A Review of TENIS Syndrome in Hospital Pulau Pinang

Role of [18F]FDG PET/CT in the management of follicular cell-derived thyroid carcinoma

Follicular cell-derived thyroid carcinomas constitute the majority of thyroid malignancies. This heterogeneous group of tumours includes well differentiated, poorly differentiated, and undifferentiated forms, which have distinct pathological features, clinical behaviour, and prognosis. Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose combined with computed tomography ([18F]FDG PET/CT) is an imaging modality used in routine clinical practice for oncological patients. [18F]FDG PET/CT has emerged as a valuable tool for identifying patients at high risk of poor clinical outcomes and for facilitating individualized clinical decision-making. The aim of this comprehensive review is to summarize current knowledge regarding the role of [18F]FDG PET/CT in primary diagnosis, treatment, and follow-up of follicular cell-derived thyroid carcinomas considering the degree of differentiation. Controversial issues, including significance of accidentally detected [18F]FDG uptake in the thyroid, the role of [18F]FDG PET/CT in the early assessment of response to molecular targeted therapies, and its prognostic value are discussed in detail.

Diagnostic Performance of [18F]TFB PET/CT Compared with Therapeutic Activity [131I]Iodine SPECT/CT and [18F]FDG PET/CT in Recurrent Differentiated Thyroid Carcinoma

[18F]tetrafluoroborate ([18F]TFB) is an emerging PET tracer with excellent properties for human sodium iodide symporter (NIS)-based imaging in patients with differentiated thyroid cancer (DTC). The aim of this study was to compare [18F]TFB PET with high-activity posttherapeutic [131I]iodine whole-body scintigraphy and SPECT/CT in recurrent DTC and with [18F]FDG PET/CT in suspected dedifferentiation. Methods: Twenty-six patients treated with high-activity radioactive [131I]iodine therapy (range, 5.00-10.23 GBq) between May 2020 and November 2022 were retrospectively included. Thyroid-stimulating hormone was stimulated by 2 injections of recombinant thyroid-stimulating hormone (0.9 mg) 48 and 24 h before therapy. Before treatment, all patients underwent [18F]TFB PET/CT 40 min after injection of a median of 321 MBq of [18F]TFB. To study tracer kinetics in DTC lesions, 23 patients received an additional scan at 90 min. [131I]iodine therapeutic whole-body scintigraphy and SPECT/CT were performed at a median of 3.8 d after treatment. Twenty-five patients underwent additional [18F]FDG PET. Two experienced nuclear medicine physicians evaluated all imaging modalities in consensus. Results: A total of 62 suspected lesions were identified; of these, 30 lesions were [131I]iodine positive, 32 lesions were [18F]TFB positive, and 52 were [18F]FDG positive. Three of the 30 [131I]iodine-positive lesions were retrospectively rated as false-positive iodide uptake. Tumor-to-background ratio measurements at the 40- and 90-min time points were closely correlated (e.g., for the tumor-to-background ratio for muscle, the Pearson correlation coefficient was 0.91; P < 0.001; n = 49). We found a significant negative correlation between [18F]TFB uptake and [18F]FDG uptake as a potential marker for dedifferentiation (Pearson correlation coefficient, -0.26; P = 0.041; n = 62). Conclusion: Pretherapeutic [18F]TFB PET/CT may help to predict the positivity of recurrent DTC lesions on [131I]iodine scans. Therefore, it may help in the selection of patients for [131I]iodine therapy. Future prospective trials for iodine therapy guidance are warranted. Lesion [18F]TFB uptake seems to be inversely correlated with [18F]FDG uptake and therefore might serve as a dedifferentiation marker in DTC.

MS. Changing Paradigm in Treatment of Differentiated Thyroid Cancer

Differentiated thyroid cancer is an indolent cancer with an excellent prognosis when treated adequately. The treatment algorithm is well established and standardized. Surgery followed by radio-iodine treatment has stood the test of time. In the last decade, the paradigm has slightly shifted with newer diagnostic approaches like stimulated thyroglobulin and anti-thyroglobulin antibodies impacting the treatment decisions. The diagnostic whole body radio-iodine scan has also got innovated with the introduction of r-TSH injection protocol wherein the scan is performed while the patient is on thyroxine thereby minimizing patient discomfort. The new RISK-based classification system has resulted in altered treatment algorithms by sub dividing patients into low-, intermediate-, and high-risk groups. There has also been identification of TWO new class of thyroid cancer patients-radio-iodine-resistant thyroid cancer and TENIS syndrome (thyroglobulin elevated negative iodine scan) patients. Both these groups posed major challenge to treatment and this resulted in incorporation of TARGETED THERAPY based on the mutations that occur in these TWO groups of patients. The introduction of Sorafenib and Lenvatinib has made significant impact on progression-free and overall survival of these patients. The introduction of THYROPET (124-I PET scan) is gaining momentum as an alternative to 123/131-I scans due to high-resolution images on PET scan increasing the detection sensitivity. All the above factors have resulted in paradigm shift in the management of differentiated thyroid cancer patients.

Clinicopathological features and outcome of thyroglobulin elevation and negative iodine scintigraphy (TENIS) patients with negative neck ultrasound: Experience from a thyroid carcinoma clinic in India

Management of differentiated thyroid carcinoma (DTC) patients with thyroglobulin (Tg) elevation and negative iodine scintigraphy (TENIS) and negative neck ultrasound scan causes considerable diagnostic and therapeutic dilemma, especially in resource-poor settings. The aim of this study was to evaluate clinicopathological features and outcome of TENIS patients with negative neck US attending a thyroid cancer clinic in India. From a DTC database of 722 containing 193 TENIS patients, subjects with negative neck US and negative Tg antibody (TgAb) were selected retrospectively and analyzed using appropriate statistical methods. The study group included 64 patients (male – 17, female – 47, mean age – 44.7 ± 12.8 years) with 54 papillary and 10 follicular thyroid carcinomas, American Thyroid Association (ATA) recurrence risk categorization (2009) – low – 16, intermediate – 28, and high – 2 0. Most of the patients became TENIS within 1 year of diagnosis with median Tg level of 6.5 ng/mL (1.2–996 ng/mL) and mean follow-up of 7.8 years. On follow-up, Tg dropped spontaneously in 27 patients, more among the low and intermediate-risk categories. For those with high or increasing Tg level, further imaging (fluorodeoxyglucose positron emission tomography/computed tomography) was done and 14 out of 18 were positive. Treatment included empiric radioactive iodine therapy-16, external beam radiation therapy (EBRT)-7, and lymph node dissection (LND)-10. A favorable outcome was seen in 36 patients and unfavorable in 28. Distant metastases were associated with unfavorable outcome and poor survival. Progression-free survival was significantly better in the Tg group of <10 at the time of TENIS (111 months) compared to the Tg group >10 (72 months). Tg level dropped spontaneously in nearly half the patients, especially if levels were <10 and more so among the low-risk category. Distant metastasis was predictive of unfavorable outcomes. Along with Tg level, the ATA risk category might help to predict clinical course and reduce unnecessary expensive imaging in resource-poor settings.

Prostate-Specific Membrane Antigen Expression in Patients With Differentiated Thyroid Cancer With Thyroglobulin Elevation and Negative Iodine Scintigraphy Using 68Ga-PSMA-HBED-CC PET/CT

PURPOSE OF THE REPORT

Prostate-specific membrane antigen (PSMA) is a member of superfamily of zinc-dependent exopeptidases that is robustly expressed in prostate cancer cells and nonprostatic solid tumor neovasculature including microvessels of thyroid tumors. Its expression in differentiated thyroid cancer (DTC) has been confirmed in many recent studies, but systematic studies exploring PSMA expression in patients with DTC with thyroglobulin elevation and negative iodine scintigraphy (TENIS) are lacking. The aim of the present study was to evaluate the role of PSMA scan in TENIS patients with DTC.

METHODS

Nine consecutive patients with DTC with proven TENIS syndrome (6 men and 3 women with age range 29-68 years and mean age of 48 years) underwent 18F-FDG PET/CT as per the institution protocol. Thereafter, they were subjected to 68Ga-PSMA-HBED-CC PET/CT as per the institution protocol within a week of FDG PET imaging. Prostate-specific membrane antigen expression (SUVmax) in the lesions was compared with 18F-FDG PET and CT scan findings.

RESULTS

In 5 of 9 patients with TENIS, the metastatic lesions showed PSMA expression. A total of 14 lesions were seen on the CT scan. Prostate-specific membrane antigen PET detected 9 of 14 lesions (64.28%) (SUVmax ranging from 10.1 to 45.67; median SUVmax of 16.31), whereas FDG PET was positive in 11 of 14 lesions (78.57%). The lesions that showed PSMA uptake was localized to bones (5 of 9) and lungs (4 of 9). Two lesions that were localized to iliac crest and acetabulum were missed on FDG PET but were seen on CT and PSMA PET scan.

CONCLUSIONS

The results of this pilot study indicate that 68Ga-HBED-CC-PSMA PET/CT demonstrates PSMA expression in TENIS patients with lesions being localized to the bones and lungs. 68Ga-PSMA PET/CT could be useful for the identification of TENIS patients who might benefit from PSMA-targeted radionuclide therapy.

Challenges in the Correct Assessment of a Case of Aggressive Thyroid Carcinoma with Synchronous Breast Cancer: A Case Report and Review of the Literature of Essential Role of Radiopharmaceuticals

Thyroid carcinoma represents a complex pathology that can still be considered a medical challenge, despite having a better prognosis and life expectancy than most other neoplasms; also the scenario of multiple malignancies involving thyroid cancer is nowadays a common reality.

MATERIALS AND METHODS

We reviewed the literature regarding the aggressive presentation of synchronous thyroid and breast cancer. In the current paper, we report the case of a 59 years-old woman, diagnosed with invasive ductal breast carcinoma and papillary thyroid carcinoma, presenting a natural history of both aggressive synchronous tumors. At the moment of hospitalization, the diagnosis was breast carcinoma with multiple secondary lesions, suggestive of lung and bone metastases, and nodular goiter.

RESULTS

Searching the literature in PUBMED with the terms "thyroid carcinoma and synchronous breast carcinoma, we found 86 studies; introducing the term "aggressive," the result included 4 studies, among which, none showed to be relevant to the terms aggressive and synchronous. A similar search was done in SCOPUS finding 92 documents and after introducing the term aggressive, the number of papers was 8, none including the literature on synchronous aggressive metastatic thyroid and breast carcinoma. A majority of imaging diagnostic tools were used in this particular medical case in order to ensure the best potential outcome. The final diagnosis was papillary thyroid carcinoma with lung and unusual multiple bone metastases and synchronous invasive ductal breast carcinoma with subcutaneous metastases.

CONCLUSION

The case illustrates the challenges in the correct assessment of oncologic patients, despite the advances in medical imaging and technologies and underlines the essential role of nuclear medicine procedures in the diagnostic and therapy protocols.