Usefulness of PET-CT scan in recurrent thyroid cancer

Abstract Introduction [18F]-FDG-PET/CT positive metastatic lesions in radioiodine-refractory differentiated thyroid cancer (RAI-R DTC) have a poor prognosis and lenvatinib represents the best therapy. We investigated the role of [ 18F]-FDG-PET/CT in the evaluation of metabolic response and prediction of the outcome of RAI-R DTC patients treated with lenvatinib. Materials and Methods Thirty-three progressive metastatic RAI-R DTC patients treated with lenvatinib were investigated at baseline and during follow-up with biochemical (Tg/TgAb), morphological (whole-body CT scan) and metabolic evaluation ([ 18F]-FDG-PET/CT). Results Nineteen of thirty-three (57.6%) patients showed the greatest metabolic response at the first [ 18F]-FDG-PET/CT scan, performed after 4 weeks of lenvatinib, while 5/33 (15.1%) patients had this response later. Moreover, 66.7% of patients had both a metabolic response at the first [ 18F]-FDG-PET/CT scan and a morphological response at the first CT scan. We observed a correlation between the metabolic response at [ 18F]-FDG-PET/CT scan performed after 4 weeks of treatment and the biochemical response at the same time in 60.6% of patients. The median overall survival (OS) was significantly longer in patients with either a metabolic response at last [ 18F]-FDG-PET/CT (40.00 vs 8.98 months) or a morphological response at last CT scan (37.22 vs 9.53 months) than in those without response. Moreover, the OS was longer in patients with a metabolic response at [ 18F]-FDG-PET/CT performed after 4 weeks of treatment (36.53 vs 11.28 months). Conclusions Our data show that [ 18F]-FDG-PET/CT can early predict the response to lenvatinib and correlates with the OS of RAI-R DTC patients treated with this drug.

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Muscarinic inhibition of salivary glands with glycopyrronium bromide does not reduce the uptake of PSMA-ligands or radioiodine

EJNMMI Research ◽

10.1186/s13550-021-00770-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

V. Mohan ◽

N. M. Bruin ◽

M. E. T. Tesselaar ◽

J. P. de Boer ◽

E. Vegt ◽

...

Keyword(s):

Prostate Cancer ◽

Thyroid Cancer ◽

Ct Scan ◽

Salivary Glands ◽

Whole Body ◽

Parotid Glands ◽

Glycopyrronium Bromide ◽

Pet Ct ◽

Significant Difference ◽

Pet Ct Scan

Abstract Rationale Salivary glands are highly perfused and express the prostate-specific membrane antigen (PSMA) receptor as well as the sodium—iodide symporter. As a consequence, treatment with 177Lu/225Ac-PSMA for prostate cancer or 131I for thyroid cancer leads to a high radiation dose in the salivary glands, and patients can be confronted with persistent xerostomia and reduced quality of life. Salivation can be inhibited using an antimuscarinic pharmaceutical, such as glycopyrronium bromide (GPB), which may also reduce perfusion. The primary objective of this work was to determine if inhibition with GPB could provide a considerable (> 30%) reduction in the accumulation of administered 123I or 68Ga-PSMA-11 in salivary glands. Methods Ten patients who already received a whole-body 68Ga-PSMA-11 PET/CT scan for (re)staging of prostate cancer underwent a repeat PET/CT scan with tracer administration at 90 min after intravenous injection of 0.2 mg GPB. Four patients in follow-up after thyroid cancer, who had been treated with one round of ablative 131I therapy with curative intent and had no signs of recurrence, received 123I planar scintigraphy at 4 h after tracer administration without GPB and a repeated scan at least one week later, with tracer administration at 30 min after intramuscular injection of 0.4 mg GPB. Tracer uptake in the salivary glands was quantified on PET and scintigraphy, respectively, and values with and without GPB were compared. Results No significant difference in PSMA uptake in the salivary glands was seen without or with GPB (Mean SULmean parotid glands control 5.57, intervention 5.72, p = 0.50. Mean SULmean submandibular glands control 6.25, intervention 5.89, p = 0.12). Three out of 4 patients showed increased 123I uptake in the salivary glands after GPB (Mean counts per pixel control 8.60, intervention 11.46). Conclusion Muscarinic inhibition of salivation with GPB did not significantly reduce the uptake of PSMA-ligands or radioiodine in salivary glands, and can be dismissed as a potential strategy to reduce toxicity from radionuclide therapies.

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Thyroid Cancer and (FDG)PET/CT Scan

Case Medical Research ◽

10.31525/ct1-nct04128631 ◽

2019 ◽

Author(s):

Keyword(s):

Thyroid Cancer ◽

Ct Scan ◽

Fdg Pet ◽

Pet Ct ◽

Fdg Pet Ct ◽

Pet Ct Scan

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Impact of 18F-FDG PET/CT on Clinical Management of Suspected Radio-Iodine Refractory Differentiated Thyroid Cancer (RAI-R-DTC)

Diagnostics ◽

10.3390/diagnostics11081430 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1430

Author(s):

Elisa Lodi Rizzini ◽

Andrea Repaci ◽

Elena Tabacchi ◽

Lucia Zanoni ◽

Valentina Vicennati ◽

...

Keyword(s):

Thyroid Cancer ◽

Ct Scan ◽

Fdg Pet ◽

Therapeutic Approach ◽

Differentiated Thyroid Cancer ◽

Whole Body ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct ◽

Pet Ct Scan

Background: As reported in the literature, [18F]-fluorodeoxyglucose positron emission tomography/computed tomography ([18F]-FDG PET/CT) provides useful qualitative and semi-quantitative data for the prognosis of advanced differentiated thyroid cancer. Instead, there is a lack of data about the real clinical impact of 18F-FDG PET/CT on the choice of the more effective therapeutic approach for advanced differentiated thyroid cancer (DTC) that starts to lose iodine avidity. The primary aim of this retrospective study was to assess how 18F-FDG PET/CT can guide the choice of the best therapeutic approach to RAI-refractory DTC (RAI-R-DTC) in patients with a doubtful iodine uptake/negative 18F-FDG PET/CT I whole-body scan after several radioactive iodine therapies (RAIT). The secondary aim was to assess the prognostic role of clinical and semi-quantitative metabolic 18F-FDG PET/CT parameters in comparison to published data. Materials and methods: A monocentric retrospective observational study was performed, reviewing the medical records of 53 patients recruited from a database of 208 patients treated at our Institution between 2011 and 2019, with advanced DTC that underwent FDG PET/CT scan for a suspected RAI-R-DTC. Selected patients had to perform a 18F-FDG PET/CT scan after the second RAIT based on a doubtful iodine uptake/negative 131 I whole-body scan and/or persistent elevated thyroglobulin levels. Metabolic response was defined according to positron emission tomography response criteria in solid tumors (PERCIST) guidelines. Standardized uptake value (SUV)max, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated. The association between metabolic features, clinical parameters and progression free survival (PFS) was assessed applying Kruskal–Wallis, chi-square-Pearson correlation tests, and Cox regression analyses when appropriate. Results: Among our sample of 53 patients (mean age 52.0 ± 19.9 years; 31 women and 22 men), 27 (51.0%) presented a positive 18F-FDG PET/CT scan: 16 (59.0%) underwent watchful waiting, 4 (15.0%) received external-beam radiation therapy (EBRT), 4 (15.0%) underwent surgery, 2 (7.4%) received another course of RAI therapy, and 1 underwent surgery + EBRT. PERCIST response was evaluated in 14/27 patients. Median follow-up was 5.8 ± 3.9 years and median PFS was 38.0 ± 21.8 months. At the last follow-up assessment, 14/53 (26.4%) demonstrated disease progression, 13/53 (24.5) persistence of structural disease, 25/53 (47%) persistence of biochemical disease, and 15/53 (28%) had an excellent response. A significant association was found between therapeutic approach, metabolic response, and final disease response evaluation, as well as a linear correlation between MTV and TLG with thyroglobulin level. Conclusions: Our Institutional experience confirmed the role of 18F-FDG PET/CT as a useful guide in the clinical management of RAI-R-DTC and obviated further unnecessary RAIT.

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