and high-risk papillary thyroid carcinoma

The aim of the present study was to investigate the factors influencing the short-term response to the initial radioiodine therapy (RT) course in patients with intermediate- and high-risk papillary thyroid carcinoma (PTC). A total of 182 patients with intermediate- and high-risk PTC who underwent RT in our hospital from March 2018 to October 2020 were retrospectively enrolled. The patients were divided into incomplete response (IR) and nonincomplete response (Non-IR) groups according to the response observed in clinical follow-up within 6-12 months after RT. Univariate and multivariate logistic regression analyses were used to investigate the effects of 15 observed factors on the response to RT. Receiver operating characteristic (ROC) curve analysis was used to determine the value of factors found to be significant in multivariate analyses for predicting an IR. A total of 182 patients with intermediate- and high-risk PTC were analyzed; the percentage of patients with a Non-IR was 61.54% (112/182), and the percentage of patients with an IR was 38.46% (70/182). The CD4+ T-cell percentage (t = 4.757, P = 0.000), CD4/CD8 (z = - 2.632, P = 0.008), stimulated thyroglobulin (sTg) level (z = - 8.273, P = 0.000) and M stage (χ2 = 17.823, P = 0.000) of the two groups were significantly different. Multivariate analysis showed that only the sTg level (OR: 1.116, 95% CI 1.068-1.165, P < 0.001) and CD4+ T-cell percentage (OR: 0.909, 95% CI 0.854-0.968, P = 0.003) were independent factors associated with the therapeutic response to RT. The cutoff sTg level and CD4+ T-cell percentage for predicting an IR were 7.62 μg/L and 40.95%, respectively. The sTg level and CD4+ T-cell percentage were verified to be independent predictive factors of RT response. Higher sTg levels and lower CD4+ T-cell percentages were related to an IR in patients with intermediate- and high-risk PTC.

Thyroglobulin/thyrotropin ratio for predicting long-term response in differentiated thyroid carcinoma: a retrospective study

OBJECTIVE

Thyrotropin-stimulated thyroglobulin (STg) after total thyroidectomy is a prognosis marker for differentiated thyroid carcinoma (DTC). As Tg level is influenced by thyrotropin (TSH), perhaps the STg/TSH ratio is also a prognosis marker for these tumours. We aimed to compare STg/TSH ratio and first STg level in differentiated thyroid carcinoma patients for their ability to predict the long-term response to initial treatment.

METHODS

This retrospective study evaluated data from 181 DTC patients for first (1st) STg and STg/TSH ratio, at 1-3 months post-total thyroidectomy and before iodine-131 therapy, according to response to initial therapy [Excellent/Indeterminate or Incomplete (Biochemical/Structural)] observed at final evaluation, and with the survival time with excellent/indeterminate response.

RESULTS

Cases with incomplete response presented higher STg level [225.13 ± 585.26 ng/mL versus (vs) 20.4 ± 192.9 ng/mL; p < 0.001] and STg/TSH ratio (3.01 ± 7.8 vs 0.27 ± 2.58; p < 0.001). Cutoffs of 5 ng/mL for STg and 0.085 for STg/TSH displayed sensitivities of 76.7% and 76.9%, and specificities of 79.2% and 82.6%, respectively, in predicting response to therapy. Values below these cutoffs were associated with longer survival time in excellent/indeterminate response (140.4 vs 15.9 and 144.6 vs 15.9 months, respectively).

CONCLUSION

STg/TSH ratio has a similar performance to the 1st STg in predicting long-term response to initial therapy.

Ablation therapy using a low dose of radioiodine may be sufficient in low- to intermediate-risk patients with follicular variant papillary thyroid carcinoma

OBJECTIVES

Follicular variant papillary thyroid carcinoma (FVPTC) is treated similarly to classical variant papillary thyroid carcinoma (cPTC). However, FVPTC has unique tumour features and behaviours. We investigated whether a low dose of radioiodine was as effective as a high dose for remnant ablation in patients with FVPTC and evaluated the recurrence of low-intermediate risk FVPTC.

METHODS

Data from cPTC and FVPTC patients treated with I-131 from 2004 to 2014 were reviewed. Demographics, tumour behaviour, lymph node metastasis, and local recurrence data were compared between FVPTC and cPTC patients. Then, low-intermediate risk FVPTC patients were divided into low, intermediate, and high I-131 dose groups, and postoperative I-131 activities were analysed to evaluate the effectiveness of I-131 therapy for thyroid remnant ablation.

RESULTS

In total, 799 cases of FVPTC (n = 168) and cPTC (n = 631) treated with I-131 were identified. Patients with FVPTC had a larger primary nodule size than cPTC, but lymph node metastases and local recurrence were more prevalent in cPTC than in FVPTC. For the low-, intermediate-, and high-dose groups, success rates of ablation did not differ (82.0%, 80%, and 81.3%, respectively).

CONCLUSION

FVPTC differs from cPTC in behaviour. Low-dose ablation may be sufficient in FVPTC patients with low-intermediate disease risk.

The Relationship of Clinicopathological Factors of the Tumor with Preoperative TSH Level in Papillary Thyroid Cancers

Objective

Thyroid-stimulating hormone/thyrotropin (TSH) is known to induce malignancies and tissue growth of the thyroid gland. While the relationship of higher levels of TSH with advanced stages of cancer had been published in previous studies, the relationship of the tumor with the clinicopathological factors had not been completely evaluated. The aim of the present study was to evaluate the relationship between highly risky clinicopathological factors with preoperative high levels of TSH.

Materials and Methods

The records of 89 patients (67 females and 22 males) who underwent surgery for differentiated thyroid cancer between 2011 and 2013 were reviewed. The relationship of preoperative TSH between tumor size, multicentricity, lymphovascular invasion, extrathyroidal extension, central neck metastasis, and lateral neck metastasis was evaluated.

Results

The preoperative TSH levels were high in patients with multicentricity (p=0.022), lymphovascular invasion (p=0.018), and central neck metastasis (p=0.002). The prevalence of extrathyroidal extension (p=0.41), lymphovascular invasion (p=0.020), and central metastasis (p=0.009) was significantly high in patients with a TSH level ≥2.5 mIU/L. The preoperative TSH levels were determined as an independent predictive risk factor for central neck metastases (p=0.012) and extrathyroidal extension (p=0.041) in multinomial logistical regression analysis.

Conclusion

The power of radiological imaging for the identification of central neck metastases in preoperative evaluation is limited. The preoperative high level of TSH is an independent predictive factor for central metastases and extrathyroidal extension. It can help to predict tumor staging. Furthermore, related with multicentricity and lymphovascular invasion, it can affect the high risk characteristics of the tumor except the stage. The preoperative TSH level can be considered for the probability of preoperative metastases and can contribute to plan the extent of surgery.

Predicting 131I-avidity of metastases from differentiated thyroid cancer using 18F-FDG PET/CT in postoperative patients with elevated thyroglobulin

The quantitative relationship between iodine and glucose metabolism in metastases from differentiated thyroid cancer (DTC) remains unknown. Aim of the prospective study was to establish the value of ¹⁸F-FDG PET/CT in predicting ¹³¹I-avidity of metastases from DTC before the first radioiodine therapy. A total of 121 postoperative DTC patients with elevated stimulated serum thyroglobulin (ssTg) who underwent ¹³¹I adjuvant therapy or therapy after ¹⁸F-FDG PET/CT scan were enrolled. The Receiver operating characteristic curve was established to create an optimal cut-off point and evaluate the value of SUVmax for predicting ¹³¹I-avidity. In our study, the median SUVmax in ¹³¹I-nonavid metastatic target lesions was also significantly higher than that in ¹³¹I-avid metastatic target lesions (5.37 vs. 3.30; P = 0.000). At a cut-off value of 4.0 in SUVmax, the area under curve was 0.62 with the sensitivity, specificity, positive predictive value and negative predictive value of 75.3%, 56.7%, 76.1%, and 54.8%, respectively. These results suggest that ¹⁸F-FDG PET/CT may be of great value in identifying metastases in postoperative DTC patients with elevated ssTg before ¹³¹I administration, leading to an improved management of disease. ¹⁸F-FDG positive metastatic DTC with SUVmax of greater than 4.0 possesses higher probability of non-avidity to radioiodine.

Quantitative thyroglobulin response to radioactive iodine treatment in predicting radioactive iodine-refractory thyroid cancer with pulmonary metastasis

OBJECTIVE

Current diagnosis of radioactive iodine (RAI)-refractory (RAIR) differentiated thyroid cancer (DTC) is based on the imaging technique, which is of a high cost. Serum thyroglobulin (Tg) is a sensitive and easily obtained biomarker. Hence, we aimed to assess the predicting value of quantitative response of Tg in earlier identifying the RAIR-DTC with pulmonary metastasis.

PATIENTS AND METHODS

Pulmonary metastatic DTC patients who underwent total or near-total thyroidectomy and at least two times of RAI therapy were included in this study. The pre-ablative stimulated Tg at the first and second RAI therapy were defined as pstim-Tg1 and pstim-Tg2, while the suppressed Tg before and after the second RAI therapy were designated sup-Tg1 and sup-Tg2. The predicted value of pstim-Tg2/Tg1 and sup-Tg2/Tg1 ratio were detected using the receiver operating characteristic (ROC) curve and logistic regression analyses.

RESULTS

Totally 115 patients were involved in this study. ROC curves showed a cut-off value of 0.544 for pstim-Tg2/ pstim-Tg1 in detecting RAIR, with a sensitivity of 0.9 and specificity of 0.477, and an area under the curve (AUC) of 0.744. Similarly, the cut-off of sup-Tg2/ sup-Tg1 was 0.972, with a sensitivity of 0.733 and specificity of 0.935, and AUC of 0.898. Univariate analysis illustrated that age, tumor size, pstim-Tg2/Tg1, sup-Tg2/ sup-Tg1 and BRAFV600E mutation were eligible to predict RAIR. While from multivariate analysis, only age, pstim-Tg2/Tg1, sup-Tg2/ sup-Tg1 and BRAFV600E mutation were verified to be the independent predictive factors.

CONCLUSION

The quantitative Tg response was encouraging in identifying RAIR-DTC with pulmonary metastasis. Age, BRAFV600E mutation and Tg response were independent predictors in predicting RAIR-DTC.

Higher preablative serum thyroid-stimulating hormone level predicts radioiodine ablation effectiveness in patients with differentiated thyroid carcinoma

INTRODUCTION

Radioiodine ablation of remnant thyroid tissue is an important adjuvant therapy of differentiated thyroid carcinoma (DTC) after thyroidectomy. Elevated serum thyroid-stimulating hormone (TSH) level is necessary for successful ablation. The optimum level of serum TSH level necessary for successful radioiodine ablation of well-DTC is, however, yet to be defined. We aimed to determine whether higher serum TSH level will result in a better rate of complete ablation of well-DTC using iodine-131 (I) following initial thyroidectomy.

PATIENTS AND METHODS

A total of 109 patients with differentiated thyroid cancer were divided into four treatment groups on the basis of serum TSH levels. They were followed up from 6 to 12 months after treatment with stimulated serum thyroglobulin level and a diagnostic whole-body scan with radioactive iodine I to determine early response.

RESULTS

Sixty-four patients had papillary thyroid carcinoma, whereas 45 patients had follicular carcinoma. An excellent response was observed in 66.7% of patients with TSH level more than 90 μIU/ml, 72.2% in the group with TSH level of 60-89 μIU/ml, 48.5% when TSH was 30-59 μIU/ml and 26.7% when TSH was less than 30 μIU/ml (P=0.002).

CONCLUSION

Higher preablative serum TSH predicts a better rate of ablation in patients with differentiated thyroid cancer treated with I after thyroidectomy.

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.