EFFECT OF BRAFV600E AND TERT PROMOTER MUTATIONS ON THYROGLOBULIN RESPONSE IN DISTANT-METASTATIC DIFFERENTIATED THYROID CANCER

Radioactive iodine refractoriness in Middle Eastern differentiated thyroid cancer: clinical outcome and risk factor analysis

Background

Radioactive iodine refractory differentiated thyroid cancer (RAIR-DTC) has received increasing attention due to its poor prognosis. However, outcomes may vary among patients with RAIR-DTC. The role of clinico-pathological and molecular prognostic factors in survival remains controversial, resulting in difficulty in selecting patients for new targeted therapies. We assessed mortality rate and DTC-specific survival in Middle Eastern RAIR-DTC to identify prognostic factors associated with survival.

Methods

This single center, retrospective study enrolled 268 patients with RAIR-DTC. Mortality rate and DTC-specific survival were analyzed to identify prognostic factors related to survival. Univariate and multivariate analysis were performed using Cox proportional hazards model.

Results

Of the 268 cases of RAIR-DTC, 40.3% (108/268) had absent 131I uptake (either on diagnostic or post-therapy whole body scan), 15.3% (41/268) had progressive disease (PD) despite 131I, 7.5% (20/268) had persistent disease despite cumulative activity of I131 of >600 mCi and 36.9% (n=99/268) developed distant metastasis. On multivariate analysis, age (more than 45 years), presence of metastatic disease and tumors harboring telomerase reverse transcriptase (TERT) promoter mutations were independent prognostic factors for poor DTC-specific survival. Subjects were divided into 3 groups according to the number of risk factors; low risk (no risk factors); intermediate (≤ 2 risk factors); and high risk (all the 3 risk factors). Ten-year DTC-specific survival rates in low, intermediate and high-risk groups were 100.0%, 92.9% and 53.6%, respectively.

Conclusions

The contribution of age greater than 45 years to RAIR-DTC mortality is impactful. Older age, presence of distant metastasis and TERT mutations could be used as early predictors of RAIR-DTC cases. The identification of prognostic factors for poor survival in RAIR-DTC may improve the selection of patients for more personalized surveillance and therapeutic modalities.

Characterizing Genetic Alterations Related to Radioiodine Avidity in Metastatic Thyroid Cancer

CONTEXT

Patients with differentiated thyroid cancer (DTC) with distant metastasis (DM) are usually not recognized as radioactive iodine (RAI)-refractory DTC in a timely manner. The elucidation of genetic features related to RAI uptake patterns may shed light on the early recognition of RAI-refractory DTC.

OBJECTIVE

This work aimed to elucidate the underlying molecular features behind different RAI uptake patterns.

METHODS

A total of 214 patients with DM-DTC were retrospectively included in the analysis. RAI uptake patterns were defined as initially RAI refractory (I-RAIR) and initially RAI avid (I-RAIA) according to the first post-treatment scan, then I-RAIA was further divided into continually RAIA (C-RAIA), partly RAIR (P-RAIR), and gradually RAIR (G-RAIR) according to subsequent scans. The molecular subtype groups-BRAFV600E mutated, RAS mutated, fusions, and others-were classified according to main driver genes status.

RESULTS

BRAF, TERT promoter, and TP53 mutations are more frequently detected in the I-RAIR pattern while RET fusions and RAS mutations are more frequent in the I-RAIA pattern. A late-hit mutation including TERT, TP53, or PIK3CA is more common in I-RAIR than that in I-RAIA (50.0% vs 26.9%, P = .001), particularly for those with RAS mutations in the I-RAIR group, always accompanied by TERT promoter. Isolated RET fusions accounts for 10% of I-RAIR. When compared among driver gene groups, BRAFV600E-mutated tumors have a higher rate of the I-RAIR pattern (64.4%) than RAS-mutated (4.5%, P < .001) and fusion-positive (20.7%, P < .001) tumors. In I-RAIA subgroups, BRAFV600E-mutated tumors have lower prevalence of the C-RAIA pattern than those with RAS mutation or fusions.

CONCLUSION

Patients with the I-RAIR pattern predominantly featured mutations of the BRAF and/or TERT promoter, of which RAS mutations were usually accompanied by late-hit mutations, while fusions mostly occurred alone.

A user-friendly nomogram for predicting radioiodine refractory differentiated thyroid cancer

BACKGROUND

The diagnosis of radioiodine refractory differentiated thyroid cancer (RAIR-DTC) is primarily based on clinical evolution and iodine uptake over the lesions, which is still time-consuming, thus urging a predictive model for timely RAIR-DTC informing. The aim of this study was to develop a nomogram model for RAIR prediction among DTC patients with distant metastases (DM).

METHODS

Data were extracted from the treatment and follow-up databases of Peking Union Medical College Hospital between 2010 and 2021. A total of 124 patients were included and divided into RAIR (n=71) and non-RAIR (n=53) according to 2015 ATA guidelines. All patients underwent total thyroidectomy followed by at least two courses of RAI treatment. Serological markers and various clinical, pathological, genetic status, and imaging factors were integrated into this study. The pre-treatment stimulated Tg and pre- and post-treatment suppressed Tg at the first and second course RAI treatment were defined as s-Tg1, s-Tg2, sup-Tg1, and sup-Tg2, respectively. Δs-Tg denoted s-Tg1/s-Tg2, and Δs-TSH denoted s-TSH1/s-TSH2. Multivariate logistic regression and correlation analysis were utilized to determine the independent predictors of RAIR. The performance of the nomogram was assessed by internal validation and receiver operating characteristic (ROC) curve, and benefit in clinical decision-making was assessed using decision curve.

RESULTS

In univariate logistic regression, nine possible risk factors were related to RAIR. Correlation analysis showed four of the above factors associated with RAIR. Through multivariate logistic regression, Δs-Tg/Δs-TSH<1.50 and age upon diagnosis were obtained to develop a convenient nomogram model for predicting RAIR. The model was internally validated and had good predictive efficacy with an AUC of 0.830, specificity of 0.830, and sensitivity of 0.755. The decision curve also showed that if the model is used for clinical decision-making when the probability threshold is between 0.23 and 0.97, the net benefit of patients is markedly higher than that of the TreatAll and TreatNone control groups.By using 1.50 as a cut-off ofΔs-Tg/Δs-TSH, differing biochemical progression among the generally so-called RAIR can be further stratified as meaningfully rapidly or slowly progressive patients (P=0.012).

CONCLUSIONS

A convenient user-friendly nomogram model was developed with good predictive efficacy for RAIR. The progression of RAIR can be further stratified as rapidly or slowly progressive by using 1.50 as a cut-off value of Δs-Tg/Δs-TSH.

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.