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

Prognostic role and characteristics of the indeterminate response in differentiated thyroid cancer: a systematic review

PURPOSE

The management of differentiated thyroid cancer (DTC) is actually based on a dynamic risk stratification based on classes of response to the therapy. Indeterminate response (IR) includes a heterogeneous group of patients with different characteristics, particularly different Tg and AbTg levels and/or imaging findings. The aim of systematic review (SR) is to evaluate the prognosis, diagnostic findings and other characteristics of patients in the IR class.

METHODS

A wide literature search in the Scopus, PubMed/MEDLINE and Web of Science databases was performed to find published articles on patients with DTC and IR after treatment. The quality assessment of studies was carried out using QUADAS-2 evaluation.

RESULTS

Eight articles were included in the systematic review. Six studies evaluated the prognosis and the prognostic factor in patients with IR, one study evaluated the role of 2-[18F]FDG PET-CT in the management of patients with IR and biochemical incomplete response and one study the risk factors for IR.

CONCLUSION

Patients with DTC and IR to therapy have a probability of disease relapse < 15%. Tg value could be a predictor of disease progression. The role of 2-[18F]FDG PET-CT needs to be further investigated.

Retrospective case-control study examining the relationship between recurrence-free survival and changes in pre- and post-radioiodine therapy serum thyroglobulin levels in patients with differentiated thyroid cancer

PURPOSE

Thyroglobulin assay is important to assess the residual or recurrence of differentiated thyroid cancer (DTC). Patients with positive serum thyroglobulin levels after radioactive iodine (RAI) adjuvant therapy could achieve long-term recurrence-free survival (RFS). The patient's prognosis could not be confidently estimated based solely on the evaluation of thyroglobulin levels. We investigated the recurrence rate and RFS of patients who received adjuvant RAI therapy after surgery for DTC to clarify the relationship between changes in pre- and post-therapy serum thyroglobulin levels and RFS.

MATERIALS AND METHODS

Patients who underwent adjuvant RAI therapy between May 2007 and March 2021 were included in this study, whereas those with positive anti-thyroglobulin antibodies, distant metastases, or gross residual tumors were excluded. The change in pre- and post-treatment serum thyroglobulin levels under thyroid-stimulating hormone stimulation was calculated and classified as follows: group A, thyroglobulin levels decreased by ˃10%; group B, thyroglobulin levels within a range of 10% or less; and group C, thyroglobulin levels increased by ˃10%. RFS outcomes were analyzed using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test, and multivariate analysis was performed using the Cox proportional hazard model.

RESULTS

A total of 74 patients were included. Relapse was seen in 13 of 46 patients in group A, 9 of 15 in group B, and 10 of 13 in group C. Median RFS was 129.00 (95% confidence interval CI 77.79-180.21), 113.00 (95% CI 86.83-139.17), and 33 months (95% CI 6.026-59.974) in groups A, B, and C, respectively. Patients in group C exhibited significantly shorter RFS than those in groups A and B (P = 0.001).

CONCLUSIONS

Changes in thyroglobulin levels pre- and post-therapy were associated with RFS. Patients with decreased post-therapy thyroglobulin levels had a favorable prognosis, even if their thyroglobulin levels were positive after RAI therapy.

Differentiated thyroid carcinoma: what the nonspecialists needs to know

Differentiated thyroid carcinoma (DTC) accounts for most cases of thyroid cancer, and the heterogeneity of DTC requires that management decisions be taken by a multidisciplinary team involving endocrinologists, head and neck surgeons, nuclear medicine physicians, pathologists, radiologists, radiation oncologists, and medical oncologists. It is important for nonspecialists to recognize and refer patients with DTC who will benefit from a specialized approach. Recent advances in knowledge and changes in management of DTC call for the need to raise awareness on the part of these nonspecialist physicians, including general endocrinologists and medical oncologists at large. We provide an overview of diagnostic and therapeutic principles in DTC, especially those that bear direct implication on day-to-day management of these patients by generalists. Patients with DTC may be broadly categorized as having localized, locally persistent/recurrent, or metastatic disease. Current recommendations for DTC include a three-tiered system that classifies patients with localized disease into low, intermediate, or high risk of persistent or recurrent disease. Risk stratification should be performed at baseline and repeated on an ongoing basis, depending on clinical evolution. One of the overarching goals in the management of DTC is the need to personalize treatment by tailoring its modality and intensity according to ongoing prognostic stratification, evolving knowledge about the disease, and patient characteristics and preference. In metastatic disease that is refractory to radioactive iodine, thyroid tumors are being reclassified into molecular subtypes that better reflect their biological properties and for which molecular alterations can be targeted with specific agents.

A dynamic study of the postoperative management of thyroid cancer from 2003 to 2022: a bibliometric analysis

Background

Over the past 20 years, the global incidence of thyroid cancer has continued to increase. The volume of literature on the postoperative management of thyroid cancer comprises 1,040 articles, from 64 countries, with 1,400 journals publishing the relevant literature, and several guidelines on the treatment of thyroid cancer. This study used bibliometric methods to identify research hotspots and explore future directions in this field.

Methods

We comprehensively searched the Science Citation Index Expanded (SCI-E) database of the Web of Science Core Collection (WOSCC) for articles published from 2003 to 2022 on the postoperative management of thyroid cancer. Using CiteSpace 6.1.R6 and Microsoft Office Excel 2010, we evaluated and visualized the search results. Using R Studio, we generated a network of spatial geographic distribution maps and cooperative network.

Results

A total of 1,040 publications were included in the study. The results revealed an overall upward trend in the number of publications and citations over the past 20 years. The United States of America (USA) had the largest number of publications and the highest centrality (n=282, centrality =0.28). Johns Hopkins University had highest centrality (centrality =0.15) and was the academic center of the field. Thyroid was the journal with the highest number of citations (n=826), and the American Journal of Surgical Pathology was the journal with the highest centrality (centrality =0.08). The top 10 citations in the literature were mainly guidelines and consensus statements on the management of thyroid cancer. A keyword-based clustering analysis revealed the prominence of clusters of keywords, such as follow-up, recurrent laryngeal nerve, and medullary thyroid carcinoma (MTC). A keyword burst detection analysis showed that the term papillary had the highest burst intensity (strength =8.02), while management guidelines, association guidelines, active surveillance (AS), microcarcinoma, and differentiated thyroid cancer were the current burst words.

Conclusions

Over the past two decades, the number of relevant publications in the postoperative management of thyroid cancer field has continued to grow. Among the many research directions, follow-up, recurrent laryngeal nerve, and MTC are research hotspots. Future research is likely to revolve around guidelines and consensus statements on the management of thyroid cancer, AS, and microcarcinoma in differentiated thyroid cancer.

Impact of microscopic extrathyroidal extension on differentiated thyroid cancer post-surgical risk of recurrence: a retrospective analysis

PURPOSE

In the last edition of the American Joint Committee on Cancer (AJCC) staging system, differentiated thyroid cancers (DTC) showing microscopic extrathyroidal extension (mETE) are considered comparable to intrathyroidal cancers for their clinical behavior and prognosis. The aim of the study is to evaluate the impact of this updated assessment of T, when applied to the postoperative recurrence risk stratification, according to the American Thyroid Association Guidelines (ATA-RR).

METHODS

One-hundred DTC patients who underwent total thyroidectomy were retrospectively evaluated. The downstaging of mETE was introduced in the definition of T, and the updated classification defined as modified ATA-RR (ATAm-RR). For each patient, post-surgical basal and stimulated thyroglobulin (Tg) levels, neck ultrasound (US) and post-ablative 131-I whole body scan (WBS) reports were considered. The predictive performance (PP) of disease recurrence was calculated both for each single parameter, as well as for all of them.

RESULTS

According to ATAm-RR classification, 19/100 patients (19%) were downstaged. ATA-RR proved a significant PP for disease recurrence (DR) (sensitivity 75.0%, specificity 63.0%, p = 0.023). However, ATAm-RR performed slightly better due to an increased specificity (sensitivity 75.0%, specificity 83.7%, p < 0.001). For both classifications, the PP was optimal when all the above-mentioned predictive parameters were considered.

CONCLUSION

Our results suggest that the new assessment of T considering mETE resulted in a downgrading of ATA-RR class in a significant number of patients. This provides a better PP for disease recurrence, and the best PP was obtained when considering the whole predictive variables together.

Clinical Value of Ultrasonography and Serum Markers in Preoperative N Staging of Thyroid Cancer

We aimed to determine factors influencing lymph node metastasis (LNM) and develop a more effective method to assess preoperative N staging. Overall, data of 2130 patients who underwent thyroidectomy for thyroid cancer between 2018 and 2021 were retrospectively analysed. Patients were divided into groups according to pN0, pN1a, and pN1b stages. Pathology was used to analyse the correlation between preoperative serum marker indicators and LNM. Receiver operating characteristic curves were used to compare the diagnostic value of ultrasound (US) examination alone, serum thyroglobulin, age, and combined method for LNM. A significant moderate agreement was observed between preoperative US and postoperative pathology for N staging. Between the pN0 and pN1 (pN1a + pN1b) groups, the differences in free triiodothyronine, anti-thyroid peroxidase antibody, and serum thyroglobulin levels were statistically significant. Among the indicators, serum thyroglobulin was an independent predictor of LNM. The area under the receiver operating characteristic curve was 0.610 for serum thyroglobulin level for predicting LNM, 0.689 for US alone, and 0.742 for the combined method. Both preoperative US and serum thyroglobulin level provide a specific value when evaluating the N staging of thyroid cancer, and the combined method is more valuable in the diagnosis of LNM than US alone.

Prognostic Factors for Excellent Response to Initial Therapy in Patients With Papillary Thyroid Cancer From a Prospective Multicenter Study

Prognostic factors for excellent response (ER) to initial therapy in patients with papillary thyroid cancer (PTC) have not been determined. In this study, we investigated the response to initial therapy in PTC patients and independent prognostic factors for ER in a prospective multicenter study in China. A total of 506 PTC patients from nine centers in China were enrolled in this study, all of whom underwent total or near total thyroidectomy with lymph node dissection and subsequent radioiodine therapy. Univariate and multivariable logistic regression analyses were carried out to determine the independent prognostic factors for ER. The optimal cutoff value of the number of metastatic lymph nodes for predicting ER was determined by the receiver operating characteristic curve. A total of 139 patients (27.5%) achieved ER after initial therapy. Extrathyroidal extension, the number of metastatic lymph nodes, and preablative-stimulated thyroglobulin (Ps-Tg) were independent risk factors for ER for the entire population. In a subgroup analysis, extrathyroidal extension and Ps-Tg were independent risk factors for ER in pathological N1a patients, while the number of metastatic lymph nodes and Ps-Tg were independent risk factors for ER in pathological N1b patients. The appropriate cutoff values of the number of metastatic lymph nodes in predicting ER were 5 and 13 for the entire population and pathological N1b PTC patients, respectively. PTC patients with more metastatic lymph nodes were more likely to fail to achieve ER. Extrathyroidal extension, the number of metastatic lymph nodes, and Ps-Tg were important prognostic factors for ER after initial therapy in PTC patients.

Long-Term Outcome of Differentiated Thyroid Cancer Patients-Fifty Years of Croatian Thyroid Disease Referral Centre Experience

Background: Indolent nature but a high incidence of differentiated thyroid cancer (DTC) remains a challenge for optimizing patient care. Therefore, prognostic factors present valuable information for determining an adequate clinical approach. Methods: This study assessed prognostic features of 1167 papillary (PTC) and 215 follicular (FTC) thyroid cancer patients that had undergone surgery between 1962 and 2012, and were followed-up up to 50 years in a single institution, till April 2020. Age, gender, tumor size, presence of local and distant metastases at presentation, extrathyroidal extension, disease recurrence, and cancer-specific survival were evaluated. Results: In multivariate analysis, factors affecting the worse outcome were age (p = 0.005), tumor size (p = 0.006), and distant metastases (p = 0.001) in PTC, while extrathyroidal extension (p < 0.001), neck recurrence (p = 0.002), and distant metastases (p < 0.001) in FTC patients. Loco-regional recurrence rate was 6% for PTC and 4.7% for FTC patients, while distant metastases were detected in 4.2% PTC and 14.4% of FTC patients. The 10-year cancer-specific survival rates for PTC and FTC were 98.6% and 89.8%, respectively (p < 0.001). Conclusions: Negative prognostic factors, besides distant metastases, were older age and greater tumor size in PTC, and extrathyroidal extension and neck recurrence in FTC patients. The recurrence and mortality rates were very low.

A Novel Role of Galectin-3 and Thyroglobulin in Prognosis and Differentiation of Different Stages of Thyroid Cancer and Elucidation of the Potential Contribution of Bcl-2, IL-8 and TNF-α

Thyroid cancer is among the most prevalent cancers with different types and stages. New markers are required for the prognosis and diagnosis of the disease. The present study aimed to detect the role of new markers, including galectin-3 (Gal-3) and thyroglobulin (TG), in the prognosis and staging of thyroid cancer. The study also investigated the potential apoptotic and inflammatory mechanisms involved in thyroid cancer through the determination of B-cell lymphoma 2 (Bcl-2), interleukin-8 (IL-8) and tumor necrosis factor α (TNFα) during the different stages of the cancer using a series of molecular methods. Histopathological and immunohistochemical examinations were also performed. A total of 300 subjects were classified into: 100 normal healthy subjects matched in age and sex, 100 patients with thyroid carcinoma stage I (T1N0M0) and 100 patients with thyroid carcinoma stage 2 (T2N1M1). Interestingly, the present study revealed a significant increase in the levels of TG and Gal-3 in thyroid cancer patients compared to the control group. Furthermore, the levels of Bcl-2, IL-8 and TNF-α significantly increased in the patient serum. The histopathological examination and immunohistochemical observations confirmed the molecular and hematological findings. Collectively, the present study concluded that serum TG and Gal-3 could be useful markers in the prognosis and staging of patients with thyroid cancer. Furthermore, the determination of Bax, Bcl-2, IL-8 and TNF-α levels constitute a major important marker for investigation of the mechanisms of apoptosis and inflammation in thyroid cancer. To our knowledge, this is the first study that used both galectin-3 and TG as tumor markers in the prognosis and differentiation between the different stages of cancer.

Delayed Initial Radioiodine Adjuvant Therapy Does Affect Biochemical Response in Intermediate- to High-Risk Differentiated Thyroid Cancer

Background

There are no definite recommendations on the optimal time of initiating radioactive iodine (RAI) therapy for differentiated thyroid cancer (DTC) patients in current relevant guidelines. This study aimed to investigate the relationship between the timing of initiating radioiodine adjuvant therapy (RAT) and the clinical outcomes based on dynamic follow-ups and assessments in intermediate- to high-risk DTC patients.

Methods

A total of 206 patients with intermediate- to high-risk DTC receiving RAT of 150 mCi were retrospectively reviewed. According to the time interval (TI: between thyroidectomy and initial RAT), the patients were divided into 2 groups: Group 1: TI < 3 months (n=148), and Group 2: TI ≥ 3 months (n=58). The RAT therapy response was evaluated as excellent response (ER), indeterminate response (IDR), biochemical incomplete response (BIR), structural incomplete response (SIR). The univariate and multivariate analyses were conducted to screen out factors associated with incomplete response (IR= BIR+SIR). Finally, the prognostic nomogram was used to explain IR rates as a valuable tool in clinical practice.

Results

Response to initial RAT was significantly different between 2 groups during dynamic follow-ups (all P<0.05). Group 2 had significantly lower ER rates (37.9 vs 63.5, 52.0 vs 73.9, 64.4 vs 80.3, all P<0.05, respectively) and higher IR rates (39.7 vs 14.9, 36.0 vs 9.7, 12.2 vs 3.9, all P<0.05, respectively) than group 1 during dynamic follow-ups. By univariate and multivariate analyses, prolonged TI (HR: 6.67, 95%CI: 2.241-19.857, P=0.001), soft tissue invasion (HR: 7.35, 95%CI: 1.624-33.296, P=0.010), higher sTg (HR: 7.21, 95%CI: 1.991-26.075, P=0.003) were manifested to be independent risk factors for IR. The nomogram showed that soft tissue invasion, sTg, and TI were the top 3 contributors to the IR.

Conclusions

Early RAT is associated with greater biochemical response but has no impact on SIR. Delayed initial RAT (≥3 months after thyroidectomy) related to IR in intermediate- to high-risk DTC.

Characteristics of Malignant Thyroid Tumors: A Retrospective Study on 320 Patients

Papillary thyroid cancer accounts for 80-85% of diagnosed thyroid cancers, while follicular, medullary, and anaplastic cancers are diagnosed significantly less frequently. This study aimed to show the characteristics of malignant thyroid tumors. In this retrospective study, we analyzed data from 320 patients who underwent thyroid surgery from January 2018 to December 2019. We recorded and statistically analyzed basic demographic data, data of the cytological and pathohistological findings, and tumor characteristics (size, multifocality, extrathyroidal and lymphovascular invasion). Thyroid cancer was diagnosed in 95 patients. The incidence of thyroid cancer was higher in women than in men, but without a significant difference (p=0.46). There was a significant difference between preoperative cytological findings and definitive pathohistological diagnosis (p=0.001). There was no significant difference between genders in tumor size, extrathyroidal and lymphovascular invasion, and multifocality. There were significantly more thyroid cancers with a lymphovascular invasion that were less than 2 cm in size (p=0.04). In our opinion, it is important to emphasize the value of early diagnostics and analysis of the malignant tumor characteristics that are major prognostic factors for survival in patients with thyroid cancer.

Preablative Stimulated Thyroglobulin and Thyroglobulin Reduction Index as Decision-Making Markers for Second Radioactive Iodine Therapy in Patients with Structural Incomplete Response

Purpose

The aim of this study was to evaluate the value of preablative stimulated thyroglobulin (presTg) and thyroglobulin reduction index (TRI) to predict the different responses to second radioactive iodine (RAI) therapy in differentiated thyroid cancer (DTC) patients with structural incomplete response (SIR).

Patients and Methods

A single-center retrospective study analyzed the different clinical outcomes after second RAI therapy in 206 patients with SIR. PresTg1 and presTg2 were measured before first and second RAI management and TRI was the reduction index of presTg1 and presTg2. Cut-off values of presTg and TRI were obtained using receiver operating characteristic analysis. The univariate logistic regression analysis was performed to confirm these parameters as prognostic factors to predict different responses to second RAI therapy.

Results

Only ATA risk stratification, the post-therapy whole-body scanning (Rx-WBS) findings, presTg1, presTg2, TRI, were different in patients with SIR. After second RAI therapy, 28.2% (58/206) of patients with SIR initially were reclassified as excellent response (ER). PresTg1 <6.6 ng/mL, presTg2 <1.2ng/mL, and TRI >74.2% were excellent indications to predict ER from non-ER after second RAI treatment. PresTg1 >14.9 ng/mL, presTg2 >1.8ng/mL and TRI <66.5% were well markers to predict poor outcome (SIR). High risk and distant metastases could still be considered as risk factors.

Conclusion

DTC patients with SIR could benefit through second RAI treatment. PresTg before each RAI therapy and TRI could be considered as effective decision-making markers for second RAI therapy and as predictive indications for clinical outcomes.

Molecular mechanisms of radioactive iodine refractoriness in differentiated thyroid cancer: Impaired sodium iodide symporter (NIS) expression owing to altered signaling pathway activity and intracellular localization of NIS

The advanced, metastatic differentiated thyroid cancers (DTCs) have a poor prognosis mainly owing to radioactive iodine (RAI) refractoriness caused by decreased expression of sodium iodide symporter (NIS), diminished targeting of NIS to the cell membrane, or both, thereby decreasing the efficacy of RAI therapy. Genetic aberrations (such as BRAF, RAS, and RET/PTC rearrangements) have been reported to be prominently responsible for the onset, progression, and dedifferentiation of DTCs, mainly through the activation of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT signaling pathways. Eventually, these alterations result in a lack of NIS and disabling of RAI uptake, leading to the development of resistance to RAI therapy. Over the past decade, promising approaches with various targets have been reported to restore NIS expression and RAI uptake in preclinical studies. In this review, we summarized comprehensive molecular mechanisms underlying the dedifferentiation in RAI-refractory DTCs and reviews strategies for restoring RAI avidity by tackling the mechanisms.

Thyroglobulin Measurement in Needle Aspiration for Detection of Recurrences and Neck Metastases in Patients with Differentiated Thyroid Carcinoma: Significance of Anti-Tg Antibodies

The worldwide incidence of differentiated thyroid cancer (DTC) has increased in recent decades, likely due to frequent use of cervical ultrasonography (US) and US-guided fine needle aspiration biopsy (FNA)., US is performed during follow-up after thyroidectomy, and US-guided FNA with cytology is used if suspicious cervical lymph nodes (LN) or thyroid bed masses are detected. Knowing that serum anti-Tg antibodies (sTgAb) affect the use of serum Tg (sTg) as a tumor marker, the aim of our study was to assess the usefulness of Tg determination in needle aspirates (FNA-Tg) in presence of sTgAb. This retrospective study included 149 patients with DTC and 159 aspirations of suspicious LN and thyroid bed masses. As expected, there was a negative correlation between sTg and sTgAb levels (p<0.05), while FNA-Tg levels had a positive correlation with FNA-TgAb levels (p<0.05). Furthermore, we found a positive correlation between sTg and FNA-Tg levels (p<0.05), but not between sTgAb and FNA-TgAb or sTgAb and FNA-Tg. In conclusion, these results show that FNA-Tg values were not affected by sTgAb and that FNA-Tg measurement were highly effective in detecting cervical DTC metastases. However, combined use with cytology is suggested for neck evaluation because cytology could reveal metastases from other tumor sites.

The AsSociation Between Type 2 Diabetes Mellitus, Hypothyroidism, and Thyroid Cancer

This study aimed to investigate the association between type 2 diabetes mellitus (T2DM), antidiabetic therapy, hypothyroidism, and thyroid cancer. We analyzed data from 320 patients who underwent thyroid surgery for suspicion of cancer. The diagnosis of thyroid cancer was confirmed by histopathological analysis in 95 patients. No significant difference was found in the diagnosis of T2DM and hypothyroidism concerning the presence of thyroid cancer (p=0.13; p=0.85), nor in the gender of patients with T2DM and hypothyroidism with respect to the type of thyroid cancer (p=0.19; p=0.25). Patients with T2DM (Odds ratio [OR] 1.89; 95% CI, 0.856-4.163) and patients with hypothyroidism (OR, 1.05; 95% CI, 0.530-2.164) had higher prevalence of thyroid cancer, as did those who had both diagnoses combined (p=0.37; OR, 2.39; 95% CI, 0.333-17.278), compared with the patients who did not have those diagnoses. Men with T2DM (OR, 6.19; 95% CI, 1.180-32.513) had higher prevalence of thyroid cancer than women. Patients who were on oral antidiabetics (OR, 1.91; 95% CI, 0.804-4.512) had higher prevalence of thyroid cancer than those receiving insulin. According to the results of this study, we can conclude that there is an association between T2DM, hypothyroidism, oral antidiabetics, and thyroid cancer.