Theranostic Options for Radioiodine-Refractory Differentiated Thyroid Carcinoma: Recent Advances, Challenges, and Road Ahead

Low-Dose Versus High-Dose Lenvatinib in Radioiodine Refractory Differentiated Thyroid Cancer-A Real-World Safety and Efficacy Analysis

OBJECTIVE

Lenvatinib, a tyrosine kinase inhibitor, is approved for the treatment of radioiodine refractory differentiated thyroid cancer (RR-DTC) at a dose of 24 mg/day. Given its significant toxicity profile, the present study aimed to compare the safety and efficacy of initial low-dose lenvatinib to that of higher starting doses in patients with RR-DTC.

METHODS

This retrospective study included patients with RR-DTC who were classified as: Group-A: patients receiving 10mg/day, and Group-B: patients receiving ≥ 14mg/day of lenvatinib as starting dose. Safety, radiological response (as per RECIST 1.1) and progression-free survival (PFS) outcomes were analysed and compared.

RESULTS

A total of 105 patients with RR-DTC were included in this study (Group-A: 60, Group-B: 45). The study found that Group-B experienced significantly higher rates of drug interruptions (68.9% vs 48.3%, p = 0.035) and dose reductions (60% vs 11.7%; p < 0.001) compared to Group-A. Adverse events such as hand-foot skin reaction (77.8% vs 58.3%), diarrhea (28.9% vs 11.7%), hepatotoxicity (33.3-40% vs 11.7-18.3%), and electrolyte imbalance (15.6% vs 3.3%) were also more frequent in Group-B (p-values < 0.05). However, both groups showed similar objective response rates (47.1% vs 46.3%; p = 0.936) and comparable PFS outcomes (restricted mean survival time at 24 months: 22.8 vs 21.4 months, p = 0.128).

CONCLUSIONS

The study suggests that starting with lower doses of lenvatinib, followed by dose escalation if tolerated, may offer a safer approach with significantly lower rates of drug interruptions and dose reductions, with comparable efficacy in RR-DTC patients. Further validation by larger prospective trials is warranted.

Significant 99mTc-FAPI-46 Uptake in 2 Cases of TENIS Syndrome With Negative Tc-OCTREOTIDE Scan, a New Hope in Theranostic Applications

The role of fibroblast activation protein inhibitor (FAPI) as a novel radiopharmaceutical in the field of cancer diagnosis and treatment (theranostic) is still under investigation. We present 2 patients of differentiated thyroid cancer with thyroglobulin elevation and negative iodine scintigraphy (TENIS syndrome) who underwent 99mTc-OCTREOTIDE scan and 99mTc-FAPI SPECT/CT to evaluate possible sites for metastasis. 99mTc-OCTREOTIDE scan showed no remarkable uptake in these patients. On the other hand, foci of metastatic disease were found, with intense 99mTc-FAPI-46 uptake. Malignant FAPI uptake was evident in the lungs, liver, adrenal, and abdominal lymph nodes in a patient and in the lungs of another one. Due to proper uptake in diagnostic scans, these patients were recognized as a suitable candidate for treatment with 177Lu-FAPI-46.

Investigation into the Use of Surufatinib and Donafenib as Novel Multi-Kinase Inhibitors Therapeutic Agents in Managing Advanced Differentiated Thyroid Cancer: A Systematic Review

Background and Objectives: Differentiated thyroid cancer is the predominant form of endocrine cancer, with most cases being treatable. However, some patients develop resistance to traditional treatments. This review examines the use of the new multi-kinase inhibitors surufatinib and sonafenib, which target pathways related to angiogenesis and tumor growth in these patients. Methods: An extensive search of the literature was performed to find research involving these drugs in treating differentiated thyroid cancer. Four relevant studies were found, including two each for surufatinib and donafenib. Information regarding the research design, participant details, treatment methods, results on effectiveness, and side effects was collected and analyzed. Results: Surufatinib showed encouraging results, with response rates between 23.2% and 60% and progression-free survival times as long as 11.1 months. Donafenib also demonstrated improved progression-free survival times (12.9 months) compared to a placebo (6.4 months) and had response rates as high as 23.3%. Both drugs were well tolerated, with the most frequent side effects being hypertension and hand-foot syndrome. Conclusions: Both urufatinib and donafenib offer substantial benefits for patients with advanced differentiated thyroid cancer and have acceptable safety profiles. These results support their potential inclusion in treatment strategies for resistant cases, and further investigation of their clinical application is recommended.

PET Imaging of Differentiated Thyroid Cancer with TSHR-Targeted [89Zr]Zr-TR1402

Thyroid cancer is the most common endocrine cancer, with differentiated thyroid cancers (DTCs) accounting for 95% of diagnoses. While most DTC patients are diagnosed and treated with radioiodine (RAI), up to 20% of DTC patients become RAI refractory (RAI-R). RAI-R patients have significantly reduced survival rates compared to patients who remain RAI-avid. This study explores [89Zr]Zr-TR1402 as a thyroid-stimulating hormone receptor (TSHR)-targeted PET radiopharmaceutical for DTC. [89Zr]Zr-TR1402 was synthesized with a molar activity of 25.9 MBq/nmol by conjugating recombinant human TSH (rhTSH) analogue TR1402 to chelator p-SCN-Bn-deferoxamine (DFO) in a molar ratio of 3:1 (DFO/TR1402) and radiolabeling with 89Zr (t1/2 = 78.4 h, β+ = 22.7%). As TSHR is absent in commonly available DTC-derived cell lines, TSHR was reintroduced via stable transduction by delivering a lentivirus containing the full-length coding region of the human TSHR gene. Receptor-mediated uptake of [89Zr]Zr-TR1402 was evaluated in vitro in stably transduced TSHR+ and wild-type TSHR- DTC cell lines. In vivo PET imaging was performed on Days 1-3 postinjection in male and female athymic nude mice bearing TSHR+ and TSHR- xenografts, along with ex vivo biodistribution on Day 3 postinjection. In vitro uptake of 1 nM [89Zr]Zr-TR1402 was significantly higher in TSHR+ THJ529T (P < 0.0001) and FTC133 (P < 0.01) cells than in TSHR- THJ529T and FTC133 cells. This uptake was shown to be specific in both TSHR+ THJ529T (P < 0.0001) and TSHR+ FTC133 (P < 0.0001) cells by blocking uptake with 250 nm DFO-TR1402. In vivo PET imaging showed accumulation of [89Zr]Zr-TR1402 in TSHR+ tumors, which was the highest on Day 1. In the male FTC133 xenograft model, ex vivo biodistribution confirmed a significant difference (P < 0.001) in uptake between FTC133+ (1.3 ± 0.1%ID/g) and FTC133- (0.8 ± 0.1%ID/g) tumors. A significant difference (P < 0.05) in uptake was also seen in the male THJ529T xenograft model between THJ529T+ (1.8 ± 0.6%ID/g) and THJ529T- (0.8 ± 0.4%ID/g) tumors. The in vitro and in vivo accumulation of [89Zr]Zr-TR1402 in TSHR-expressing DTC cell lines support the continued preclinical optimization of this approach.

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.

Research progress of plant-derived natural products in thyroid carcinoma

Thyroid carcinoma (TC) is a prevalent malignancy of the endocrine system, with a notable rise in its detection rate in recent decades. The primary therapeutic approaches for TC now encompass thyroidectomy and radioactive iodine therapy, yielding favorable prognoses for the majority of patients. TC survivors may necessitate ongoing surveillance, remedial treatment, and thyroid hormone supplementation, while also enduring the adverse consequences of thyroid hormone fluctuations, surgical complications, or side effects linked to radioactive iodine administration, and encountering enduring physical, psychosocial, and economic hardships. In vitro and in vivo studies of natural products against TC are demonstrating the potential of these natural products as alternatives to the treatment of thyroid cancer. This therapy may offer greater convenience, affordability, and acceptability than traditional therapies. In the early screening of natural products, we mainly use a combination of database prediction and literature search. The pharmacological effects on TC of selected natural products (quercetin, genistein, apigenin, luteolin, chrysin, myricetin, resveratrol, curcumin and nobiletin), which hold promise for therapeutic applications in TC, are reviewed in detail in this article through most of the cell-level evidence, animal-level evidence, and a small amount of human-level evidence. In addition, this article explores possible issues, such as bioavailability, drug safety.