Risk Stratification in Differentiated Thyroid Cancer: From Detection to Final Follow-Up

Invasion of a Recurrent Laryngeal Nerve from Small Well-Differentiated Papillary Thyroid Cancers: Patient Selection Implications for Active Surveillance

Background: The success of an active surveillance management approach to low-risk papillary thyroid cancer (PTC) is heavily dependent on proper patient selection. For example, primary tumors located in a subcapsular position immediately adjacent to the trachea or a recurrent laryngeal nerve (RLN) are considered to be inappropriate for active surveillance. Since preoperative imaging cannot reliably rule out extrathyroidal extension or reveal the full course of the RLN relative to the thyroid gland, it is important for clinicians to understand subcapsular tumor locations and minimum tumor sizes that are most likely to be associated with gross invasion of the RLNs. Methods: We assessed the medical records of 123 patients treated at Memorial Sloan Kettering Cancer Center (MSK) between 1986 and 2015 who had a primary PTC tumor demonstrating gross extrathyroidal extension to either the right or left RLN. Thirty patients with a primary tumor ≤2 cm in diameter demonstrating extrathyroidal extension into an RLN were included in the analysis. Results: Gross invasion of an RLN by tumors ≤2 cm is a rare event that was seen in only 0.8% (35/4334) of patients with PTC who underwent initial thyroid surgery at MSK between 1986 and 2015. Gross RLN invasion was associated with subcapsular PTC tumors located in either the right paratracheal area (60%), left paratracheal area (36.7%), or right lateral posterior lobe area not adjacent to the trachea (3.3%). Only a quarter of the patients had imaging findings suggestive of extrathyroidal extension and only 30% had clinically apparent vocal paresis/paralysis on preoperative examination. Invasion of the RLN was not observed for primary tumors <0.9 cm in diameter, regardless of tumor location. Conclusions: Well-differentiated PTC tumors ≥0.9 cm in maximal diameter that are located in the right paratracheal, left paratracheal, and right lateral posterior lobe subcapsular positions are usually not appropriate for active surveillance even in the absence of definitive evidence for nerve invasion on preoperative imaging or vocal cord examination. Patient selection for active surveillance management should take into account not only the size and growth rate of a tumor but also its location in relation to the expected course of RLNs.

Validation of dynamic risk stratification and impact of BRAF in risk assessment of thyroid cancer, a nation-wide multicenter study

INTRODUCTION

The dynamic risk stratification (DRS) is a relatively new system in thyroid cancer that considers the response to primary treatment to improve the initial risk of recurrence. We wanted to validate DRS system in a nationwide multicenter study and explore if the incorporation of BRAFV600E into DRS helps to better categorize and predict outcomes.

MATERIALS AND METHODS

Retrospective study of 685 patients from seven centers between 1991 and 2016, with a mean age of 48 years and a median follow-up time of 45 months (range 23-77). The overall BRAFV600E prevalence was 53.4%. We classified patients into four categories based on DRS ('excellent', 'indeterminate', 'biochemical incomplete', and 'structural incomplete' response). Cox regression was used to calculate adjusted hazard ratios (AHR) and proportions of variance explained (PVEs).

RESULTS

We found 21.6% recurrences and 2.3% cancer-related deaths. The proportion of patients that developed recurrence in excellent, indeterminate, biochemical incomplete and structural incomplete response to therapy was 1.8%, 54%, 91.7% and 96.2% respectively. Considering the outcome at the end of the follow up, patients showed no evidence of disease (NED) in 98.2, 52, 33.3 and 25.6% respectively. Patients in the structural incomplete category were the only who died (17.7%). Because they have similar outcomes in terms of NED and survival, we integrated the indeterminate and biochemical incomplete response into one unique category creating the 3-tiered DRS system. The PVEs of the AJCC/TNM staging, ATA risk classification, 4-tiered DRS, and 3-tiered DRS to predict recurrence at five years were 21%, 25%, 57% and 59% respectively. BRAFV600E was significantly associated with biochemical incomplete response (71.1 vs 28.9%) (HR 2.43; 95% CI, 1.21 to 5.23; p=0.016), but not with structural incomplete response or distant metastases. BRAF status slightly changes the AHR values of the DRS categories but is not useful for different risk grouping.

CONCLUSIONS

This is the first multicenter study to validate the 4-tiered DRS system. Our results also show that the 3-tiered DRS system, by integrating indeterminate and biochemical incomplete response into one unique category, may simplify response to therapy keeping the system accurate. BRAF status does not provide any additional benefit to DRS.

Outcomes of Patients With Metastatic Differentiated Thyroid Cancer After Excellent Response to Treatment

BACKGROUND

To evaluate the outcomes in differentiated thyroid cancer (DTC) patients who achieved excellent response to initial treatment and developed distant metastasis during follow-up.

METHODS

Thyroid cancer patients registered in Chang Gung Memorial Hospital thyroid cancer database between January 1979 and December 2019 were assessed.

RESULTS

Among 1053 DTC patients with excellent response to initial therapy, 14 (1.3%) patients developed metastatic disease during follow-up, including 6 males and 8 females with median age of 50.2 years [interquartile range (IQR), 39.9-53.7]. Nine (64.3%) patients had papillary cancer, four (28.6%) had follicular cancer, and one (7.1%) had Hürthle cell cancer. Most patients (92.9%) had stage I disease at diagnosis. The sites of metastasis were lung (71.4%), bone (7.1%), mediastinum (7.1%) and multiple sites (14.3%). With a median follow-up of 18.3 years (IQR, 14.8-23.8), 2 patients had disease-specific mortality. The 5- and 10-year disease-specific survival after the diagnosis of distant metastasis was 92% and 74%, respectively. Multiple sites of metastasis was associated with increased risk of mortality (P = 0.022).

CONCLUSIONS

A small proportion of DTC patients with an excellence response to initial therapy developed distant metastasis during follow-up. Multiple organ distant metastases conferred a worse disease-specific survival.

Papillary thyroid microcarcinoma: Is active surveillance always enough?

The incidence of papillary thyroid carcinoma (PTC) has increased over recent decades. This apparent epidemic has been attributed to the overdiagnosis of small PTC ≤10 mm in diameter (papillary thyroid microcarcinoma [PTMC]) incidentally detected on imaging for unrelated presentations. Although most PTMCs follow an indolent disease course, there is a small but significant proportion of cases that display more biologically aggressive features such as early metastasis and lymph node involvement. Management of PTMC diagnosed preoperatively should be distinguished from managing those PTMCs incidentally discovered after thyroidectomy. Here, we will focus on the challenge of managing the preoperative patient. Current guidelines recommend against routine biopsy of nodules ≤10 mm, even if they display highly suspicious features on ultrasound; however, it is not known how to identify those PTMCs at higher risk of disease progression. In view of their good prognosis even without surgical resection, active surveillance has emerged as an alternative to operative management for low-risk PTMC without lymph node involvement or distant metastasis. This review aims to summarise active surveillance data for PTMC and identify clinical features that may differentiate the indolent majority from those PTMCs that exhibit early disease progression and metastasis.

Papillary Thyroid Cancer Prognosis: An Evolving Field

Simple Summary

Over the last couple of decades, the prognostic stratification systems of differentiated thyroid cancer (DTC) patients have been revised several times in an attempt to achieve a tailored clinical management reflecting the single patients’ needs. Such revisions are likely to continue in the near future, since the prognostic value of a number of promising clinicopathological features and new molecular biomarkers are being evaluated. Here, we will review the current staging systems of thyroid cancer patients and discuss the most relevant clinicopathological parameters and new molecular markers that are potentially capable of refining the prognosis.

Abstract

Over the last few years, a great advance has been made in the comprehension of the molecular pathogenesis underlying thyroid cancer progression, particularly for the papillary thyroid cancer (PTC), which represents the most common thyroid malignancy. Putative cancer driver mutations have been identified in more than 98% of PTC, and a new PTC classification into molecular subtypes has been proposed in order to resolve clinical uncertainties still present in the clinical management of patients. Additionally, the prognostic stratification systems have been profoundly modified over the last decade, with a view to refine patients’ staging and being able to choose a clinical approach tailored on single patient’s needs. Here, we will briefly discuss the recent changes in the clinical management of thyroid nodules, and review the current staging systems of thyroid cancer patients by analyzing promising clinicopathological features (i.e., gender, thyroid auto-immunity, multifocality, PTC histological variants, and vascular invasion) as well as new molecular markers (i.e., BRAF/TERT promoter mutations, miRNAs, and components of the plasminogen activating system) potentially capable of ameliorating the prognosis of PTC patients.

Incidence and dynamic risk stratification in differentiated thyroid cancer in a high-resolution clinic, 2002-2017

OBJECTIVE

We evaluated the incidence, progression and the dynamic risk stratification in differentiated thyroid cancer (DTC) under follow-up in a high-resolution clinic (HRC).

METHODS

This was a retrospective observational study on incident cases in the tumor registry from 2002 to 2017 and their evolution under follow-up in HRC.

RESULTS

A total of 444 patients (78.5% women, 52.1±14.9 mean years old) were DTC diagnosed from 2002 to 2017. The incidence rate of DTC increased from 5.2 to 25.7×10⁵ habitants/year in women and from 2.3 to 7.1×10⁵ habitants/year in men (P<0.0001). This increased incidence was not associated with an increment in the incidental papillary microcarcinoma diagnosed (from 29.4% to 32%). In those patients undergoing follow-up at the HRC (84% papillary carcinomas), 65.7% were classified as being at a low risk of recurrence compared to 14.5% at high risk. Of those, 88.8% classified as making an excellent response at diagnosis remained disease-free at the final follow-up visit. However, those patients with an indeterminate or structurally incomplete response at diagnosis evolved to an excellent response in 55.8% and 42.9% of the cases, respectively, compared to 14.8% of those with a biochemically incomplete response (P<0.001) CONCLUSIONS: The increased incidence of DTC is similar to results published previously in other countries. Dynamic risk stratification systems adequately classify DTC patients and assess diagnostic and treatment procedures, especially in low-risk subgroups.

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.

Genomic Instability-Related LncRNA Signature Predicts the Prognosis and Highlights LINC01614 Is a Tumor Microenvironment-Related Oncogenic lncRNA of Papillary Thyroid Carcinoma

Background

Genomic instability (GI) is among the top ten characteristics of malignancy. Long non-coding RNAs (lncRNAs) are promising cancer biomarkers that are reportedly involved in GI. So far, the clinical value of GI-related lncRNAs (GIlncs) in papillary thyroid cancer (PTC) has not been clarified.

Methods

Integrative analysis of lncRNA expression and somatic mutation profiles was performed to identify GIlncs. Analysis of differentially expressed lncRNAs in the group with high- and low- cumulative number of somatic mutations revealed significant GIlncs in PTC. Univariate and multivariate Cox proportional hazard regression analyses were performed to identify hub-GIlncs.

Results

A computational model based on four lncRNAs (FOXD2-AS1, LINC01614, AC073257.2, and AC005082.1) was identified as a quantitative index using an in-silicon discovery cohort. GILS score was significantly associated with poor prognosis, as validated in the TCGA dataset and further tested in our local RNA-Seq cohort. Moreover, a combination of clinical characteristics and the composite GILS-clinical prognostic nomogram demonstrates satisfactory discrimination and calibration. Furthermore, the GILS score and FOXD2-AS1, LINC01614, AC073257.2, and AC005082.1 were also associated with driver mutations and multiple clinical-pathological variables, respectively. Moreover, RNA-Seq confirmed the expression patterns of FOXD2-AS1, LINC01614, AC073257.2, and AC005082.1 in PTC and normal thyroid tissues. Biological experiments demonstrated that downregulated or overexpressed LINC01614 affect PTC cell proliferation, migration, and invasion in vitro. Activation of the stromal and immune cell infiltration was also observed in the high LINC01614 group in the PTC microenvironment.

Conclusion

In summary, we identified a signature for clinical outcome prediction in PTC comprising four lncRNAs associated with GI. A better understanding of the GI providing an alternative evaluation of the progression risk of PTC. Our study also demonstrated LINC01614 as a novel oncogenic lncRNA and verified its phenotype in PTC.

Abandoning node dissection for desmoplasia-negative encapsulated unifocal sporadic medullary thyroid cancer

BACKGROUND

Predictive criteria to determine the absence of node metastases from thyroid specimens are scarce for sporadic medullary thyroid cancer.

METHODS

Histopathologic stratification of patients with unifocal sporadic medullary thyroid cancer ≤25 mm with ≥10 neck nodes at thyroidectomy to evaluate the suitability of desmoplasia (7 increments) and tumor capsule integrity (5 decrements) for intraoperative prediction of node metastasis in unifocal sporadic medullary thyroid cancer.

RESULTS

Paraffin-embedded thyroid specimens were available for 139 eligible patients. Significant (P < .001) associations were found between increasing desmoplasia and decreasing tumor capsule integrity and nodal disease (from 0 to 79% and 0 to 62%); the number of node metastases (medians, from 0 to 3 and 0 to 2 nodes); and biochemical cure (from 100 to 36% and 100 to 58%). Desmoplasia (low-moderate to high, with fibrosis >10%) and breach of the tumor capsule (>3 extensions; 1 extension >3 mm in width; or diffuse growth without tumor capsule) yielded excellent sensitivity and negative predictive value (100%), with moderate specificity (57 and 48%) and positive predictive value (50 and 46%). In retrospect, node dissection proved unnecessary in 55 (57%) and 47 (48%) patients who harbored desmoplasia-negative and encapsulated tumors. When available frozen sections were histopathologically compared with matching paraffin-embedded thyroid tumor specimens, concordance was 98% (53 of 54 pairs): 1 of 7 upgrades changed the diagnosis to desmoplasia, whereas 1 of 3 downgrades shifted the diagnosis of tumor capsule breach from "present" to "absent."

CONCLUSIONS

Patients with desmoplasia-negative encapsulated sporadic medullary thyroid cancer may forgo node dissection at specialist centers.

The incidence of postoperative re-stratification for recurrence in well-differentiated thyroid cancer-a retrospective cohort study

Background

After diagnosing well-differentiated thyroid cancer (WDTC), assessment of the risk for disease-specific recurrence is essential for deciding between hemi-thyroidectomy (HT) and total thyroidectomy (TT). The American Thyroid Association (ATA) 2015 guidelines suggest that patients with 1-4 cm WDTC without suspicious features may be suitable for HT. Patients' preoperatively determined risk levels are re-stratified according to surgical and final histopathological findings. The incidence and clinical implications of high-risk features discovered postoperatively in patients with preoperatively determined low-risk WDTC are yet to be better defined.

Methods

Thyroidectomies performed in the Tel-Aviv Sourasky Medical Center (TASMC) [2006-2018] were included. Patients with 1-4 cm WDTC without evidence of positive cervical lymph nodes, invasion to adjacent structures, or high-risk cytology were considered at low risk for disease-specific recurrence-suitable for lobectomy. Patients were stratified according to their risk for disease-specific recurrence, pre- and postoperatively, and the rate of completion thyroidectomy was determined.

Results

In total, 301 (21%) patients were preoperatively stratified as low risk. Forty-six of them (15%) were re-stratified postoperatively as intermediate-to-high-risk. There were no significant differences in the characteristics of the patients who maintained their original stratification to patients who were upscaled to a higher risk level postoperatively.

Conclusions

We report a 15% rate of postoperative risk escalation of patients who required completion thyroidectomy according to current ATA guidelines. In our opinion, this rate of postoperative WDTC upscaling of risk requiring more radical surgery than originally planned, is acceptable. Meticulous preoperative personalized evaluation by an experienced multidisciplinary dedicated team is essential.

Of Screening, Stratification, and Scores

Technological innovations including risk-stratification algorithms and large databases of longitudinal population health data and genetic data are allowing us to develop a deeper understanding how individual behaviors, characteristics, and genetics are related to health risk. The clinical implementation of risk-stratified screening programmes that utilise risk scores to allocate patients into tiers of health risk is foreseeable in the future. Legal and ethical challenges associated with risk-stratified cancer care must, however, be addressed. Obtaining access to the rich health data that are required to perform risk-stratification, ensuring equitable access to risk-stratified care, ensuring that algorithms that perform risk-scoring are representative of human genetic diversity, and determining the appropriate follow-up to be provided to stratification participants to alert them to changes in their risk score are among the principal ethical and legal challenges. Accounting for the great burden that regulatory requirements could impose on access to risk-scoring technologies is another critical consideration.

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.

A Joint Statement from the American Thyroid Association, the European Association of Nuclear Medicine, the European Thyroid Association, the Society of Nuclear Medicine and Molecular Imaging on Current Diagnostic and Theranostic Approaches in the Management of Thyroid Cancer

Background: The American Thyroid Association (ATA), the European Association of Nuclear Medicine, the European Thyroid Association, and the Society of Nuclear Medicine and Molecular Imaging have established an intersocietal working group to address the current controversies and evolving concepts in thyroid cancer management and therapy. The working group annually identifies topics that may significantly impact clinical practice and publishes expert opinion articles reflecting intersocietal collaboration, consensus, and suggestions for further research to address these important management issues. Summary: In 2019, the intersocietal working group identified the following topics for review and interdisciplinary discussion: (i) perioperative risk stratification, (ii) the role of diagnostic radioactive iodine (RAI) imaging in initial staging, and (iii) indicators of response to RAI therapy. Conclusions: The intersocietal working group agreed that (i) initial patient management decisions should be guided by perioperative risk stratification that should include the eighth edition American Joint Committee on Cancer staging system to predict disease specific mortality, the modified 2009 ATA risk stratification system to estimate structural disease recurrence, with judicious incorporation of molecular theranostics to further refine management recommendations; (ii) diagnostic RAI scanning in ATA intermediate risk patients should be utilized selectively rather than being considered mandatory or not necessary for all patients in this category; and (iii) a consistent semiquantitative reporting system should be used for response evaluations after RAI therapy until a reproducible and clinically practical quantitative system is validated.

Natural Course of the American Thyroid Association Response to Therapy Statuses (Dynamic Risk Stratification) in Differentiated Thyroid Cancer

The concept of response to therapy in differentiated thyroid cancer (DTC) was introduced as a dynamic risk stratification used to assess the status of the disease at the time of the evaluation during the follow-up and the risk of recurrence in the future. Our aim in this study was to evaluate the natural course over time of different response to therapy statuses.

METHODS

We studied 501 nonselected DTC patients (102 males and 399 females) with a median age of 37 years (interquartile range [IQR] 29-48). All patients underwent near-total or total thyroidectomy followed by I-131 ablation (initial management).

RESULTS

Of the 501 patients, 387 patients (77.2%) did not have any additional therapuetic interventions after the initial management. In this group, the response to therapy status at the time of the first evaluation after I-131 (median 17 months, IQR 14-22) was an excellent response in 258 (66.7%), an indeterminate response in 101 (26.1%), biochemically incomplete in 17 (4.4%), and structurally incomplete in 11 patients (2.8%). The status changed spontaneously without any intervention in many of them. At the last follow-up visit (median duration 101 months, IQR 71-126), 357 patients (92.2%) achieved an excellent response, 4 (1%) an indeterminate response, 8 (2.1%) a biochemically incomplete status, 16 (4.1%) a structurally incomplete status, and 2 (0.5%) died secondary to DTC with a structurally incomplete status. The response to therapy in the other 114 patients who underwent additional interventions changed from before intervention to the last evaluation as follows: excellent response, 0 to 60 patients (52.6%), indeterminate response, 20 (17.5%) to 1 patient (0.9%), biochemically incomplete 25 (21.9%) to 10 patients (9%), and structurally incomplete 69 (60.5%) to 43 patients (37.7%). Overall, at the last evaluation, 417 (83.2%) were in an excellent response, 5 (1%) in an indeterminate response, 18 (3.6%) in a biochemically incomplete status, 50 (10.2%) in a structurally incomplete status, and 11 (2.2%) died secondary to DTC with a structurally incomplete status.

CONCLUSIONS

The response to therapy at the initial evaluation is predictive of the long-term outcome. Most patients with the indeterminate response and some in the biochemically incomplete statuses spontaneously regress to an excellent status. Mortality and progression of DTC occur mostly in the structurally incomplete status.

Incidence and dynamic risk stratification in differentiated thyroid cancer in a high-resolution clinic, 2002-2017

OBJECTIVE

We evaluated the incidence, progression and the dynamic risk stratification in differentiated thyroid cancer (DTC) under follow-up in a high-resolution clinic (HRC).

METHODS

This was a retrospective observational study on incident cases in the tumor registry from 2002 to 2017 and their evolution under follow-up in HRC.

RESULTS

A total of 444 patients (78.5% women, 52.1±14.9 mean years old) were DTC diagnosed from 2002 to 2017. The incidence rate of DTC increased from 5.2 to 25.7x105 habitants/year in women and from 2.3 to 7.1x105 habitants/year in men (P<0.0001). This increased incidence was not associated with an increment in the incidental papillary microcarcinoma diagnosed (from 29.4% to 32%). In those patients undergoing follow-up at the HRC (84% papillary carcinomas), 65.7% were classified as being at a low risk of recurrence compared to 14.5% at high risk. Of those, 88.8% classified as making an excellent response at diagnosis remained disease-free at the final follow-up visit. However, those patients with an indeterminate or structurally incomplete response at diagnosis evolved to an excellent response in 55.8% and 42.9% of the cases, respectively, compared to 14.8% of those with a biochemically incomplete response (P<0.001) CONCLUSIONS: The increased incidence of DTC is similar to results published previously in other countries. Dynamic risk stratification systems adequately classify DTC patients and assess diagnostic and treatment procedures, especially in low-risk subgroups.

Optimal Timing of Initiating Dynamic Risk Stratification During the Early Postoperative Period in Patients with Differentiated Thyroid Carcinoma After Thyroidectomy and Radioactive Iodine Remnant Ablation

BACKGROUND

This study investigated the optimal timing to initiate assessment of the response to initial therapy during the early postoperative period in patients with differentiated thyroid carcinoma (DTC) using dynamic risk stratification (DRS).

METHODS

This historical cohort study included 510 patients with DTC who underwent a total thyroidectomy followed by radioactive iodine (RAI) remnant ablation. DRS for these patients was categorized into subgroups according to the time into the follow-up period at which the response to initial therapy was assessed. The ability of each DRS subgroup to predict the long-term structural recurrence of cancer was compared using the proportion of variance explained (PVE) from logistic regression models.

RESULTS

The median follow-up period was 108 months. Structural recurrence occurred in 7.6% of patients (n = 39/510). The PVE for long-term structural recurrence was higher among DRS subgroups (28.8-34.19%) compared with the American Joint Committee on Cancer/Union for International Cancer Control tumor-node-metastasis staging system (both the 7th and 8th editions; 4.01% and 6.13%, respectively) and the American Thyroid Association initial risk estimate (4.59%). Among the DRS subgroups, DRS assessed between 2 and 3 years after the initial surgery was associated with the highest PVE (34.19%).

CONCLUSIONS

The first assessment of DRS optimally predicts long-term structural recurrence in patients with DTC who underwent a total thyroidectomy and subsequent RAI remnant ablation at that 2- to 3-year postoperative period.

Molecular Pathology of Non-familial Follicular Epithelial-Derived Thyroid Cancer in Adults: From RAS/BRAF-like Tumor Designations to Molecular Risk Stratification

This review addresses the impact of molecular alterations on the diagnosis and prognosis of differentiated thyroid carcinoma (DTC), including papillary, follicular, and well-differentiated carcinoma NOS, as well as oncocytic neoplasms. The molecular characterization of DTC is based upon the well-established dichotomy of BRAF-like and RAS-like designations, together with a remaining third group, less homogeneous, composed of non-BRAF-/non-RAS-like tumors. The role of BRAF V600E mutation in risk stratification is discussed in the clinico-pathological context, namely, staging and invasive features of classic papillary thyroid carcinoma (PTC) and histopathological variants carrying an excellent prognosis (microPTC) or a guarded prognosis, including the aggressive variants tall cell and hobnail cell PTCs. In follicular patterned tumors, namely, follicular thyroid carcinoma (FTC), with or without oncocytic features, the most prevalent molecular alteration are RAS mutations that do not carry prognostic significance. The only genetic alteration that has been proven to play a role in risk stratification of PTC and FTC is TERT promoter (TERTp) mutation.

Current practice in patients with differentiated thyroid cancer

Considerable changes have occurred in the management of differentiated thyroid cancer (DTC) during the past four decades, based on improved knowledge of the biology of DTC and on advances in therapy, including surgery, the use of radioactive iodine (radioiodine), thyroid hormone treatment and availability of recombinant human TSH. Improved diagnostic tools are available, including determining serum levels of thyroglobulin, neck ultrasonography, imaging (CT, MRI, SPECT-CT and PET-CT), and prognostic classifications have been improved. Patients with low-risk DTC, in whom the risk of thyroid cancer death is <1% and most recurrences can be cured, currently represent the majority of patients. By contrast, patients with high-risk DTC represent 5-10% of all patients. Most thyroid cancer-related deaths occur in this group of patients and recurrences are frequent. Patients with high-risk DTC require more aggressive treatment and follow-up than patients with low-risk DTC. Finally, the strategy for treating patients with intermediate-risk DTC is frequently defined on a case-by-case basis. Prospective trials are needed in well-selected patients with DTC to demonstrate the extent to which treatment and follow-up can be limited without increasing the risk of recurrence and thyroid cancer-related death.

The effect of the area proportion of the metastatic lesion within the central metastatic lymph node on response to therapy in papillary thyroid carcinoma

Lymph node (LN) metastasis has been strongly associated with locoregional recurrence and decreased survival time of patients with papillary thyroid carcinoma (PTC). Although the characteristics of the metastatic LNs (mLN) have been determined, including size, number, micro-metastasis and extra-nodal extension (ENE), further analysis is warranted. The present study introduced a new parameter known as the area proportion of the metastatic lesion within the central mLNs (APmCLN). The objective was to evaluate the impact of the APmCLN on response to therapy in patients with PTC. In total, 355 patients with PTC treated with total thyroidectomy and neck dissection, post-operative radioactive iodine and thyroid-stimulating hormone suppression were retrospectively studied. The patients were classified into two groups: Group A (APmCLN ≤75%) and group B (APmCLN >75%). The association of various clinicopathological characteristics between these two groups was investigated. Univariate and multivariate analyses were used to evaluate risk factors associated with a non-Excellent response to therapy and recurrence-free survival (RFS). The analysis showed that APmCLN >75% was significantly associated with extra-thyroidal extension, clinically apparent nodes (cN1), pathological N1b (pN1b), ENE, greater number and larger size of central mLN and larger size of the central LN metastatic lesion. Furthermore, it was reported that chronic lymphocytic thyroiditis, larger central mLN size and APmCLN >75% were independent risk factors for a non-excellent response to therapy. Finally, it was determined that the rate of excellent response to therapy was significantly higher in pathological N1 (pN1) patients with APmCLN ≤75% (108/144, 75.0%) compared with patients with APmCLN >75% (27/47, 57.4%) (P=0.022). However, there was no significant difference (P=0.247) between patients with APmCLN ≤75% and pN0 (132/164, 80.5%). RFS was 89.4% in patients with pN1-APmCLN >75%, whereas those with pN1-APmCLN ≤75% and pN0 did not experience a relapse. Patients with PTC with APmCLN >75% should be regarded as high-risk and may require more aggressive treatment and careful follow-up.

Real-World Performance of the American Thyroid Association Risk Estimates in Predicting 1-Year Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study of 2000 Patients

Background: One of the most widely used risk stratification systems for estimating individual patients' risk of persistent or recurrent differentiated thyroid cancer (DTC) is the American Thyroid Association (ATA) guidelines. The 2015 ATA version, which has increased the number of patients considered at low or intermediate risk, has been validated in several retrospective, single-center studies. The aims of this study were to evaluate the real-world performance of the 2015 ATA risk stratification system in predicting the response to treatment 12 months after the initial treatment and to determine the extent to which this performance is affected by the treatment center in which it is used. Methods: A prospective cohort of DTC patients collected by the Italian Thyroid Cancer Observatory web-based database was analyzed. We reviewed all records present in the database and selected consecutive cases that satisfied inclusion criteria: (i) histological diagnosis of DTC, with the exclusion of noninvasive follicular thyroid neoplasm with papillary-like nuclear features; (ii) complete data of the initial treatment and pathological features; and (iii) results of 1-year follow-up visit (6-18 months after the initial treatment), including all data needed to classify the estimated response to treatment. Results: The final cohort was composed of 2071 patients from 40 centers. The ATA risk of persistent/recurrent disease was classified as low in 1109 patients (53.6%), intermediate in 796 (38.4%), and high in 166 (8.0%). Structural incomplete responses were documented in only 86 (4.2%) patients: 1.5% in the low-risk, 5.7% in the intermediate-risk, and 14.5% in the high-risk group. The baseline ATA risk class proved to be a significant predictor of structural persistent disease, both for intermediate-risk (odds ratio [OR] 4.67; 95% confidence interval [CI] 2.59-8.43) and high-risk groups (OR 16.48; CI 7.87-34.5). Individual center did not significantly influence the prediction of the 1-year disease status. Conclusions: The ATA risk stratification system is a reliable predictor of short-term outcomes in patients with DTC in real-world clinical settings characterized by center heterogeneity in terms of size, location, level of care, local management strategies, and resource availability.

Thyroglobulin Antibodies as a Prognostic Factor in Papillary Thyroid Carcinoma Patients with Indeterminate Response After Initial Therapy

The clinical outcome of papillary thyroid carcinoma (PTC) patients with an indeterminate response after initial therapy is reported to be intermediate, between incomplete and excellent responses. This study evaluated the outcomes of PTC patients with indeterminate response after initial therapy. It was further determined whether the indeterminate findings predicted outcomes more precisely. Patients were further classified into 3 groups based on risk of structural persistence/recurrence: Tg group: detectable thyroglobulin, negative antithyroglobulin antibody, regardless nonspecific imaging findings; TgAb group: positive antithyroglobulin antibody, regardless thyroglobulin levels and nonspecific imaging findings, and Image group: nonspecific findings on neck ultrasonography or faint uptake in the thyroid bed on whole-body scan, undetectable thyroglobulin and negative antithyroglobulin antibody. Sixty-six patients aged 44.1±12.7 years were studied, of whom 58 (87.9%) were females. All patients underwent total thyroidectomy, and 52 patients (78.8%) received radioiodine. After 5.7 years (P25-75 2.6-9.75 years) of follow-up, most patients (89.4%) were reclassified as having an excellent response or remained in the indeterminate response to therapy. Structural recurrence/persistence disease was detected in 7 (10.6%) patients. The persistence/recurrence rate in groups were as follow: Tg, 2.63%; TgAb, 31.25%; Image, 8.3% (p=0.007). The 10-years disease-free survival rate in the TgAb group was significantly reduced (p=0.022). Our results suggest that patients with PTC and indeterminate response due to positive serum antithyroglobulin antibody have more risk of development of structural disease. These findings suggest a more individualized follow-up strategy for patients with an indeterminate response.

Clinical management of low-risk papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PTMC) is well known to have an indolent nature with an excellent prognosis. Surgery has been the standard treatment during the past several decades, with metastasis or recurrence being exceedingly rare. Active surveillance (AS) is a new risk-adapted approach alternative to surgery that involves just watching, but not giving any treatment unless needed, not addressing the tumor itself. The patients for whom AS is adopted spend their time "with tumors." In follow-up, it is possible that alarming factors such as tumor progression appear, causing anxiety about progression. Furthermore, endless follow-up is needed. However, considering the indolent nature and unfavorable events such as surgical complications caused by surgery, AS is a good management plan for selected PTMC patients. Decision making balancing between the prognosis and unfavorable events is needed for the treatment plan. Consideration of the factors and timing of surgical conversion is also needed. In this review article, how AS should be adopted as a new management option that is an alternative to surgery, which has been the absolute choice of treatment up to recently, is discussed. Concurrently, the characteristics of the two treatment strategies are reviewed, while introducing the background that explains how AS came to attention.

Incidence and Mortality Risk Spectrum Across Aggressive Variants of Papillary Thyroid Carcinoma

Importance

While well-differentiated papillary thyroid carcinoma (WDPTC) outcomes have been well characterized, the prognostic implications of more aggressive variants are far less defined. The rarity of these subtypes has led to their consolidation as intermediate risk for what are in fact likely heterogeneous diseases.

Objective

To analyze incidence, clinicopathologic characteristics, and outcomes for aggressive variants of papillary thyroid carcinoma (PTC).

Design, Setting, and Participants

This cohort study used data from 2000 to 2016 from hospital-based and population-based US cancer registries to analyze aggressive PTC variants, including diffuse sclerosing (DSV), tall-cell (TCV), insular, and poorly differentiated (PDTC) subtypes. These variants were compared against WDPTC and anaplastic cases. Data analysis was conducted from January 2019 to October 2019.

Main Outcomes and Measures

Age-adjusted incidence was calculated via annual percentage change (APC) using the weighted least-squares method. Overall survival and disease-specific survival were analyzed via Cox regression. Propensity-score matching was used to adjust survival analyses for clinical and demographic covariates.

Results

Collectively, 5447 aggressive PTC variants were identified (including 415 DSV, 3339 TCV, 362 insular, and 1331 PDTC cases), as well as 35 812 WDPTC and 2249 anaplastic cases. Over the study period, a substantial increase in aggressive variant incidence was observed (APC, 9.1 [95% CI, 7.33-10.89]; P < .001), surpassing the relative increases observed in WDPTC (APC, 5.1 [95% CI, 3.98-6.12]; P < .001) and anaplastic cases (APC, 1.9 [95% CI, 0.75-3.05]; P = .003; parallelism P < .007). Survival varied markedly based on histologic subtype, with a wide spectrum of mortality risk noted; 10-year overall survival was 85.4% (95% CI, 84.6%-86.3%) in WDPTC, 79.2% (95% CI, 73.6%-85.3%) in DSV, 71.9% (95% CI, 68.4%-75.6%) in TCV, 45.1% (95% CI, 40.2%-50.6%) in PDTC, 27.9% (95% CI, 20.0%-38.9%) in the insular variant, and 8.9% (95% CI, 7.5%-10.6%) in anaplastic cases (P < .001). These differences largely persisted even after adjusting for inherent differences in baseline characteristics by multivariable Cox regression and propensity-score matching.

Conclusions and Relevance

An upsurge in aggressive PTC incidence was observed at a rate beyond that seen in WDPTC or anaplastic thyroid carcinoma. Moreover, long-term survival outcomes for aggressive PTC subgroups exhibit heterogeneous clinical behavior and a wide range of mortality risk, suggesting that treatment should be tailored to specific histologic subtypes. Given increasing prevalence and disparate outcomes, further investigation to identify optimal therapeutic strategies is needed in these diverse, understudied populations.

Advancements in the treatment of differentiated thyroid cancer

Derived from follicular epithelial cells, differentiated thyroid cancer (DTC) accounts for the majority of thyroid malignancies. The threefold increase in DTC incidence over the last three decades has been largely attributed to advancements in detection of papillary thyroid microcarcinomas. Efforts to address the issue of overtreatment have notably included the reclassification of encapsulated follicular variant papillary thyroid cancers (EFVPTC) to non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). In the last 5 years, the overall management approach for this relatively indolent cancer has become less aggressive. Although surgery and radioiodine ablation remain the mainstay of DTC therapy, the role of active surveillance is being explored. Furthermore, the most recent American Thyroid Association (ATA) guidelines offer flexibility between lobectomy and total thyroidectomy for thyroid nodules between 1 cm and 4 cm in the absence of extrathyroidal extension or nodal disease. As our understanding of the natural history and molecular underpinnings of DTC evolves, so might our approach to managing low-risk patients, obviating the need for invasive intervention. Simultaneously, advances in interventional and systemic therapies have greatly expanded treatment options for high-risk surgical candidates and patients with widespread disease, and continue to be areas of active investigation. Continued research efforts are essential to improve our ability to offer effective individualized therapy to patients at all disease stages and to reduce the incidence of recurrent and progressive disease.

Lung Metastasis in Children with Differentiated Thyroid Cancer: Factors Associated with Diagnosis and Outcomes of Therapy

Background: Lung metastasis from differentiated thyroid cancer (DTC) in children and young adults (CAYA) is estimated at 25%, which is 3-4 times higher than in adults. Lung metastases may respond to radioactive iodine (RAI) therapy and overall survival is excellent. Associations with lung metastasis include lateral lymph node (LN) disease although CAYA data are limited. We investigated factors associated with lung metastasis in children and adolescents and described their presentation and outcome. Methods: A retrospective review of medical records from 1998 to 2017 in patients aged <18 years treated at a tertiary pediatric center was carried out. Data on age, clinical features at diagnosis, histology, biochemistry, imaging, RAI therapy, and outcome were collected. Results: Patients treated for DTC totaled 98 and 19 of 98 (19%) patients had lung metastasis; 17 of 19 (89%) patients were identified within 6 months from thyroidectomy. Patients with lung metastasis were younger (p < 0.001)-40% <13 years old had lung metastasis-and had a larger primary tumor diameter (p = 0.01). Absence of LN disease had negative predictive values ≥90% (p < 0.02). Patients with lung metastasis had a higher postoperative thyrotropin-stimulated thyroglobulin (Tg) (p < 0.001), ≥2 ng/mL in 10 of 11 (91%) patients, and 100% had an elevated preoperative Tg (>60 ng/mL). Post-therapy whole body scan (WBS) identified most metastasis (13 of 17 patients), which were mostly diffuse (11 of 19 patients). Discordant findings were found between WBS and computed tomography (CT) at diagnosis (2 patients), WBS and CT during surveillance (3 patients), and diagnostic and post-therapy WBS (2 patients). Final outcome was "excellent" in 3 of 19 (16%) patients, "biochemically persistent" in 1 of 19 (5%) patients, "structurally persistent" in 13 of 19 (68%) patients-including 1 death-and indeterminate in 2 of 19 (11%) patients. Postoperative Tg correlated with response to therapy. Lung metastasis pattern and RAI cumulative activity were not predictive of response to therapy. Conclusions: Lung metastases are mostly observed at diagnosis of DTC and higher suspicion should be maintained in CAYA who are younger, have LN disease, and have elevated postoperative Tg. Preoperative Tg shows promise as another predictive marker, but limited sample size precludes generalization. "Excellent" response to therapy is uncommon-multiple RAI courses do not necessarily improve outcome-response appears unrelated to RAI activity or metastasis pattern.

How Does The AJCC/TNM Staging System Eighth Edition Perform in Thyroid Cancer at A Major Middle Eastern Medical Center?

OBJECTIVE

The American Joint Committee on Cancer tumor node metastasis (TNM) staging system eighth edition (TNM-8) for differentiated thyroid cancer (DTC) has been introduced as a replacement for tumor node metastasis staging system seventh edition (TNM-7). We present the first study from a Middle Eastern population comparing these 2 versions of the TNM staging system.

METHODS

We compared TNM-8 with TNM-7 in 701 patients with DTC seen during a 3-year period with a median age of 37 years (6-83) and a female-to-male ratio of 558 (79.6%) to 143 (20.4%).

RESULTS

The number (%) of patients within each stage in TNM-7 and TNM-8, respectively, are as follows: stage I = 503 (71.6%) and 583 (83.2%), stage II = 52 (7.4%) and 81 (11.4%), stage III = 53 (7.6%) and 6 (0.9%), and stage IV = 93 (13.2%) and 31 (4.6%). Overall, 172 patients (24.5%) were downstaged in TNM-8 compared to that in TNM-7, as follows: 26, 30, and 24 patients from stages II, III, and IV in TNM-7 to stage I in TNM-8; 23 and 32 patients from TNM-7 stages III and IV to TNM-8 stage II; 6 patients from stage IVa in TNM-7 to stage III in TNM-8; and 31 patients from stage IVc in TNM-7 to stage IVb in TNM-8. TNM-7 and TNM-8 predicted the long-term outcome well (median follow-up, 7.9 years), but Kaplan-Meier analysis showed better separation of cancer-specific survival in TNM-8 compared to TNM-7.

CONCLUSIONS

Compared with TNM-7, TNM-8 approximately downstaged a quarter of DTC patients and was more robust in separating the outcome of different stages over time.

Evaluation of Clinicopathological and Molecular Parameters on Disease Recurrence of Papillary Thyroid Cancer Patient: A Retrospective Observational Study

Simple Summary

Papillary thyroid cancer (PTC) patients are staged according to the Tumor-Node-Metastasis staging system (TNM). This work was aimed at comparing the usefulness of the 8th edition of TNM (TNM-8), currently used, and that of the previous one (TNM-7) for predicting disease-free interval (DFI) in a cohort of 1148 patients. Moreover, clinicopathological and molecular factors were statistically evaluated in order to determine which of these was/were the best predictor(s) of DFI. Results obtained from the multivariate analysis indicated that advanced tumor stages were independent risk factors for a lower DFI regardless of TNM, but the statistical model created with the TNM-7 was most accurate. When stage-determining factors were included individually in the multivariate analysis, LN metastases, tall cell variant, and age emerged as independent risk factors for a shorter DFI, with lateral LN metastases being the most relevant. No molecular parameters could improve the prediction of DFI provided by LN metastases.

Abstract

The American Joint Committee on Cancer has revised the Tumor-Node-Metastasis (TNM) staging system for papillary thyroid cancer (PTC) patients. We examined the impact of this new classification (TNM-8) on patient stratification and estimated the prognostic value of clinicopathological features for the disease-free interval (DFI) in a cohort of 1148 PTC patients. Kaplan–Meier analyses showed that all clinicopathological parameters analyzed, except age and multifocality, were associated significantly with DFI. Cox regression identified tall cell PTC variant and stage as independent risk factors for DFI. When the stage was replaced with age, tumor size, and lymph node (LN) metastases in the set of covariates, the lateral LN metastases stood out as the strongest independent predictor of DFI, followed by tall cell variant and age. A noteworthy result emerging from these analyzes is that regression models had lower Akaike and Bayesian information criterions if variables were categorized based on the TNM-7. In addition, we examined data from a different PTC patient cohort, acquired from The Cancer Genome Atlas database, to verify whether the DFI prediction could be enhanced by further clinicopathological and molecular parameters. However, none of these was found to be a significant predictor of DFI in the Cox model.

Course and Predictive Factors of Incomplete Response to Therapy in Low- and Intermediate-Risk Thyroid Cancer

Context

Controversy surrounds the extent and intensity of the management of American Thyroid Association (ATA) intermediate- and low-risk patients with differentiated thyroid cancer (DTC). Understanding the natural history and factors that predict outcome is important for properly tailoring the management of these patients.

Objective

This work aims to study the natural course and predictive factors of incomplete response to therapy in low- and intermediate-risk DTC.

Patients and Methods

We studied a cohort of 506 consecutive patients [418 women (82.6%) and 88 men (17.4%)] with low and intermediate risk with a median age of 35 years (interquartile range [IQR], 27-46 years). We analyzed the natural course and the predictive factors of biochemically or structurally incomplete response.

Results

Of 506 patients studied, 297 (58.7%) patients were in the low-risk group and 209 (41.3%) were in the intermediate-risk group. Over a median follow-up of 102 months (IQR, 66-130 months), 458 (90.5%) patients achieved an excellent response, 17 (3.4%) had a biochemically incomplete status, and 31 (6.1%) had a structurally incomplete status. In univariable and multivariable analyses, age (≥ 33 years) (P < .0001, odds ratio 1.06 [1.04-1.08]) and lateral lymph node metastasis (LNM; P < .0001, odds ratio 3.2 [1.7-5.9]) were strong predictive factors for biochemically and structurally incomplete response to therapy. Sex, tumor size, multifocality, extrathyroidal extension, and lymphovascular invasion did not predict incomplete response to therapy.

Conclusions

Patients with low- and intermediate-risk DTC have favorable outcomes. Age and lateral LNM are strong predictors of an incomplete response to therapy. This suggests that older patients and those with LNM should be managed and followed up more actively than younger patients and those without LNM.

Genetic Alterations in Pediatric Thyroid Cancer Using a Comprehensive Childhood Cancer Gene Panel

CONTEXT

Pediatric differentiated thyroid cancer (DTC) differs from adult DTC in its underlying genetics and clinicopathological features. In this report, we studied these aspects in 48 cases of pediatric DTC.

PATIENTS AND METHODS

We used the comprehensive Oncomine Childhood Cancer Gene panel on Ion Torrent next-generation sequencing platform. We included 48 patients (37 girls and 11 boys) with pediatric DTC (median age 17 years; range, 5-18 years) and studied the association between these genetic alterations and the clinicopathological features and outcome.

RESULTS

Of 48 tumors, 33 (69%) had somatic genetic alterations that were mutually exclusive except in one tumor. BRAFV600E and RET-PTC1 were the most common, occurring in 9 different tumors (19%) each. RET-PTC3 and ETV6-NTRK3 were the next most common, with each occurring in 4 different tumors (8%). Other genetic alterations including EML4-NTRK1, EML4-ALK, NRAS, KRAS, PTEN, and CREBBP occurred once each. There were no differences between those who had mutations and those without mutations with respect to age, sex, tumor multifocality, extrathyroidal extension, vascular invasion, lymph node or distant metastasis, and American Thyroid Association response to therapy status at the last follow-up visits. Similarly, none of these factors was different between those with fusion genes vs single-point mutations vs no mutations.

CONCLUSIONS

In pediatric DTC, fusion genes are more common than single-point mutations. The most common genetic alterations are RET-PTC1, BRAFV600E, RET-PTC3, and ETV6-NTRK3. Other alterations occur rarely. Genetic alterations do not correlate with the clinicopathological features or the outcome.

Dynamic Risk Stratification for Predicting Treatment Response in Differentiated Thyroid Cancer

Prognosis in Differentiated Thyroid Cancer (DTC) patients is excellent, but a significant degree of overtreatment still exists because of the inability to accurately identify small patient cohorts who experience a more aggressive form of the disease, often associated with certain poor prognostic factors. Identifying these cohorts at an early stage would allow patients at high risk to receive more aggressive treatment while avoiding unnecessary and invasive treatments in those at low risk. Most risk stratification systems include age, tumor size, grade, presence of local invasion, and regional or distant metastases. Here we discuss these common factors as well as their association with treatment response, but also other upcoming markers including histology and multifocality of primary tumor, dose administered and preparation method for Radioiodine Therapy (RAI), Thyroglobulin (Tg), Anti-thyroglobulin Antibodies (Tg-Ab) levels both at initial management and during follow-up, and the presence of previously existing benign thyroid disease. In addition, we examine the role of remnant size and avidity as well as surgeons' experience in performing thyroidectomies with recurrence rate, discussing its impact on disease prognosis. Our results reveal that treatment response has a statistically significant association with histology, T and M stages, surgeons' experience, Tg levels and remnant score both during RAI and follow up and Tg-Ab levels during follow-up whole body scan (WBS).

Predictors of persistent disease following initial thyroid cancer management

OBJECTIVES

To study which factors increase the risk of persistent disease in differentiated and poorly differentiated thyroid carcinoma. Methods: A retrospective chart review of all consecutive differentiated and poorly differentiated thyroid cancer patients from King Abdulaziz University Hospital, Jeddah, Kingdom of  Saudi Arabia, a tertiary care center, between 2004 and 2018. Logistic regression analysis was performed to predict factors associated with less than excellent response to treatment. Results: We included 186 patients with complete data records; 81.1% were females. Papillary thyroid carcinoma comprised 88.1% of the neoplasms. In total, 55.9% of patients attained an excellent response to treatment by the end of the first year following treatment. All patients with distant metastasis had persistent disease. On univariate analysis, female gender was associated with excellent response (p=0.002). Lymph node metastasis, extrathyroidal extension, vascular invasion, and cancer multifocality were all found to be inversely related to excellent response (p less than 0.05 for all). On multivariate analysis only lymph node metastasis was associated with a decreased adjusted odds of an excellent response (p=0.007). Conclusion: Patients with lymph node metastasis are at high risk for persistent disease following initial thyroid cancer management. Careful monitoring of these patients is warranted.

Updates on the Management of Thyroid Cancer

The diagnostic modalities, stratification tools, and treatment options for patients with thyroid cancer have rapidly evolved since the development of the American Thyroid Association (ATA) guidelines in 2015. This review compiles newer concepts in diagnosis, stratification tools and treatment options for patients with differentiated thyroid cancer (DTC), medullary thyroid carcinoma (MTC) and anaplastic thyroid cancer (ATC). Newer developments apply precision medicine in thyroid cancer patients to avoid over-treatment in low risk disease and under-treatment in high risk disease. Among novel patient-tailored therapies are selective RET inhibitors that have shown efficacy in the treatment of MTC with limited systemic toxicity compared with non-specific tyrosine kinase inhibitors. The combination of BRAF and MEK inhibitors have revolutionized management of BRAF V600E mutant ATC. Several immunotherapeutic agents are being actively investigated in the treatment of all forms of thyroid cancer. In this review, we describe the recent advances in the diagnosis and management of DTC, MTC, and ATC, with an emphasis on novel treatment modalities.

Radioactive Iodine Therapy in Differentiated Thyroid Cancer: 2020 Update

OBJECTIVE. The paradigm of theranostics is based on tailoring therapy for the purpose of optimizing outcomes. This principle is being applied to radioactive iodine therapy. Consequently, thyroid cancer therapy protocols are evolving. The purpose of this article is to promote a modern approach to radioiodine therapy. CONCLUSION. This article highlights guidelines and position statements, summarizes the prognostication systems of thyroid cancer, and reviews which prescribed activities of ¹³¹I.

Detecting Recurrence Following Lobectomy for Thyroid Cancer: Role of Thyroglobulin and Thyroglobulin Antibodies

BACKGROUND

The use of thyroglobulin (Tg) and thyroglobulin antibodies (TgAb) for detecting disease recurrence is well validated following total thyroidectomy and radioiodine ablation. However, limited data are available for patients treated with thyroid lobectomy.

METHODS

Patients who had lobectomy for papillary thyroid cancer followed for >1 year, with sufficient data on Tg and TgAb, including subgroup analysis for Hashimoto's thyroiditis and contralateral nodules.

RESULTS

One-hundred sixty-seven patients met the inclusion criteria. Average tumor size was 9.5 ± 6 mm. Following lobectomy, Tg was 12.1 ± 14.8 ng/mL. Of 52 patients with Hashimoto's thyroiditis, 38% had positive TgAb with titers of 438 ± 528 IU/mL, and in patients without TgAb the mean Tg level was 14.7 ± 19.0 ng/mL. In 34 patients with contralateral nodules ≥1 cm, Tg was 15.3 ± 17 ng/mL. During the first 2 years of follow-up, Tg declined ≥1 ng/mL in 42% of patients (by 5.1 ± 3.7 ng/mL), remained stable in 22%, and increased in 36% (by 4.9 ± 5.7 ng/mL). During a mean follow-up of 6.5 years (78 ± 43.5 months), 18 patients had completion thyroidectomy and 12 were diagnosed with contralateral cancer (n = 8) or lymph node metastases (n = 4). In patients with recurrence followed for >2 years, there was a rise in Tg in 3 cases, Tg was stable in 2 cases, and in 1 TgAb decreased from 1534 to 276 IU/mL despite metastatic lymph nodes. Basal Tg and Tg dynamics did not predict disease recurrence.

CONCLUSIONS

Serum thyroglobulin used independently is of limited value for predicting or detecting disease recurrence following thyroid lobectomy. Other potential roles of Tg, such as detecting distant metastases following lobectomy, should be further studied.

BRAF mutation and age in differentiated thyroid cancer risk stratification: Two sides of the same coin

BRAF V600E mutation is seen in about 45% of patients with Papillary Thyroid Carcinoma (PTC). Thyroid cancers are among the unique cancers where the age influences the prognosis. Current evidence suggests BRAF mutation in the presence of other risk factors in DTC is associated with poor prognosis. Considering the high prevalence of the BRAF mutation in differentiated thyroid cancer, there has been an inclination to include molecular testing as a rule-in test. However, studies have shown a reciprocal relationship between BRAF mutations and advancing age. One needs to rethink if both are two independent poor prognostic indicators. The future risk stratification systems should use technological advances to create a truly dynamic system that incorporates molecular markers in cohesion with age.

Long-term clinical outcomes of papillary thyroid carcinoma patients with biochemical incomplete response

PURPOSE

The aim of this study was to evaluate the long-term clinical outcomes of papillary thyroid carcinoma (PTC) patients exhibiting biochemical incomplete response (BIR) to initial therapy.

METHODS

We evaluated 102 patients with PTC showing a BIR during the first 12-24 months after total thyroidectomy and radioactive iodine therapy. Patients were divided into three groups according to changes in stimulated thyroglobulin (Tg) and anti-Tg antibody (TgAb) levels: the increasing TgAb group (n = 19, 18.6%), the decreasing Tg group (n = 58, 56.9%), and the increasing Tg group (n = 25, 24.5%).

RESULTS

With a median follow-up of 12 years, 43 (42%) patients had structural persistent disease as follows: 36 (84%) at regional sites and 7 (16%) at distant sites. The rate of structural persistent disease was significantly different between groups, with 21%, 41%, and 60% in the increasing TgAb, decreasing Tg, and increasing Tg groups, respectively (P = 0.012). Among patients without structural persistent disease, only 19 (18.6%) showed no evidence of disease and 40 (39.2%) were of a biochemical persistent status at the time of final follow-up. Increasing Tg after initial therapy was a significant risk factor for structural persistent disease in patients with BIR (HR, 4.16; 95% confidence interval (CI): 1.38-12.54, P = 0.011).

CONCLUSIONS

PTC patients with BIR showed a high rate of structural persistent disease and Tg change after initial therapy is the most important prognostic factor for determining clinical outcomes of these patients.

GADD45B Transcript Is a Prognostic Marker in Papillary Thyroid Carcinoma Patients Treated With Total Thyroidectomy and Radioiodine Therapy

Currently, there is a lack of efficient recurrence prediction methods for papillary thyroid carcinoma (PTC). In this study, we enrolled 202 PTC patients submitted to total thyroidectomy and radioiodine therapy with long-term follow-up (median = 10.7 years). The patients were classified as having favorable clinical outcome (PTC-FCO, no disease in the follow-up) or recurrence (PTC-RE). Alterations in BRAF, RAS, RET, and TERT were investigated (n = 202) and the transcriptome of 48 PTC (>10 years of follow-up) samples was profiled. Although no mutation was associated with the recurrence risk, 68 genes were found as differentially expressed in PTC-RE compared to PTC-FCO. Pathway analysis highlighted a potential role of cancer-related pathways, including signal transduction and FoxO signaling. Among the eight selected genes evaluated by RT-qPCR, SLC2A4 and GADD45B showed down-expression exclusively in the PTC-FCO group compared to non-neoplastic tissues (NT). Increased expression of GADD45B was an independent marker of shorter disease-free survival [hazard ratio (HR) 2.9; 95% confidence interval (CI95) 1.2-7.0] in our cohort and with overall survival in the TCGA dataset (HR = 4.38, CI95 1.2-15.5). In conclusion, GADD45B transcript was identified as a novel prognostic marker candidate in PTC patients treated with total thyroidectomy and radioiodine therapy.