Impact of Patient Age and Histological Type on Radioactive Iodine Avidity of Recurrent Lesions of Differentiated Thyroid Carcinoma

Predictive Factors of Radioactive Iodine Therapy Refractoriness in Patients with Differentiated Thyroid Carcinoma

Aim  Differentiated thyroid carcinoma (DTC) is the most prevalent endocrine malignancy, with radioactive iodine (RAI) therapy being a standard of care. However, RAI refractoriness, occurring in a subset of patients, significantly impacts survival rates. Understanding predictive factors for RAI refractoriness is crucial for optimizing patient management. Methods  This retrospective study analyzed data from 90 DTC patients at Ibn Sina University Hospital, Morocco. Patients were categorized into RAI-refractory (RAIR) and non-RAIR groups based on established criteria. Statistical analyses, including univariate and multivariate logistic regression, were performed to identify predictive factors of RAI refractoriness. Results  Age at the time of diagnosis ≥ 54 years, primary tumor diameter ≥ 29 mm, and distal/nodal metastasis were independent predictors of RAIR-DTC. Additionally, the oncocytic carcinoma histological subtype significantly increased the risk of refractoriness. These findings were consistent with previous studies and underscored the importance of early detection and risk stratification. Conclusion  Recognition of predictive factors for RAI refractoriness, including age, tumor size, distal/nodal metastasis, and histological subtype, facilitates early identification of high-risk patients. This enables timely intervention and personalized treatment strategies, particularly relevant in resource-limited settings. Further prospective studies are warranted to validate these findings and explore additional molecular markers for improved prediction of RAI refractoriness.

Current Advances in Radioactive Iodine-Refractory Differentiated Thyroid Cancer

BACKGROUND

Differentiated thyroid cancer (DTC) patients have an outstanding overall long-term survival rate, and certain subsets of DTC patients have a very high likelihood of disease recurrence. Radioactive iodine (RAI) therapy is a cornerstone in DTC management, but cancer cells can eventually develop resistance to RAI. Radioactive iodine-refractory DTC (RAIR-DTC) is a condition defined by ATA 2015 guidelines when DTC cannot concentrate RAI ab initio or loses RAI uptake ability after the initial therapy. The RAIR condition implies that RAI cannot reveal new met-astatic foci, so RAIR-DTC metabolic imaging needs new tracers. 18F-FDG PET/CT has been widely used and has demonstrated prognostic value, but 18F-FDG DTC avidity may remain low. Fibroblast activation protein inhibitors (FA-Pi)s, prostatic-specific membrane antigen (PSMA), and somatostatin receptor (SSTR) tracers have been proposed as theragnostic agents in experimental settings and Arg-Gly-Asp (RGD) peptides in the diagnostic trial field. Multi-targeted tyrosine kinase inhibitors are relatively new drugs approved in RAIR-DTC therapy. Despite the promising targeted setting, they relate to frequent adverse-event onset. Sorafenib and trametinib have been included in re-differentiation protocols aimed at re-inducing RAI accumulation in DTC cells. Results appear promising, but not excellent.

CONCLUSIONS

RAIR-DTC remains a challenging nosological entity. There are still controversies on RAIR-DTC definition and post-RAI therapy evaluation, with post-therapy whole-body scan (PT-WBS) the only validated criterion of response. The recent introduction of multiple diagnostic and therapeutic agents obliges physicians to pursue a multidisciplinary approach aiming to correct drug introduction and timing choice.

Clinicopathological features of differentiated thyroid carcinoma as predictors of the effects of radioactive iodine therapy

BACKGROUND

Patients with differentiated thyroid cancer (DTC) usually have an excellent prognosis; however, 5 %-15 % develop radioactive iodine-refractory (RAIR) DTC (RAIR-DTC), which has a poor prognosis and limited treatment options. The aim of the present study was to investigate the clinicopathological characteristics of RAIR-DTC in order to provide clinical evidence for timely prediction of the effects of iodine therapy.

METHODS

Clinicopathological data for 44 patients with RAIR-DTC and 50 patients with radioiodine-avid DTC (RAIA-DTC) were retrospectively analyzed. The risk factors for RAIR-DTC were evaluated and a RAIR-DTC prediction model was established.

RESULTS

RAIR-DTC showed unique clinicopathological features that differed from those of RAIA-DTC; these included age >55 years, a high-risk histological subtype, a large tumor size, a late TNM stage, calcification, distant metastasis, and more than six metastatic lymph nodes. Patients with RAIR-DTC also developed earlier tumor progression. Binary logistic regression analysis showed that distant metastasis, a high-risk histological subtype, and a maximum tumor diameter of ≥12.5 mm were independent risk factors for RAIR-DTC, and the specificity and sensitivity of a combination of these three parameters for the prediction of RAIR-DTC were 98.0 % and 56.8 %, respectively. Decision curve analysis and the calibration curve revealed that the combined prediction of these three parameters had good repeatability and accuracy.

CONCLUSION

The clinicopathological features of DTC can effectively predict the effects of iodine therapy. A combination of distant metastasis, a high-risk histological subtype, and a maximum tumor diameter of ≥12.5 mm showed significantly higher prediction accuracy.

Characteristics and immune checkpoint status of radioiodine-refractory recurrent papillary thyroid carcinomas from Ukrainian Chornobyl Tissue Bank donors

Introduction

The radioiodine-refractory (RAI-R) recurrent papillary thyroid carcinomas (PTCs) are more frequent in elderly patients and have an unfavorable prognosis. Data on the prevalence and characteristics of RAI-R recurrent PTCs in patients of young and middle age with or without a history of radiation exposure in childhood are poorly described. The aim of the current study was: i) to determine the frequency of RAI-R recurrent PTCs among donors of the Chornobyl Tissue Bank (CTB) and analyze the clinicopathological features of primary tumors (PTs), primary metastases (PMTSs), recurrent metastases (RMTSs) and risk factors for RMTS, and ii) to determine the immune checkpoint status (ICS) of the RAI-R recurrent PTCs and to assess the factors associated with ICS positivity.

Methods

Sixty RAI-R recurrent PTCs (46 exposed to radiation and 14 non-exposed, 2.5% of all cases registered with the CTB) from the Ukrainian patients aged up to 48 years were identified.

Results

The clinicopathological characteristics of the PTs moderately to weakly resembled those of the PMTS and RMTS from the same patients while the metastatic tissues were highly similar. The multivariate model of RMTS included the dominant solid-trabecular growth pattern of the PT, cystic changes, N1b metastases, and the probability of a causation (POC) of PTC by radiation as risk factors. Among these factors, the lateral PMTS (N1b) had the strongest effect. The longer period of latency (a POC component) was the second statistically significant characteristic. ICS percent agreement between the PT and RAI-R RMTS was 91.5%; 23.7% of PTs and 28.8% of RMTSs had positive ICS (positive PD-L1 tumor epithelial cells (TECs) and positive PD-L1/PD1 tumor-associated immune cells). ICS positivity of PTs was associated with pronounced oncocytic changes and high density of the p16INK4A-positive TECs in the invasive areas of PTs. In RMTSs, ICS positivity was associated with pronounced oncocytic changes and Ki-67 labeling index ≥ 4.5% of PTs, and the dominant solid-trabecular growth pattern, Ki-67 labeling index ≥ 7.6% and p16INK4A-positivity of RMTS.

Discussion

The findings are of clinical relevance and may be useful for developing individual treatment approaches for patients with RAI-R recurrent PTCs possibly involving immunotherapy.

Primary tumour iodine avidity in relation to uptake in persistent metastatic disease in papillary and poorly differentiated thyroid cancer

PURPOSE

Patients with persistent or recurrent papillary and poorly differentiated thyroid cancer can be effectively treated with radioiodine, if the tumour tissue is iodine-avid. However, iodine-avidity status is often unknown at the time of initial radioiodine treatment, limiting any adaptive approach. This study aimed to clarify the relationship between pre-therapeutic iodine avidity in primary tumour tissue, initial lymph node metastases and iodine uptake in subsequent metastases.

METHODS

Iodine avidity was prospectively assessed pre-therapeutically in 35 patients by injection of tracer amounts of iodine-131 two days prior to surgery. Iodine concentrations in resected tissue samples were measured, enabling accurate and histologically verifiable iodine avidity data for both primary tumour and initial lymph node metastases. Iodine uptake in persistent metastatic disease was assessed by review of radiology, and treatment response was examined through journal studies.

RESULTS

Out of data from 35 patients, 10 had persistent disease at presentation or during follow-up (range 19-46 months). Four patients had non-avid persistent metastatic disease, all with low iodine avidity in their primary tumours and initial lymph node metastases. Patients with low pre-therapeutic iodine avidity did not appear to have greater risk of persistent disease.

CONCLUSION

The results indicate a close link between pre-therapeutically measured iodine concentrations in primary tumours with iodine avidity of any subsequent metastases.

Lung metastasis from thyroid cancer: A case report of unusual imaging presentation of lung metastases

RATIONALE

Thyroid cancer (TC) is the most common malignancy of the head and neck and endocrine system. Distant metastases from TC are rare and are diagnosed in only 1% to 4% of patients, and these patients have a poor prognosis, which is the leading cause of TC-related deaths. There are few reports on metastatic TC in China and abroad, and even fewer reports on lung metastases from TC. We report a special patient with lung metastases of TC.

PATIENT CONCERNS

The patient is a 31-year-old female who was found to have both lung nodules during physical examination. Chest computed tomography (CT) showed that the density of both lung nodules was the same as the vascular density, considering that the possibility of vascular origin was not excluded.

DIAGNOSIS

After consultation with the whole hospital, it was considered that vascular malformations, hemangiomas, and malignant metastases were not excluded, the patient percutaneous lung biopsy had a high risk of bleeding, and thoracoscopic lobectomy could be performed in thoracic surgery to further clarify the pathology and diagnosis.

OUTCOMES

The patient underwent thoracoscopic left lower lobe wedge resection on February 24, 2021. Postoperative pathology: (left lower lung mass) metastatic carcinoma, combined with morphology and immunohistochemistry, leaning toward thyroid follicular carcinoma lung metastasis. On May 27, 2021, the patient underwent "total thyroidectomy + lymph node dissection in the right cervical VI region." Pathological examination: (right lobe and isthmus of the thyroid gland) papillary TC, follicular subtype, and classic type, with interstitial fibrosis. The patient was diagnosed with lung metastasis of TC.

LESSONS

This patient had the same CT value of lung metastases as the vascular CT value, which is relatively rare in our clinical practice and worthy of our study. The special CT imaging presentation of this TC patient with lung metastases further broadened our horizon. In clinical practice, when we encounter similar cases, we should combine more with other tests and examinations of patients to avoid misdiagnosis and missed diagnosis.

ABCA1-Mediated EMT Promotes Papillary Thyroid Cancer Malignancy through the ERK/Fra-1/ZEB1 Pathway

Papillary thyroid cancer (PTC) is the most prevalent histological type of thyroid cancer (TC) worldwide. Although tumor metastasis occurs in regional lymph nodes, distant metastasis (DM) may also occur. Radioactive iodine (RAI) therapy is an effective treatment for TC; however, resistance to RAI occurs in patients with DM. Therefore, in this study, we investigated the efficacy of DM-related biomarkers as therapeutic targets for PTC therapy. ABCA1 expression was higher in aggressive BCPAP cells than in other PTC cells in terms of migration and invasion capacity. The knockdown of ABCA1 substantially decreased the expression of the epithelial-mesenchymal transition (EMT) marker, N-cadherin, and EMT regulator (ZEB1), resulting in suppressed migration and invasion of BCPAP cells. ABCA1 knockdown also reduced ERK activity and Fra-1 expression, which correlated with the effects of an ERK inhibitor or siRNA-mediated inhibition of ERK or Fra-1 expression. Furthermore, ABCA1-knocked-down BCPAP cells suppressed cell migration and invasion by reducing Fra-1 recruitment to Zeb1 promoter; lung metastasis was not observed in mice injected with ABCA1-knocked-down cells. Overall, our findings suggest that ABCA1 regulates lung metastasis in TC cells.

Long-term management of recurrent papillary thyroid carcinoma treated with lenvatinib for over 5 years: a case report

BACKGROUND

Few reports exist of the long-term management of recurrent and progressive papillary thyroid carcinoma (PTC) with a tyrosine kinase inhibitor for over 5 years.

CASE PRESENTATION

A 57-year-old woman was referred to a psychiatric hospital for the treatment of schizophrenia. The patient had been diagnosed with a PTC at the age of 40 and subsequently underwent a left thyroid lobectomy. At 47, completion total thyroidectomy and lymph node dissection were performed and the patient assessed as radioactive iodine refractory postoperatively. External radiation therapy was performed for Rouviere lymph nodes. At 57, neck and mediastinal lymph nodes, and lung metastases had progressed, and the trachea became narrowed by para-tracheal lymph node compression. After 2 weeks of sorafenib therapy on an outpatient basis, the patient was discovered unconsciousness at home and transferred to hospital by ambulance; sorafenib therapy was stopped. The patient was diagnosed with reversible posterior leukoencephalopathy syndrome by brain magnetic resonance imaging. External radiation therapy to the site of the tracheal stenosis in the neck and mediastinum was performed. The patient's mental symptoms worsened, and she was referred to a psychiatric hospital, Kachi Memorial Hospital, in July 2015. In September, the patient's mental state stabilized and in November, after computed tomography revealed rapid disease progression, lenvatinib was commenced at a daily dose of 24 mg. Measurable solid recurrence sites were neck lymph nodes in the pre-laryngeal subcutaneous space, right lobe of the lung, and left adrenal. After 3 months, the tumors shrank in a partial response (PR). Because of several adverse events, occasional dose reductions or discontinuations of lenvatinib were sometimes necessary. Since re-starting lenvatinib, treatment with this for 51 consecutive months was achieved while maintaining a PR. Although a new bone metastasis was noted after 57 months of lenvatinib, treatment was continued for another 9 months. The patient subsequently passed away in June 2021.

CONCLUSIONS

The long-term treatment of recurrent PTC with lenvatinib was feasible, with manageable adverse events, for more than 5 years.

Avidity and Outcomes of Radioiodine Therapy for Distant Metastasis of Distinct Types of Differentiated Thyroid Cancer

CONTEXT

The recommendations for radioactive-iodine treatment (RAIT) in metastatic differentiated thyroid cancer (DTC) are mostly based in the experience with papillary histotype and do not consider the differences within the distinct types of DTC, in terms of RAIT uptake and response.

OBJECTIVE

This work aims to investigate the association between histology and RAIT avidity and response, and to evaluate whether histotype was an independent prognostic factor in progression-free survival (PFS) and disease-specific survival (DSS) after RAIT for distant metastatic disease.

METHODS

A retrospective analysis was conducted of all DTC patients who underwent RAIT for distant metastatic disease, from 2001 to 2018, at a thyroid cancer referral center. We included 126 patients: 42 (33.3%) classical variant papillary thyroid cancer (cvPTC), 45 (35.7%) follicular variant PTC (fvPTC), 17 (13.5%) follicular thyroid cancer (FTC) and 22 (17.5%) Hürthle cell carcinoma. Main outcome measures included RAIT avidity and response.

RESULTS

RAIT avidity was independently associated with histology (P < .001) and stimulated thyroglobulin (Tg) at first RAIT for distant lesions (P = .007). Avidity was lowest in HCC (13.6%), intermediate in cvPTC (21.4%), and highest in fvPTC (75.6%) and FTC (76.5%). Regarding RAIT response, HCC and FTC were not different; both showed significantly more often progression after RAIT than fvPTC and cvPTC. Histology influenced PFS (P = .014), but tumor type was not a significant prognostic factor in DSS. Instead, age at diagnosis, resection status, and stimulated Tg at the first RAIT were significantly associated with DSS.

CONCLUSION

DTC histotype influenced RAIT avidity and PFS. It is crucial to better detect the metastatic patients that may benefit the most from RAIT.

Pre-Therapeutic Measurements of Iodine Avidity in Papillary and Poorly Differentiated Thyroid Cancer Reveal Associations with Thyroglobulin Expression, Histological Variants and Ki-67 Index

Papillary thyroid cancer (PTC) and poorly differentiated thyroid cancer (PDTC) are treated with radioiodine to reduce recurrence and to treat the spread of disease. Adequate iodine accumulation in cancer tissue, iodine avidity, is important for treatment effect. This study investigated which clinical and histological tumour characteristics correlate with avidity. To quantify avidity in cancer tissue, tracer amounts of iodine-131 were given to 45 patients with cytologically confirmed thyroid cancer. At pathology grossing, representative samples of tumour and lymph nodes were taken and subjected to radioactivity quantification ex vivo to determine avidity. Afterwards, samples underwent extended pathology work-up and analysis. We found that tumoural Tg expression and Ki-67 index were correlated with avidity, whereas tumour size and pT stage were not. The histological variant of thyroid cancer was also correlated with iodine avidity. Variants associated with worse clinical prognoses displayed lower avidity than variants with better prognoses. This work provides new information on which tumours have low iodine avidity. Lower avidity in aggressive histological PTC variants may explain their overall poorer prognoses. Our findings also suggest that radioiodine dosage could be adapted to Tg expression, Ki-67 index or histological variant instead of pT stage, potentially improving the efficacy of radioiodine therapy.

Unexpected radioactive iodine accumulation on whole-body scan after I-131 ablation therapy for differentiated thyroid cancer

We retrospectively evaluated the frequency of unexpected accumulation of radioactive iodine on the post-therapy whole-body scan (Rx-WBS) after radioactive iodine (RAI) ablation therapy in patients with differentiated thyroid cancer (DTC). We searched our institutional database for Rx-WBSs of DTC patients who underwent RAI ablation or adjuvant therapy between 2012 and 2019. Patients with distant metastasis diagnosed by CT or PET/CT before therapy, and those had previously received RAI therapy were excluded. In total, 293 patients (201 female and 92 male, median age 54 years) were selected. Two nuclear medicine physicians interpreted the Rx-WBS images by determining the visual intensity of radioiodine uptake by the thyroid bed, cervical and mediastinal lymph nodes, lungs, and bone. Clinical features of the patients with and without the metastatic accumulation were compared by chi-square test and median test. Logistic regression analyses were performed to compare the association between the presence of metastatic accumulation and these clinical factors. Eighty-four of 293 patients (28.7%) showed metastatic accumulation. Patients with metastatic RAI accumulation showed a significantly higher frequency of pathological N1 (pN1) and serum thyroglobulin (Tg) > 1.5 ng/ml under TSH stimulation (p = 0.035 and p = 0.031, respectively). Logistic regression analysis indicated that a serum Tg > 1.5 ng/ml was significantly correlated with the presence of metastatic accumulation (odds ratio = 1.985; p = 0.033). In conclusion, Patients with Tg > 1.5 ng/ml were more likely to show metastatic accumulation. In addition, the presence of lymph node metastasis at the initial thyroid surgery was also associated with this unexpected metastatic accumulation.

Radioactive Iodine Therapy in Patients With Thyroid Carcinoma With Distant Metastases: A SEER-Based Study

Distant metastasis (DM) is the dominant negative prognosis for thyroid carcinoma. Radioactive iodine (RAI) therapy serves as an effective treatment for thyroid carcinoma. However, resistance to RAI occurs in patients with DMs. The present study aims to discriminate patients who may benefit from RAI. We extracted patients with thyroid cancer in the Surveillance, Epidemiology, and End Results program and analyzed thyroid cancer–specific survival after radiotherapy based on age and grade subgroups. A total of 1608 patients having DMs were eligible, including 521 (32.4%) cases with bone metastasis, 90 (5.6%) cases with brain metastasis, 158 (9.8%) cases with liver metastasis, 995 (61.9%) cases with lung metastasis, and 50 (3.1%) cases with other metastases. Advanced age, poor differentiation, follicular carcinoma, lymphatic metastasis, tumor size >10 mm, and extracapsular invasion are associated with pulmonary metastases. With respect to patients with DM, RAI therapy improved the survival in the age <45 years group and the well-/moderately differentiated group. For patients with pulmonary metastasis, RAI improved the survival in the higher grade group but did not have a strong effect in the better grade group. Our data indicate that the disparity of metastatic sites has different risk factors. Similarly, this finding indicates that RAI should be precisely applied to patients who undergo DM but are young and have well-/moderately differentiated tumors and may improve survival in pulmonary metastasis patients with poor grade tumors.

Association of the Cumulative Dose of Radioactive Iodine Therapy With Overall Survival in Patients With Differentiated Thyroid Cancer and Pulmonary Metastases

Purpose: The optimal cumulative dose of radioactive iodine therapy (RAIT) for patients with differentiated thyroid cancer (DTC) and pulmonary metastases (PM) is not known, therefore we evaluated the association between the cumulative dose of RAIT and overall survival (OS). Methods: A total of 202 patients with DTC and PM who underwent thyroidectomy and RAIT were analyzed in this study. The median cumulative dose of RAIT was 530 mCi. OS was compared with an age- and sex-matched general population from China to assess relative survival. Multivariable proportional hazards model smoothing by penalized spline was applied to identify independent predictors and examine the adjusted non-linear association of cumulative dose of RAIT and patient age with mortality. Results: The observed survival and relative survival at 10 years was 54.96 and 60.81%, respectively, with the standardized mortality ratio being 5.34. The cumulative dose of RAIT was associated with mortality in a dose-dependent fashion without an apparent cutoff point after adjustment of other variables. A linear but moderate association was found in the dose of 300 to 1,000 mCi. Cumulative dose of RAIT, patient age, diameter of pulmonary metastases, and extrapulmonary metastases were identified as independent predictors for OS. The increasing patient age was associated with mortality in a non-linear pattern, with the optimal threshold being 40 years. With advancing age, the risk of death increases rapidly in patients aged 40 years and younger, but slowly in patients over 40 years. Conclusions: RAIT should be assigned to RAI-avid patients until disease has been controlled or RAIT becomes refractory after consideration of the potential long-term side-effects. Patient age was associated with OS in a non-linear pattern, with a threshold at 40 years. Consideration of age as a binary variable could elucidate a more accurate prognosis in such patients.