Serum Thyroglobulin Doubling Time in Progressive Thyroid Cancer

Impact of thyroglobulin changes on clinical outcomes of differentiated thyroid cancer with biochemical incomplete response

PURPOSE

Partial patients with biochemical incomplete response (BIR) after initial therapy for differentiated thyroid cancer (DTC) may progress to structural recurrence during follow-up. For better-individualized care, this study analyzed predictors of structural recurrence in patients with BIR after initial radioactive iodine therapy (RAIT).

METHODS

A retrospective study was conducted on 4,263 patients with DTC who underwent thyroidectomy and initial RAIT between June 2009 and August 2023. Patients with either suppressed thyroglobulin (Sup-Tg) > 1 ng/mL or stimulated Tg (Sti-Tg) > 10 ng/mL and negative anti-Tg antibodies (TgAb < 40 IU/mL) without structural disease were enrolled. Pathological examination or imaging confirmed structural recurrence. Sup-Tg change level [ΔSup-Tg% = (Sup-Tg3rd - Sup-Tg2nd)/Sup-Tg2nd × 100%] and other clinicopathological parameters were used to predict structural recurrence in patients with BIR.

RESULTS

We enrolled 161 patients with a median follow-up of 6.3 years. Fourteen patients (8.7%) progressed to structural disease, 80 (49.7%) remained in BIR status, and 67 (41.6%) recovered with long-term remission. ΔSup-Tg%≥17.08% displayed high specificity (84.4%) for structural recurrence prediction (AUC = 0.705, p = 0.011). Extrathyroid extension, stage III and ΔSup-Tg% were independent predictors of structural recurrence (OR = 4.568, p = 0.038; OR = 9.594, p = 0.015; and OR = 18.781, p < 0.001, respectively). Kaplan-Meier analysis showed that these factors were associated with structural recurrence-free survival. Cox regression analysis found that patients with stage III and ΔSup-Tg%≥17.08% have a higher risk of recurrence (HR = 4.818, p = 0.015 and HR = 10.173, p < 0.001, respectively).

CONCLUSION

Longitudinal monitoring of Tg is essential and Tg change level could be used as a predictor of structural recurrence in patients with BIR.

Diagnostic, Theranostic and Prognostic Value of Thyroglobulin in Thyroid Cancer

Thyroglobulin (Tg) is an iodinated glycoprotein, which is normally stored in the follicular colloid of the thyroid, being a substrate for thyroid hormone production. Since it is produced by well-differentiated thyroid cells, it is considered a reliable tumor marker for patients with differentiated thyroid carcinoma (DTC) during their follow-up after total thyroidectomy and radioiodine ablation. It is used to monitor residual disease and to detect recurrent disease. After total thyroid ablation, unstimulated highly sensitive Tg measurements are sufficiently accurate to avoid exogenous or endogenous thyrotropin (TSH) stimulation and provide accurate diagnostic and prognostic information in the great majority of DTC patients. Adopting sophisticated statistical analysis, i.e., decision tree models, the use of Tg before radioiodine theranostic administration was demonstrated to be useful in refining conventional, pathology-based risk stratification and providing personalized adjuvant or therapeutic radioiodine administrations. The follow-up of DTC patients aims to promptly identify patients with residual or recurrent disease following primary treatment. Our review paper covers the diagnostic, theranostic and prognostic value of thyroglobulin in DTC patients.

Metastatic differentiated thyroid cancer with negative serum stimulated Tg but positive post-therapeutic 131I-SPECT/CT scintigraphy: a single-center retrospective study

PURPOSE

This study aimed to describe the characteristics of patients with metastatic differentiated thyroid carcinoma (DTC) who had positive 131I-scintigraphy but negative stimulated thyroglobulin (sTg), and to evaluate their short-term response to radioiodine therapy (RAI).

METHODS

A total of 2250 consecutive postoperative DTC patients, who underwent RAI treatment from July 2019 to June 2022, were analyzed retrospectively. The target group was defined as stimulated Tg < 2 ng/mL with TgAb < 100 IU/mL but with post-therapeutic 131I-SPECT/CT metastases. The characteristics of these patients were analyzed and the metastatic profiles were compared with TgAb positive or sTg positive ones. A cross-sectional efficacy was evaluated 6-12 months after the RAI therapy and the treatment course until the end of the study was recorded.

RESULTS

105 (4.67%) DTC patients were post-therapeutic 131I-SPECT/CT positive and sTg negative (target group). Metastatic profiles were found significant differences between sTg negative and sTg positive ones (P < 0.001). Excellent response (ER) was achieved in 72.4% of the target group between 6-12 months of cross-sectional efficacy assessment, compared with only 12.8% in sTg positive ones (P < 0.001). The majority of the target group didn't require aggressive treatment in short-term follow-up compared with sTg positive group (P < 0.001).

CONCLUSION

The percentage of DTCs with negative sTg but positive post-therapeutic 131I-SPECT/CT was relatively low, but still significant. Moreover, the majority of these patients showed an ER to RAI and may not require the next course of therapy. Long-term follow-up is still necessary to assess recurrence and adapt surveillance in these patients.

Thyroglobulin and thyroglobulin antibody: an updated clinical and laboratory expert consensus

OBJECTIVE

Thyroglobulin measurement is the cornerstone of modern management of differentiated thyroid cancer, with clinical decisions on treatment and follow-up based on the results of such measurements. However, numerous factors need to be considered regarding measurement with and interpretation of thyroglobulin assay results.

DESIGN

The present document provides an integrated update to the 2013 and 2014 separate clinical position papers of our group on these issues.

METHODS

Issues concerning analytical and clinical aspects of highly-sensitive thyroglobulin measurement will be reviewed and discussed based on an extensive analysis of the available literature.

RESULTS

Thyroglobulin measurement remains a highly complex process with many pitfalls and major sources of interference, especially anti-thyroglobulin antibodies, need to be assessed, considered and, when necessary, dealt with appropriately.

CONCLUSIONS

Our expert consensus group formulated 53 practical, graded recommendations for guidance on highly-sensitive thyroglobulin and TgAb in laboratory and clinical practice, especially valuable where current guidelines do not offer sufficient guidance.

Survival prognostic factors for differentiated thyroid cancer patients with pulmonary metastases: A systematic review and meta-analysis

BACKGROUND

The prognostic factors for differentiated thyroid cancer (DTC) patients with pulmonary metastases (PM) remain scantly identified and analyzed. Therefore, this systematic review and meta-analysis were performed to identify and summarize the prognostic factors in adult DTC patients with PM to help distinguish patients with different prognoses and inform the rational treatment regimens.

METHOD

We performed a comprehensive search of the relevant studies published in the Cochrane Library, PubMed, Scopus, Embase, Wanfang database, VIP database, China National Knowledge Infrastructure, and Google Scholar from their inception until February 2021. The pooled hazard ratios (HR) for overall survival and/or progression-free survival (PFS) with 95% confidence intervals were applied to evaluate and identify the potential prognostic factors. Pooled OS at different time points were also calculated for the available data. A random-effects model was used in the meta-analysis.

RESULTS

The review and meta-analysis included 21 studies comprising 2722 DTC patients with PM. The prognostic factors for poor OS were: age over 40 years (HR=7.21, 95% confidence interval [CI] 1.52-34.10, P=0.01, N=788), age over 45 years (HR=2.18, 95% CI 1.26-3.77, P<0.01, N=601), male gender (HR=1.01, 95% CI 1.01-1.19, P=0.03, N=1396), follicular subtype of thyroid cancer (HR=1.63, 95% CI 1.36-1.96, P<0.01, N=2110), iodine non-avidity (HR=3.10, 95% CI 1.79-5.37, P<0.01, N=646), and metastases to other organs (HR=3.18, 95% CI 2.43-4.16, P<0.01, N=1713). Factors associated with poor PFS included age over 45 years (HR=3.85, 95% CI 1.29-11.47, P<0.01, N=306), male gender (HR=1.36, 95% CI 1.06-1.75, P=0.02, N=546), iodine non-avidity (HR=2.93, 95% CI 2.18-3.95, P<0.01, N=395), pulmonary metastatic nodule size over 10mm (HR=2.56, 95% CI 2.02-3.24, P<0.01, N=513), and extra-thyroidal invasion (HR=2.05, 95% CI 1.15-3.67, P=0.02, N=271). The pooled 1, 3, 5, 10, 15, and 20-years OS were 95.24%, 88.46%, 78.36%, 64.86%, 56.57%, and 51.03%, respectively.

CONCLUSIONS

This review and meta-analysis identified the prognostic factors of DTC patients with PM. Notably, FTC, metastases to other organs, and iodine non-avidity were particularly associated with poor prognosis. The identified prognostic factors will help guide the clinical management of DTC patients with PM.

SYSTEMATIC REVIEW REGISTRATION

https://inplasy.com/inplasy-2022-2-0026/, identifier (INPLASY202220026).

The role of thyroglobulin doubling time in differentiated thyroid cancer: a meta-analysis

OBJECTIVE

In patients with differentiated thyroid cancer (DTC), recurrences may occur in up to 20% and may have a fatal outcome in 10% of cases. Thyroglobulin doubling time (Tg-DT) values may contribute to predict response to treatment and disease recurrence in DTC patients. This study aimed to address the following questions: (1) Are Tg-DT values indicative of response to treatments in patients with DTC (i.e. 'treatment monitoring')?; (2) Is Tg-DT predictive of 2-[18F]fluoro-2-deoxy-d-glucose (2-[18F]FDG) PET/CT in patients with DTC?; (3) Are Tg-DT values predictive of DTC prognosis (i.e. 'prediction')?

DESIGN

Systematic review and meta-analysis.

METHODS

Methodology was registered in the PROSPERO database (CRD42021257947). A systematic search was carried out in PubMed, Web Of Science, and Scopus from June to August 2021 without time and language restrictions.

RESULTS

Eleven studies were included for a total of 1421 patients. Positive association between Tg-DT < 1 year and recurrence or disease progression was observed. Tg-DT was found to be related with (2-[18F]FDG) PET/CT results in patients with DTC. The area under the curve was 0.86 (95% CI: 0.83-0.89), sensitivity was 0.84 (0.64;0.94), specificity was 0.71 (0.35; 0.92), DOR was 13.1 (3.1; 55.0), LR+ was 2.9 (1.0; 8.1), LR- was 0.22 (0.1; 0.5). For patients with Tg-DT < 1 year (n = 247), the survival risk ratio was 2.09 (95% CI: 1.49; 2.94).

CONCLUSIONS

Tg-DT values are valuable in predicting response to treatment and disease recurrence in patients with DTC, as well as their overall survival. In addition, Tg-DT significantly increases the detection rate of 2-[18F]-FDG PET/CT.

The Role of Thyroglobulin in Preoperative and Postoperative Evaluation of Patients With Differentiated Thyroid Cancer

Thyroglobulin (Tg) is secreted by thyroid follicular cells and stored in the thyroid follicular lumen as a component of thyroid hormone. It is known that both benign and well-differentiated malignant thyroid tissue can secrete Tg. In recent years, growing lines of evidence have shown that Tg plays an important role in the diagnosis and metastasis of preoperative differentiated thyroid carcinoma (DTC). The levels of Tg, whether in the serum or in a fine-needle aspiration washout fluid, are usually viewed as an excellent indicator in the monitoring of postoperative DTC, including the guidance and evaluation of radioactive iodine ablation. Nevertheless, some factors limit the application of Tg, such as the method used to measure Tg and the presence of Tg antibodies. This review aimed to summarize the role of Tg in the preoperative and postoperative evaluation of patients with DTC, and the factors influencing Tg. This review could provide a reference for a more accurate application of Tg in patients with DTC.

Differentiated Thyroid Cancer with Biochemical Incomplete Response: Clinico-Pathological Characteristics and Long Term Disease Outcomes

Simple Summary

Biochemical incomplete response (BIR) is defined as elevated thyroglobulin or rising thyroglobulin antibodies following treatment without structural evidence of disease at 1–2 years after initial treatment. The long-term outcome of such patients is still poorly characterized, with some progressing to structural disease, while others maintain BIR for decades or revert to non-evidence of disease (NED). In this study, we aimed to identify factors that could predict any of the above possible outcomes. In our cohort of 83 BIR patients with a mean follow-up of 12 years, 41% progressed to structural disease. Of them, 11.8% remained BIR, and 38.2% reverted to NED.

Abstract

Although most patients with differentiated thyroid cancer (DTC) and biochemical incomplete response (BIR) follow a good clinical outcome, progression to structural disease may occur in 8–17% of patients. We aimed to identify factors that could predict the long-term outcomes of BIR patients. To this end, we conducted a retrospective review study of 1049 charts from our Differential Thyroid Cancer registry of patients who were initially treated with total thyroidectomy between 1962 and 2019. BIR was defined as suppressed thyroglobulin (Tg) > 1 ng/mL, stimulated Tg > 10 ng/mL or rising anti-Tg antibodies, who did not have structural evidence of disease, and who were assessed 12–24 months after initial treatment. We found 83 patients (7.9%) matching the definition of BIR. During a mean follow-up of 12 ± 6.6 years, 49 (59%) patients remained in a state of BIR or reverted to no evidence of disease, while 34 (41%) progressed to structural disease. At the last follow-up, three cases (3.6%) were recorded as disease-related death. The American Thyroid Association (ATA) Initial Risk Stratification system and/or AJCC/TNM (8th ed.) staging system at diagnosis predicted the shift from BIR to structural disease, irrespective of their postoperative Tg levels. We conclude that albeit 41% of BIR patients may shift to structural disease, and most have a rather indolent disease. Specific new individual data enable the Response to Therapy reclassification to become a dynamic system to allow for the better management of BIR patients in the long term.

[Treatment strategy by radioiodine refractory differentiated thyroid cancer]

Traditionally, the multimodal therapy concept for differentiated thyroid carcinomas consists of thyroidectomy with neck dissection (for cN + neck) and adjuvant radioiodine ablation with subsequent risk-adapted TSH suppression. The extent of radioiodine uptake in metastatic thyroid carcinomas plays a significant role is significant in terms of prognosis. Radioiodine refractory lesions are characterized by the lack of radioiodine uptake in combination with the lack of decrease in the tumor marker thyroglobulin as well as signs of progression on imaging. Due to the mostly indolent course over a long period of time, a wait-and-see strategy in combination with local management of distant metastase symptom relief appears to be primarily sufficient. By evidence for change in tumor dynamics, the need for a multi-tyrosine kinase inhibitor (sorafenib, lenvatinib)-based systemic therapy should be thoroughly evaluated. These substances are mostly associated with an unfavorable side-effect profile (diarrhea, rash, arterial hypertension, local wound healing disorders), which leads to a non-negligible rate of treatment-associated morbidity and a high number of treatment interruptions. For this reason, two selective RET inhibitors (selpercatinib, pralsetinib) for differentiated thyroid carcinomas were approved by the FDA in 2020. A new perspective for the future would be the variable re-differentiation strategies, which aim to increase the sensitivity of tumor cells to radioiodine.

Evaluation of a new automated assay for high-sensitivity thyroglobulin measurement and comparison with two established high-sensitivity thyroglobulin assays

Objective

Thyroglobulin (Tg) is an important tumor marker for therapy control and follow-up of differentiated thyroid carcinoma (DTC). Over the past decade, assays for highly sensitive Tg measurement have become increasingly established. We evaluated a newly developed high-sensitive Tg assay running on an automated platform (LIAISON® Tg II Gen assay, DiaSorin), with a limit of quantification of 0.10 ng/ml.

Design and Methods

Tg values of 166 sera from subjects without thyroid diseases and of more than 500 sera of well-defined DTC patients were determined with the new LIAISON® Tg II Gen assay and compared with two established assays (Elecsys® Tg II/Roche, and Medizym® Tg REM/Medipan).

Results

Tg reference values from healthy subjects were up to 37.93 ng/ml (women) resp. 24.59 ng/ml (men) with the LIAISON® Tg II Gen assay. Tg values showed good correlations in healthy subjects and patients with active tumorous disease. In contrast, Tg values in the very low range from cured thyroidectomized patients were poorly comparable between the three assays, while clinical differences between the cohorts were correctly reflected by all assays.

Conclusions

With the new LIAISON® Tg II Gen assay, another automated assay standardized against the first International Reference Preparation CRM-457 for highly sensitive measurement of Tg values is available.

Early detection of progressive disease using thyroglobulin doubling-time in metastatic differentiated thyroid carcinoma treated with radioactive iodine

OBJECTIVE

Detectable serum thyroglobulin (Tg) in patients with differentiated thyroid carcinoma (DTC) after total thyroidectomy indicates progression of the disease. Thyroglobulin doubling-time (TgDT) is a powerful prognostic predictor in patients with DTC. We aimed to evaluate the value of the dynamic TgDT for early detection of progressive disease (PD) in the patients of metastatic DTC with I radioactive iodine (RAI) therapy.

METHODS

We retrospectively evaluated 21 patients undergoing RAI therapy with metastatic DTC. Patients were defined as PD or non-PD according to Response Evaluation Criteria in Solid Tumors 1.1. TgDT was calculated by Excel-based software using Tg values measured during routine follow-up. Whole data (WDT), initial four data (IDT) and recent four data (RDT) of TgDT after total thyroidectomy were calculated and compared.

RESULTS

Among the 21 patients (10 men; median age, 62 years old; range, 33-80), 11 patients were classified into PD and 10 were into non-PD. The initial Tg after total thyroidectomy showed a significant difference between PD and non-PD patients (P = 0.013). Short WDT, IDT and RDT (less than one year) showed a high correlation with PD (P < 0.05). RDT showed the highest predictive value for PD (P < 0.001). All the 11 PD patients showed RDT less than one year before PD (median follow-up, 157 days; range, 88-252).

CONCLUSIONS

RDT is a powerful PD predictor in patients with metastatic DTC. Dynamic monitoring of RDT should be applied for the early detection of PD in clinic.

Late-onset distant metastases confer poor prognosis in patients with well-differentiated thyroid cancer

Background

Distant metastases from well-differentiated thyroid carcinoma (WDTC) occasionally occur over a wide range of time intervals after primary thyroid surgery. The prognostic impact of the timing of distant metastasis onset remains unclear.

Methods

We retrospectively reviewed the clinicopathologic features and clinical outcomes of 57 patients with WDTC and distant metastases, and evaluated the mutational profiles of BRAF, RAS, and TERT promoter genes. All patients underwent thyroidectomy and radioactive iodine (RAI) ablation using the same treatment protocol. Synchronous distant metastases were defined as those detected within 12 months of the primary WDTC diagnosis. Metachronous metastases were considered early- and late-onset diseases if detected 1-5 and ≥5 years after the primary diagnosis, respectively.

Results

In all patients, the 5- and 10-year cancer-specific survival (CSS) rates after the diagnosis of distant metastasis were 86% and 57%, respectively. Late-onset (≥5 years) metachronous distant metastasis was associated with age of ≥55 years (P=0.043) and patients refractory to RAI therapy (P=0.026). TERT promoter mutations were associated with RAI refractivity (P=0.026). BRAF V600E and RAS mutations had no prognostic significance. Bone metastasis (P=0.002) and the onset time of distant metastasis (P=0.004) were associated with poor CSS. There was no significant difference in CSS between patients with synchronous distant metastases and those with early-onset (1-5 years) metachronous distant metastases. In the multivariate analysis, bone metastasis [hazard ratio (HR) =10.24; 95% confidence interval (CI): 1.25-83.74; P=0.030] and late-onset (≥5 years) metachronous distant metastasis (HR =5.20; 95% CI: 1.01-26.63; P=0.048) were independent predictors for worse CSS.

Conclusions

The prognosis of patients with WDTC was poorer for late metachronously detected metastases than for synchronous or early metachronous metastases. Patients with distant metastasis occurring 5 years later after primary thyroid diagnosis should, therefore, be more carefully treated.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Role of Thyroglobulin Doubling Time in Differentiated Thyroid Cancer and Its Relationship with Demographic-Histopathologic Risk Factors and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Parameters

Background: Aim of this study was to investigate the relationship between thyroglobulin doubling time (TgDT) and basal risk factors and metabolic parameters derived from ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiated thyroid cancer (DTC). Materials and Methods: An analysis of 95 DTC patients who had rising serum thyroglobulin (Tg) levels under levothyroxine (LT4) suppression after radioiodine therapy was made. TgDT was calculated for 28/95 patients. The relationship between TgDT and basal demographic and histopathologic risk factors, preablative Tg, and antithyroglobulin antibody (ATg) levels and metabolic parameters was analyzed. Results: In 28 patients (15M, 13F, mean age: 52.6 ± 17.6) that TgDT could be calculated, ¹⁸F-FDG PET/CT was positive in 12 patients. Median TgDT was lower in ¹⁸F-FDG PET/CT positive patients compared to the negative cases (p < 0.05). Patients with skeletal metastasis or local recurrence had a shorter DT compared to the patients with lung metastasis. TgDT was correlated with peak standardized uptake value (SUV_peak) (p < 0.05). Maximum standardized uptake value (SUV_max) was correlated with tumor size (p < 0.05) and mean standardized uptake value (SUV_mean) with tumor size and vascular invasion (p < 0.05). Median SUV_max and SUV_mean were higher in follicular cancer or poor histological variants of papillary DTC compared to papillary cancer classical variant patients Conclusion: TgDT may be predictive of a positive ¹⁸F-FDG PET/CT in DTC. Skeletal metastasis and local recurrence are related to shorter TgDT. Greater tumor size, vascular invasion, and follicular cancer or poor variants of papillary carcinoma are related with higher SUV_max and SUV_mean. Larger scale studies are needed to confirm results and to calculate a possible cutoff of TgDT for a positive ¹⁸F-FDG PET/CT study.

Identification of Radioactive Iodine Refractory Differentiated Thyroid Cancer

Most differentiated thyroid cancer (DTC) patients have an excellent prognosis. However, about one-third of DTC patients with recurrent or metastatic disease lose the hallmark of specific iodine uptake initially or gradually and acquire radioactive iodine-refractory DTC (RAIR-DTC) with poor prognosis. Due to the potentially severe complications from unnecessarily repeated RAI therapy and encouraging progress of multiple targeted drugs for advanced RAIR-DTC patients, it has become crucial to identify RAIR-DTC early. In this review, we focus on the progress and controversies regarding the defining of RAIR-DTC, further with subsistent approaches and promising molecular nuclear medicine imaging in identifying RAIR-DTC, which may shed light on the proper management methodsof such patients.

The medical treatment of radioiodine-refractory differentiated thyroid cancers in 2019. A TUTHYREF® network review

Patients with radioiodine-refractory (RAIR) differentiated thyroid carcinoma (DTC) represent a challenging subgroup of DTC because they are at higher risk of cancer-related death. Multidisciplinary discussions can assess the role and the nature of local treatments, but also determine the optimal timing for first-line antiangiogenic therapy as some of these patients can be followed for several months or years without any treatment. In this review, we will examine the definition of RAIR-DTC, the different treatment options and finally some of the most recent cancer research breakthroughs for RAIR-DTC.

Exploratory analysis of prognostic factors for lenvatinib in radioiodine-refractory differentiated thyroid cancer

BACKGROUND

Multitarget kinase inhibitors (m-TKI), including lenvatinib, are now available as treatment options for radioiodine-refractory differentiated thyroid cancer (RR-DTC). However, the optimal timing of treatment initiation with m-TKI in these patients remains to be defined.

METHODS

We retrospectively reviewed the clinical records of 30 consecutive patients with RR-DTC. The relationship between clinical characteristics was evaluated, including tumor growth parameters at pretreatment/post-treatment and efficacy of lenvatinib.

RESULTS

A total of 26 patients with RR-DTC treated with lenvatinib were evaluable for response and eligible for analysis. From the results of multivariate analysis, baseline tumor size and tumor-related symptoms were independent negative prognostic factors for overall survival (OS) and progression-free survival (PFS). Pretreatment tumor growth parameters were not prognostic for either PFS or OS.

CONCLUSIONS

Patients with RR-DTC with a high tumor burden and tumor-related symptoms had significantly worse prognosis. Greater tumor reduction after starting lenvatinib may lead to better prognosis, irrespective of pretreatment high tumor growth rate.

The Role of Pre-ablative Stimulated Thyroglobulin and Thyroglobulin/Thyroid-Stimulating Hormone Ratio for Predicting Metastasis in Thyroid Cancer

Objectives

In this study, we aimed to investigate the predictive value of pre-ablative stimulated thyroglobulin (Tg) and Tg/thyroid-stimulating hormone (TSH) to identify lymph node metastasis (LNM) or distant metastases (DM) prior to radioactive iodine (RAI) treatment.

Methods

Patients without metastasis were included in group 1 (n=100), those with LNM were included in group 2 (n=83), and those with DM constituted group 3 (n=23). Tg and TSH values were measured approximately 4 hours prior to RAI ablation therapy.

Results

There was a significant difference between group 3 and other groups (group 1 and group 2) in terms of Tg (p<0.001) and Tg/ TSH (p<0.001). For Tg level and Tg/TSH ratio, the areas under ROC were 0.990 [95% confidence interval (CI): 0.979-1] and 0.991 (95% CI: 0.981-1), respectively. The cut-off points for Tg and Tg/TSH were 102 ng/mL and 1.06, respectively.

Conclusion

Our results suggest that Tg and Tg/TSH values can be used to predict DM. On the other hand, our study indicates that patients should be carefully evaluated for LNM even when Tg levels are l ow.

Prognostic Value of FDG-PET/CT Metabolic Parameters in Metastatic Radioiodine-Refractory Differentiated Thyroid Cancer

PURPOSE

There are no standardized prognostication algorithms for metastatic radioiodine-refractory (RAI-R) differentiated thyroid cancer (DTC). We hypothesize that [F]-FDG PET/CT may predict progression versus stability of disease based on quantitative analysis of metabolic tumor volume (MTV) and total lesion glycolysis (TLG).

METHODS

Retrospective study of 62 patients with metastatic RAI-R DTC to determine clinical outcomes with median follow-up from initial diagnosis of 11.1 years (8.38, 14.1) (range, 1.2-20 years). Baseline [F]-FDG PET/CT scans were evaluated qualitatively for regional and distant metastases and quantitatively for tumor burden based on MTV and TLG obtained using gradient segmentation method.

RESULTS

After diagnosis of metastatic RAI-R disease was established, the 5-year overall survival (OS) probability was 34%, and median OS was 3.56 years (2.87, infinity). The 5-year progression-free survival (PFS) probability was 19%, and median PFS was 1.31 years (1.03, 2.38). TSH-suppressed thyroglobulin (Tg) levels greater than 100 ng/mL and Tg doubling time (Tg-DT) less than 6 months were significantly associated with worse OS and PFS. Higher than median values of MTV and TLG were associated with worse OS (P = 0.06) and PFS (P = 0.007). Higher hazard of death was noted for higher values of log-MTV and log-TLG (HR, 1.17 [95% confidence interval, 0.99-1.39], P = 0.05, and HR, 1.14 [95% confidence interval, 1.00-1.31], P = 0.05, respectively).

CONCLUSIONS

[F]-FDG PET/CT metabolic parameters can help define the volume and biologic variations of metastatic tumor burden. Metabolic tumor volume and TLG can be used for dynamic risk stratification of patients with metastatic RAI-R DTC regarding PFS and complement Tg-DT for prognosis of clinical disease course.

THYROGLOBULIN AS A TUMOR MARKER IN DIFFERENTIATED THYROID CANCER - CLINICAL CONSIDERATIONS

SUMMARY – Initial treatment of the majority of patients with differentiated thyroid cancer (DTC) includes total thyroidectomy. Postoperative ablation therapy with radioactive iodine (I-131) is indicated in all high-risk patients, however, there is disagreement regarding its use in low- and intermediate-risk patients. Over the last few decades, thyroglobulin (Tg) has been established as the primary biochemical tumor marker for patients with DTC. Thyroglobulin can be measured during thyroid hormone therapy or after thyroid-stimulating hormone (TSH) stimulation, through thyroid hormone withdrawal or the use of human recombinant TSH. In many studies, the cut-off value for adequate Tg stimulation is a TSH value ≥30 mIU/L. However, there is an emerging body of evidence suggesting that this long-established standard should be re-evaluated, bringing this threshold into question. Recently, a risk stratification system of response to initial therapy (with four categories) has been introduced and Tg measurement is one of the main components. The relationship between the Tg/TSH ratio and the outcome of radioiodine ablation has also been studied, as well as clinical significance of serum thyroglobulin doubling-time. The postoperative serum Tg value is an important prognostic factor that is used to guide clinical management, and it is the most valuable tool in long term follow-up of patients with DTC.

Prognostic Utility of 24-Hour Urinary 5-HIAA Doubling Time in Patients With Neuroendocrine Tumors

OBJECTIVE

New clinical prognostic tools are needed to select the population of patients with neuroendocrine tumors (NETs) that have a high risk of disease progression and disease-specific mortality (DSM). Biochemical biomarker doubling time (DT) is used clinically for prognosis prediction in several solid malignancies. The aim of the current study was to determine whether 24-hour urinary 5-hydroxyindoleacetic acid (5-HIAA) level DT has any prognostic utility in patients with NETs.

METHODS

Patients with NETs were enrolled in a prospective study with comprehensive biochemical analysis. The current analysis included 90 subjects with increasing 5-HIAA levels in two consecutive measurements. DT was calculated using the Schwartz equation. The primary outcome measures were DSM and disease progression.

RESULTS

5-HIAA DT of <434 days was associated with a higher rate of DSM ( P = .02), with positive and negative predictive values for DSM of 75 and 77%, respectively. The difference in DSM was accounted for mainly by patients with small intestine or unknown primary NET ( P = .01). In addition, a shorter 5-HIAA DT in patients with small intestine or unknown primary NET was associated with a higher risk of disease progression both in univariate ( P = .001) and multivariable analyses (hazard ratio, 15.8; 95% confidence interval, 1.3 to 198.0; P = .03).

CONCLUSION

5-HIAA DT may be used as a risk stratification tool in patients with small intestine NET or NET of unknown primary after it is validated in an independent cohort and can assist in identifying patients with a high risk for disease progression and DSM.

ABBREVIATIONS

CT = computed tomography; DSM = disease-specific mortality; DT = doubling time; 5-HIAA = 5-hydroxyindoleacetic acid; MRI = magnetic resonance imaging; NET = neuroendocrine tumor; NETUP = neuroendocrine tumor of unknown primary; PET = positron emission tomography; PFS = progression-free survival; PNET = pancreatic neuroendocrine tumor; ROC = receiver operating characteristic; SINET = small-intestine neuroendocrine tumor.