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

Prognostic factors for postoperative papillary thyroid cancer with unexplained elevated Tg: A retrospective study

Objective

This study aimed to investigate the underlying reasons for unexplained elevated thyroglobulin (Tg) in postoperative papillary thyroid cancer (PTC) patients according to follow-up results post RAT and to explore the long-term clinical outcomes and prognostic factors associated with these patients.

Methods

From April 2016 to June 2019, a retrospective study was conducted on postoperative PTC patients who underwent RAT at our institution. Patients with preablative stimulated thyroglobulin (psTg) > 10 ng/mL but no structurally evident disease were enrolled. The causal categorization for elevated Tg was analyzed 6 months post RAT and the long-term therapeutic responses were assessed at the end of follow-up. To identify risk factors influencing recurrence-free survival (RFS), both univariate and multivariate Cox regression analysis were employed. Kaplan-Meier method was utilized for plotting survival curves.

Results

A cohort of 165 subjects was enrolled for the analyses. Based on the results of a six-month follow-up, the postoperative unexplained elevated Tg among 165 patients could be ultimately attributed to thyroid remnant in 13.94% (23/165), biochemical disease in 60.00% (99/165), and structural disease in 26.06% (43/165). With a median follow-up of 58 months, 51 (30.91%), 34 (20.60%), 21 (12.73%), and 59 (35.76%) of the 165 patients achieved ER, IDR, BIR and SIR, respectively. Univariate analysis showed that N stage, TNM stage and suppressed Tg 6 months post RAT may be prognostic factors affecting RFS. Multivariate analysis showed that N1b stage [HR:2.749, P = 0.003] and II/III stage [HR:2.910, P = 0.001] were independent risk factors for RFS.

Conclusion

The proportion of 165 postoperative PTC patients with unexplained elevated Tg developing structural disease within nearly 5 years was over 30%. Patients with N1b stage and higher TNM stage were more likely to develop structural disease.

Basal or stimulated thyroglobulin in evaluating response to treatment in papillary thyroid carcinoma? A retrospective cohort study

OBJECTIVE

It is not clear whether response to initial treatment in papillary thyroid carcinoma (PTC) patients is best evaluated by measuring thyroglobulin (Tg) in the presence of levothyroxine (BTg) or when stimulated by elevated TSH (STg). The aim of this study was to evaluate whether response to therapy 1 year after initial treatment changes with the use of STg in relation to BTg in PTC patients treated with total thyroidectomy (TT) and radioiodine (131I), and, if observed, to assess which response is better associated with clinical course.

SUBJECTS AND METHODS

This is a retrospective study of 148 PTC patients submitted to TT and 131I. We analyzed the response to therapy (excellent, biochemical incomplete, or indeterminate) at 1 year after initial treatment, using BTg or STg, and compared which method was better associated with "excellent response at final evaluation."

RESULTS

Twenty-eight patients (20.4%) presented change in response to therapy, with 17 of these (60.7%) presenting a worse response. Response using STg was 1.6 times better associated with proposed outcome [odds ratio (OR) = 4.61; confidence interval 95% (IC95%): 2.13-9.98] than with BTg (OR = 2.84; IC95%: 1.33-6.06).

CONCLUSION

Response to therapy at 1 year using STg was altered in approximately 20% of cases and therefore proved to be a better predictor of excellent response in the last evaluation.

Dynamic risk assessment in patients with differentiated thyroid cancer

The current approach for patients with differentiated thyroid carcinoma should be individualized according to the risk of recurrence, and this stratification could be used to identify the risk of persistent/recurrent disease in three scenarios: preoperatively, immediately postoperatively, and during long-term follow-up. The initial risk of recurrence will tailor the management of the patient in the preoperative and immediate postoperative settings, while the dynamic risk, which considers the responses to treatment, could guide the decision-making process for remnant ablation and long-term management.This review provides a summary of the existing information regarding the dynamic risk of recurrence and recommended management for patients with differentiated thyroid cancer. The application of this approach is essential to avoid unnecessary treatments for most patients who will have a favorable prognosis. On the other hand, it allows specific therapeutic interventions for those patients at high risk of recurrence. In the future, analysis of tumor biology and prospective studies will surely improve the accuracy of recurrence risk prediction.

Evaluation of progression-free survival as a surrogate endpoint for overall survival in locally advanced or metastatic differentiated thyroid cancer: a systematic review

PURPOSE

Patients with locally advanced or metastatic differentiated thyroid cancer (DTC) have a variable prognosis, and the development of more effective treatment strategies is an important research topic. Overall survival (OS) is the gold standard for research endpoints in randomized controlled trials (RCTs), but observing an OS benefit requires the inclusion of a large number of patients and a long follow-up period. In this study, we aimed to investigate whether progression-free survival (PFS) could be used as a surrogate endpoint for OS in locally advanced or metastatic DTC clinical trials.

MATERIALS AND METHODS

We conducted a search in the PubMed and EMBASE databases to include all RCTs of locally advanced or metastatic DTC and extracted survival data. A weighted linear regression analysis was performed to explore the correlation between PFS benefit and OS benefit by taking the logarithm of the hazard ratios (HRs) of PFS and OS for each trial with a base of 10 and weighted by the number of patients in each RCT.

RESULTS

Seven RCTs, including 1410 patients, were included. At the trial level, PFS benefit was weakly correlated with OS benefit (R2 = 0.210, 95% CI: 0.000-0.811) and did not meet the statistical criteria for the surrogate endpoint.

CONCLUSION

This study does not support PFS as a surrogate endpoint for OS in locally advanced or metastatic DTC clinical trials.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42022334898.

The American Thyroid Association risk stratification and long-term outcomes of differentiated thyroid cancer: a 20-year follow-up of patients in Saudi Arabia

Background

Studies have reported differing factors associated with poor outcomes in patients with differentiated thyroid cancer (DTC). We aimed to describe our 20 years of experience in the management of thyroid cancer (TC) and identify predictors of treatment outcomes.

Methods

We conducted a retrospective review of medical records of patients with TC seen in the Thyroid Center at King Saud University Medical City (KSUMC) in Riyadh, Saudi Arabia, between the years 2000 and 2020. Demographic and clinical data including pathological characteristics were collected. The American Thyroid Association (ATA) risk stratification was determined for all patients at the postoperative period as well as the response to therapy at the final follow-up visit.

Results

A total of 674 patients (mean age: 47.21 years) with TC, 571 (84.7%) of which were women, were included. There were 404 (60.0%) patients with ATA low risk, 127 (18.8%) with intermediate risk, and 143 (21.2%) with high-risk histology. Overall, 461 patients (68.4%) had an excellent response to treatment, 65 (9.6%) had an indeterminate response, 83 (12.3%) had a biochemical incomplete response, and 65 (9.6%) had a structural incomplete response. Patients who had an excellent response were mostly ATA low risk (n = 318 of 431, 68.1%), whereas 40 of 65 patients (61.5%) of those with ATA high-risk histology had a structural incomplete response to treatment. There were significantly more women who had an excellent response compared with men. Obesity, lymphovascular invasion, and size of the tumor were significant predictors of worse outcomes to therapy.

Conclusion

Tumor size, lymphovascular invasion, and obesity are strong predictors of a worse response to therapy among patients with TC. Patients with obesity should be carefully followed up regardless of their risk stratification in light of the recent compelling evidence associating obesity with thyroid cancer and its higher risk of a worse disease outcome. ATA risk stratification is well correlated with patient long-term outcomes.

Prognostic value of post-ablation stimulated thyroglobulin in differentiated thyroid cancer patients with biochemical incomplete response: a bi-center observational study

OBJECTIVE

Little is known regarding parameters predicting persistence/recurrence for differentiated thyroid cancer (DTC) patients exhibiting biochemical incomplete response (BIR) to initial therapy. High post-ablation stimulated thyroglobulin (ps-Tg) levels have undetermined prognostic significance in DTC patients with BIR. The goal of this bi-center study was to systemically assess the prognosis of DTC patients with BIR in relation to ps-Tg levels and to establish the determinants of clinical outcomes.

DESIGN AND METHODS

The retrospective study of consecutive 81 DTC patients from two tertiary centers who were classified as BIR after total thyroidectomy and radioiodine ablation between January 2010 to December 2019 were analyzed. BIR was defined as ps-Tg > 10 ng/mL measured under thyroid hormone withdrawal at 9-12 months followed by radioiodine ablation, negative anti-Tg antibodies, and no structural evidence of disease. Multivariable regression models were used to evaluate potential risk factors associated with clinical outcomes.

RESULTS

With a median follow-up of 5.4 years, 28 patients (34.6%) showed no evidence of disease and 50 patients (61.7%) were of a biochemical persistent status at the time of final follow-up. Conversely, 3 patients (3.7%) developed structural evidence of disease. Ps-Tg of 20.2 ng/mL or greater displayed the high positive predictive value (81%) for disease persistence/recurrence. Multivariate analysis revealed that only a high ps-Tg level (>20.2 ng/mL) was an independent risk factor for persistent/recurrent disease (odds ratio = 5.6; p < 0.001).

CONCLUSION

The ps-Tg (>20.2 ng/mL) was a valuable predictor of disease persistence/recurrence in DTC patients with BIR.

Predictive Factors for Skip Lymph Node Metastasis and Their Implication on Recurrence in Papillary Thyroid Carcinoma

Skip lymph node (LN) metastases in papillary thyroid carcinoma (PTC) belong to N1b classification in the absence of central neck LN involvement. This study aimed to evaluate the predictive factors of skip metastases and their impact on recurrence in PTC patients with pN1b. A total of 334 PTC patients who underwent total thyroidectomy with LN dissection (central and lateral neck compartment) followed by radioactive iodine ablation were included. Patients with skip metastases tended to have a small primary tumor (≤1 cm) and single lateral neck level involvement. Tumor size ≤ 1 cm was an important predictive factor for skip metastases. Univariate analysis for recurrence showed that patients with a central LN ratio > 0.68, lateral LN ratio > 0.21, and stimulated thyroglobulin (Tg) levels > 7.3 ng/mL had shorter RFS (recurrence-free survival). The stimulated Tg level was associated with shorter RFS on multivariate analysis (>7.3 vs. ≤7.3 ng/mL; hazard ratio, 4.226; 95% confidence interval, 2.226−8.022; p < 0.001). Although patients with skip metastases tended to have a small primary tumor and lower burden of lateral neck LN involvement, there was no association between skip metastases and RFS in PTC with pN1b. Stimulated Tg level was a strong predictor of recurrence.

Clinical-Pathological Features and Treatment Outcome of Patients With Hobnail Variant Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) with hobnail areas above 30% is classified as hobnail variant (HVPTC). Although it is widely accepted that HVPTC has a worse outcome than classical PTC, it is unclear whether PTC with hobnail features below 30% is as aggressive as HVPTC. We gathered the largest mono-institutional series of PTC with hobnail areas and HVPTC to evaluate differences in terms of pathological features of aggressiveness, molecular profile, and treatment outcome. A total of 99 PTC with hobnail features above 5% were retrospectively selected; 34 of them met the criteria for HVPTC (0.4% of all PTC diagnosed at our institution). All tumors showed high rates of extra-thyroidal extension (40.4%), lymph node metastasis (68.1% of patients with lymphadenectomy), and vascular emboli (49.5%), with no differences according to the 30% cutoff. On the other hand, distant metastases were present in HVPTC only (9.4%). Also, advanced age, advanced disease stage, and TERT promoter mutation were associated with HVPTC. More than half of the patients with follow-up had structural or biochemical persistence after 1 year from surgery. Structural persistence was significantly more common in patients with HVPTC (37.5% vs. 8.7%), while no differences were observed considering structural and biochemical persistence together. The presence of hobnail features identifies locally aggressive tumors, and, consequently, it should be always acknowledged in the pathological report. However, tumors with more than 30% hobnail areas frequently present TERT promoter mutations, advanced disease stage, and structural persistence after radioiodine ablation.

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.

Transcriptome Analysis Identified 2 New lncRNAs Associated with the Metastasis of Papillary Thyroid Carcinoma

INTRODUCTION

Papillary thyroid microcarcinoma (PTMC) is a specific subgroup of papillary thyroid carcinoma and defined with the dimension ≤1 cm by the WHO. Although it shows a relatively high 10-year livability, the metastasis of PTMC into other tissues and organs seriously affects the daily life of patients with relatively high mortality. Therefore, the genetic basis for the metastasis of PTMC needs to be explored for effective therapeutic targets. Here, we conducted a series of comparative analysis of the transcriptional expression profile between PTMC patients with and without lymph node metastasis.

METHODS

Gene expression profile and gene function were analyzed using RNA extracted from pathological tissues of 12 patients with PTMC, and the core biomarkers closely related to its metastasis were identified.

RESULTS

Our results showed that 7,507 genes and 42 RNAs showed remarkably different expression patterns. More sophisticated analysis showed that the high expression of 2 lncRNAs (T077499 and T004533) resulted in the metastasis of PTMC, which suggests that the expression pattern of the 2 lncRNAs may act as a potential biomarker for pathogenesis and prognosis of PTMC metastasis.

CONCLUSION

Our findings preliminarily reveal the molecular mechanisms for PTMC metastasis, which will provide vital reference for subsequent studies about the genetic basis and molecular targeted therapy for PTMC metastasis.

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.

Comparing lesion detection efficacy and image quality across different PET system generations to optimize the iodine-124 PET protocol for recurrent thyroid cancer

Background

In recurrent differentiated thyroid cancer patients, detectability in ¹²⁴I PET is limited for lesions with low radioiodine uptake. We assess the improvements in lesion detectability and image quality between three generations of PET scanners with different detector technologies. The results are used to suggest an optimized protocol.

Methods

Datasets of 10 patients with low increasing thyroglobulin or thyroglobulin antibody levels after total thyroidectomy and radioiodine therapies were included. PET data were acquired and reconstructed on a Biograph mCT PET/CT (whole-body, 4-min acquisition time per bed position; OSEM, OSEM-TOF, OSEM-TOF+PSF), a non-TOF Biograph mMR PET/MR (neck region, 4 min and 20 min; OSEM), and a new generation Biograph Vision PET/CT (whole-body, 4 min; OSEM, OSEM-TOF, OSEM-TOF+PSF). The 20-min image on the mMR was used as reference to calculate the detection efficacy in the neck region. Image quality was rated on a 5-point scale.

Results

All detected lesions were in the neck region. Detection efficacy was 8/9 (Vision OSEM-TOF and OSEM-TOF+PSF), 4/9 (Vision OSEM), 3/9 (mMR OSEM and mCT OSEM-TOF+PSF), and 2/9 (mCT OSEM and OSEM-TOF). Median image quality was 4 (Vision OSEM-TOF and OSEM-TOF+PSF), 3 (Vision OSEM, mCT OSEM-TOF+PSF, and mMR OSEM 20-min), 2 (mCT OSEM-TOF), 1.5 (mCT OSEM), and 1 (mMR OSEM 4 min).

Conclusion

At a clinical standard acquisition time of 4 min per bed position, the new generation Biograph Vision using a TOF-based image reconstruction demonstrated the highest detectability and image quality and should, if available, be preferably used for imaging of low-uptake lesions. A prolonged acquisition time for the mostly affected neck region can be useful.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40658-021-00361-y.

Clinical Outcomes after Early and Delayed Radioiodine Remnant Ablation in Patients with Low-Risk Papillary Thyroid Carcinoma: Propensity Score Matching Analysis

BACKGROUND

The clinical outcomes of delayed radioiodine remnant ablation (RRA) therapy in patients with low-risk papillary thyroid carcinoma (PTC) are unclear. We aimed to evaluate the clinical impact of the interval between total thyroidectomy (TT) and RRA therapy in patients with low-risk PTC.

METHODS

We included 526 patients who underwent TT and RRA for low-risk PTC with a primary tumor size of >1 cm between 2000 and 2012. Patients were divided into the early (<90 days) and the delayed (≥90 days) RRA groups based on the interval between TT and RRA. The results of diagnostic whole-body scan (DxWBS), ongoing risk stratification (ORS; response to therapy), and disease-free survival (DFS) were evaluated before and after propensity score matching (PSM).

RESULTS

Among the 526 patients, 75 (14.3%) patients underwent delayed RRA; they had more cervical lymph node metastasis and received a higher RRA dose than those who underwent early RRA. The median follow-up period was 9.1 years after initial therapy, and the structural recurrence rate was 1.9%. In DxWBS, 60 patients had focal iodine uptake limited in operative bed, with no significant difference between groups. According to ORS, 78%, 20%, 1%, and 1% patients were classified into excellent, indeterminate, biochemical incomplete, and structural incomplete response groups, respectively. There was no significant difference in ORS or DFS between groups before and after PSM.

CONCLUSION

The timing of the first RRA had no clinical impact in patients with low-risk PTC. Thus, the clinical decision for RRA can be determined >3 months after TT considering other prognostic factors.