The predictive value for excellent response to initial therapy in differentiated thyroid cancer: preablation-stimulated thyroglobulin better than the TNM stage

Prognosis and ablation success in thyroid cancer: overcoming the challenges of incomplete clinical profiles

BACKGROUND

Differentiated thyroid carcinoma (DTC) is managed by surgery followed by radioiodine (RAI) therapy in most intermediate and high-risk patients. Most nonmetastatic patients have excellent treatment responses and have long-term disease-free status. A lack of comprehensive medical services in resource-limited nation leads to attrition of critical clinical prognostication information. This study aimed to identify readily available clinical, biochemical, and histopathological parameters to predict remnant ablation success and long-term outcomes.

METHODS

The study included DTC patients who underwent RAI after surgery. Ablation success was determined by thyroglobulin (Tg) and whole-body radioiodine scan. Patients were followed for at least 5 years to assess biochemical incomplete response (BIR) and structural recurrence.

RESULTS

The study included 383 patients (a mean age of 37.8 ± 12.9 years). Successful ablation was noted in 251 (65.5%). High preablative stimulated serum Tg (presTg), papillary variants, and central and lateral compartment lymph nodal metastases were associated with ablation failure. PresTg ( P  < 0.001) was the most significant predictor. After a 102.9 ± 34.5 months follow-up, 280 (73.1%) patients were disease-free. BIR and structural recurrence were noted in 103 and 32 patients. PresTg (8.1 ± 27.7 vs. 92.3 ± 99.9 ng/ml), ATg (112.9 ± 389.8 vs. 43.2 ± 89.8 IU/ml), papillary variant, central [109 (66.1%) vs. 56 (33.9%)], and lateral compartment [65 (63.7%) vs. 37 (36.3%) lymph nodal metastases were associated ( P  < 0.05) with BIR. PresTg >10.5 ng/ml has a sensitivity and specificity of 86.6 and 86.0% for predicting BIR. Patients with successful remnant ablation and a presTg level <10.5 ng/ml had a low risk of long-term disease recurrence (less than 5%).

CONCLUSION

This ambispective study found that successful ablation and long-term disease-free survival were achievable in a significant proportion of DTC patients. BIR (26.9%) and structural recurrence (8.4%) were not uncommon. PresTg levels emerged as a crucial predictor of ablation success and subsequent outcomes. In resource-limited regions, presTg levels and ablation failure can aid in optimizing treatment strategies and improving patient care.

The Prognostic Power of Preablation Stimulated Thyroglobulin in Children With Differentiated Thyroid Cancer

OBJECTIVE

To analyze prognostic factors in children with differentiated thyroid carcinoma (DTC) who have been treated in a single center in the last 27 years.

METHODS

We studied 126 children (≤18 years old) who have been treated with near-total thyroidectomy followed by radioiodine therapy and thyroid hormone replacement. Follow-up of the patients was done 2, 6, and 12 months after treatment and then by yearly evaluation. Response to treatment was defined according to the American Thyroid Association guidelines.

RESULTS

Papillary thyroid cancer was the main pathology (93.7%), and 52.4% of the patients had lymph node metastasis at presentation, which was extensive (>5) in 30% of the patients. Distant metastasis was seen in 8.8%. The mean initial dose of I-131 was 74 ± 42.2 MBq/kg. The median follow-up was 59 months and the median time to achieve an excellent response was 29 months. The preablation stimulated thyroglobulin (psTg) level was 202.4 ± 301.8 ng/mL in patients with first-year incomplete response compared with 11.2 ± 17.5 ng/mL in others (P =.001). Furthermore, using logistic regression, the psTg level was found to be the only significant predictor of distant metastasis, and psTg ≥ 13.75 ng/mL was the most powerful predictor of first-year incomplete response. Moreover, distant metastasis was more common in boys than in girls, and it took longer time for boys to achieve an excellent response.

CONCLUSION

The psTg level was the only significant predictor of distant metastases in children with DTC, and psTg ≥ 13.75 ng/mL was the most powerful predictor of first-year incomplete response.

A Retrospective Cohort Study with Validation of Predictors of Differentiated Thyroid Cancer Outcomes

Background: The goal of radioactive iodine (RAI) in differentiated thyroid cancer (DTC) is to treat metastasis and reduce recurrence risk. International guidelines provide broad risk stratification to aid treatment decisions, but a more nuanced approach to individualize care is warranted. We developed a predictive risk model for DTC. Methods: We performed a retrospective multivariable analysis of 899 patients who received RAI after thyroidectomy at a quaternary center in Australia between 2008 and 2016. Collected data included age, gender, histology, stimulated thyroglobulin (sTg), and 8th American Joint Committee Cancer (AJCC) staging. The ATA Modified Initial Risk (ATA) was calculated retrospectively. Recurrence was defined as clinically significant progression requiring either surgical intervention or administration of a second activity of RAI. Synchronous metastasis was defined as distant metastasis (i.e., outside of the neck) that was present at the time of diagnosis on structural imaging or initial post-iodine treatment scan. The features significantly associated with synchronous metastasis or recurrence were employed in the generation of a predictive risk model. A separate cohort of 393 patients who received RAI in 2017-2021 was used for validation. Results: On multivariate analysis, sTg ≥10 μg/L, extrathyroidal extension (ETE) and lymph node involvement predicted recurrence. Independent of ATA, patients with sTg ≥10 μg/L had a shorter disease-free survival (DFS) than those with sTg <10 μg/L (p < 0.001). The ETE stratified by four histological categories was significantly associated with worse DFS (p < 0.001). In a subset of patients, the presence of thyroglobulin antibody (TgAb) did not influence recurrence in patients with sTg <10 μg/L. On multivariate analysis, widespread ETE, sTg ≥10 μg/L, multifocal papillary thyroid cancer and follicular thyroid cancer were positively associated with synchronous metastasis. A predictive risk model was developed to estimate synchronous metastasis/recurrence risk and validated successfully in the second cohort. Conclusions: Our novel predictive risk model modifies and extends ATA stratification by including sTg and ETE, which we found to be independent predictors of both recurrence and synchronous metastasis in DTC.

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.

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.

The Prognostic Role of Postablative Non-Stimulated Thyroglobulin in Differentiated Thyroid Cancer

Simple Summary

In the management of patients with differentiated thyroid cancer, thyroglobulin (Tg) is used as a tumor marker to predict residual disease. After surgery, the presence or absence of persistent disease and the risk for recurrent disease should be assessed. Risk categories may be changed during the course of disease; the reclassification of patients influences the management of the disease and the intensity of follow-up. The diagnostic and prognostic roles of postoperative stimulated and one-year postablative non-stimulated Tg was evaluated. The individual lowest and highest non-stimulated Tg values during the entire follow-up were also assessed. Non-stimulated Tg values had excellent diagnostic accuracy in predicting structural disease, and the risk classification based on these was significantly more accurate regarding outcome than that based on the postoperative stimulated Tg. Analysis of the lowest and highest Tg values highlighted that a patient’s risk category can be revised based on a single Tg measurement.

Abstract

Thyroglobulin (Tg) is the most important tumor marker in differentiated thyroid cancer (DTC). The aim of this study was to assess the diagnostic and prognostic roles of postoperative stimulated and postablative lowest, highest, and one-year non-stimulated Tg values obtained during the follow-up of patients with DTC. In this retrospective study, 222 radioiodine-treated, anti-thyroglobulin antibody (TgAb)-negative DTC patients having at least 9 months’ follow-up time were included (172 papillary and 50 follicular cancers; median age: 48 (from 15 to 91) years; female–male ratio: 158/64; median (quartiles) follow-up time: 54 (22–97) months). The 2015 American Thyroid Association guidelines were applied as criteria of the therapeutic response. Postoperative stimulated Tg values had significantly lower diagnostic accuracy than any of the non-stimulated postablative Tg values. One-year non-stimulated Tg had excellent prognostic value for structural disease: a cut-off value of 0.85 ng/mL had an 88.1% diagnostic accuracy. If the Tg value did not decrease below 0.75 ng/mL at any time during follow-up, the risk of residual disease was 25 times higher. The highest non-stimulated Tg during follow-up was the best predictor of residual disease (e.g., a Tg value exceeding 7.7 ng/mL indicated a 30-fold increase in risk). Non-stimulated Tg values measured during follow-up have excellent diagnostic accuracy to predict structural disease in DTC patients. The risk classification of a patient can safely be modified based on even a single Tg measurement.

Prognostic value of star-shaped intense uptake of 131I in thyroid cancer patients

OBJECTIVE

After ¹³¹I treatment in patients with differentiated thyroid carcinoma (DTC), we sometimes find a star-shaped intense uptake of ¹³¹I on therapeutic whole body scans (Rx-WBS), called star artifacts. Therefore, we analyzed the relevant clinical factors and prognostic value of star artifacts in DTC patients.

METHODS

809 DTC patients who received ¹³¹I treatment were retrospectively evaluated and divided into 2 groups of patients with and without star artifacts. We evaluated the therapeutic response which was divided into excellent response (ER), biochemical incomplete response (BIR), indeterminate response (IR), and structural incomplete response (SIR). Clinical factors for the presence of star artifacts were analyzed. We also compared the rate of ER, BIR, IR, SIR and recurrence rate between group 1 and group 2.

RESULTS

The major clinical factors included stimulated thyroglobulin (sTg)>1.8ng/ml, 24h radioiodine uptake (RAIU)>2.2%, and positive ^99mTcO4^- thyroid imaging for the presence of star artifacts. In patients with sTg levels>10ng/ml, patients in group 1 had a higher rate of ablation success and ER than patients in group 2 (80.2% vs 65.6%, P=0.038, 31.6% vs 13.1%, P=0.008, respectively) and had a similar rate of BIR, IR, SIR. Recurrence rate was similar between group 1 and group 2 (5.2% vs 3.1%, P=0.13).

CONCLUSION

More remnant thyroid tissue is one of the factors associated with the presence of star artifacts on Rx-WBS. Patients with star artifacts exhibit a better therapeutic response (ER) when sTg levels are >10ng/ml. However, star artifacts have no effect on the recurrence rate.

Optimization of serum thyroglobulin measured at different time points for prognostic evaluation in differentiated thyroid carcinoma patients

Although serum thyroglobulin (Tg) is a reliable differentiated thyroid carcinoma (DTC) prognostic marker, its cutoff values can be affected by TSH stimulation status. Serum Tg prognostic values measured at different time points before and after radioactive iodine (RAI) therapy prepared with recombinant human TSH (rhTSH) in DTC patients, were investigated.This study included 160 DTC patients who underwent surgery followed by rhTSH-aided RAI therapy. Their serum Tg levels were measured 7 days before (D-7Tg), on the day of (D0Tg), and 2 days after (D2Tg) the RAI therapy. For response evaluation, the patients were classified into 2 groups: acceptable response and non-acceptable response (non-AR). Optimal Tg level cutoff values measured at different time points were evaluated for persistent or recurrent disease (PRD) prediction, as well as therapeutic response.Multivariate analysis showed that D-7Tg, D0Tg, and D2Tg significantly predicted non-AR (P < .05, for all). Optimal Tg level cutoff values for non-AR prediction were 0.6, 2.6, and 3.7 ng/mL for D-7Tg, D0Tg, and D2Tg, respectively. Cox regression analysis showed that Tg levels were significantly associated with PRD free survival with D-7Tg, D0Tg, and D2Tg cutoff values of 0.8, 4.0, and 6.0 ng/mL, respectively (D-7Tg, P = .010; D0Tg, P = .005; D2Tg, P = .011).Serum Tg levels measured at the different time points could predict PRD free survival as well as therapeutic response with different cutoff values in DTC patients who underwent rhTSH-aided RAI therapy.

Prognostic value and optimal threshold of first thyroglobulin in low/intermediate risk DTC

BACKGROUND

The aim of this study was to define prognostic value and optimal threshold of first thyroglobulin (fTg) measured after thyroidectomy and just before radio-iodine therapy (RIT), in low/intermediate risk patients with differentiated thyroid cancer (DTC).

METHODS

This is a retrospective study in 383 patients with DTC who were treated with surgery followed by RIT. Response to treatment was assessed 1 and 2 years after RIT. Odds ratio of different risk factors like age, sex, TNM stage, fTg and Anti-Tg Ab were compared between patients with and without incomplete response 1 and 2 years after treatment. Receiver operating curve analysis was used for definition of optimal fTg cut off for detection of incomplete response.

RESULTS

218 female and 55 male with DTC had negative anti-Tg antibody (mean age: 37.5±14.5 years) and analyzed separately. fTg≥33.5 ng/mL and fTg/TSH ratio of ≥0.36 had the optimal sensitivity and specificity for detection of incomplete response 1 and 2 years after treatment. fTg<33.5 ng/mL had NPV of 98.5% for exclusion of distant metastases. Patients with fTg≥33.5 ng/mL had longer "time to excellent response" (3.6±2.3 vs. 2.0±1.8 yrs) and needed more additional treatments compared to patients with fTg<33.5 ng/mL. Multivariate analysis showed that fTg was the most potent risk factor for prediction of treatment failure 1 and 2 years after RIT.

CONCLUSIONS

fTg of ≥33.5 ng/mL was the most important risk factor for prediction of treatment failure after RIT and could be included in decision algorithms regarding intensity of treatments in low/intermediate risk patients with DTC.