UNASSIGNED: This two-center study aimed to explore the main prognostic factors affecting the final disease status in children and adolescents with differentiated thyroid cancer (caDTC) following total thyroidectomy and radioiodine therapy (RAIT).
UNASSIGNED: All caDTC patients from two centers in the period from 2004-2022 were retrospectively included. At the last follow-up, the patients\' disease status was assessed and classified as an incomplete response (IR) or as an excellent or indeterminate response (EIDR). Then, the difference in preablation stimulated thyroglobulin (ps-Tg) levels between the two groups was compared, and the threshold for predicting IR was determined using receiver operating characteristic (ROC) analysis. Moreover, univariate and multivariate analyses were conducted to identify the factors influencing the patients\' ultimate disease outcomes.
UNASSIGNED: A total of 143 patients (98 females, 45 males; median age 16 years) were recruited. After a median follow-up of 42.9 months, 80 patients (55.9%) exhibited an EIDR, whereas 63 patients (44.1%) exhibited an IR. Patients with an IR had significantly greater ps-Tg levels than did those with an EIDR (median ps-Tg 79.2 ng/mL vs. 9.3 ng/mL, p<0.001). The ROC curve showed that ps-Tg ≥20 ng/mL was the most accurate for predicting IR at the last follow-up. According to multivariate analysis, only ps-Tg, T stage and the therapeutic response to initial RAIT were significantly associated with IR.
UNASSIGNED: In caDTC patients, the ps-Tg level, T stage, and response to initial RAIT are critical final outcome indicators.

OBJECTIVE: Radioiodine (I-131) therapy for hyperthyroidism is a well-established and safe treatment option. This study aimed to investigate the relationship between the computed tomography (CT) value and the function and volume of the thyroid gland by identifying the factors that induce changes in the CT value of patients with hyperthyroidism.
METHODS: This retrospective study evaluated 38 patients with Graves\' disease and 10 patients with Plummer disease. To obtain the mean CT value and volume of the thyroid gland, the entire thyroid gland was set as the region of interest. A test dose of 3.7 MBq I-131 was administered before initiating I-131 therapy, and the radioiodine uptake (RIU) rate was assessed after 3, 24, 96, and 168 h. An approximate curve was plotted based on the RIU values obtained, and the effective half-life (EHL) was calculated. The correlation between the mean CT value and the volume of the thyroid gland, 24-h RIU, EHL, and the free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), and TSH receptor antibody (TRAb) levels was evaluated.
RESULTS: The CT value exhibited a significant positive correlation with EHL in patients with Graves\' disease (r = 0.62, p < 0.0001) as well as patients with Plummer disease (r = 0.74, p < 0.05). However, it did not display any correlation with the remaining parameters.
CONCLUSIONS: The CT value is significantly correlated with EHL, suggesting that it reflects thyroid function and is mainly related to the factors associated with iodine discharge.

UNASSIGNED: This study aimed to investigate the risk of second primary malignancy after radioiodine (RAI) therapy in patients with thyroid cancer, using the National Health Insurance Service (NHIS) database.
UNASSIGNED: We extracted data from the NHIS database of South Korea, which covers the entire population of the nation. Risk of second primary malignancy in the thyroid cancer patients who received RAI therapy were compared with the thyroid cancer patients who received surgery only.
UNASSIGNED: Between January 1, 2004, and December 31, 2018, we identified 363,155 patients who underwent thyroid surgery due to thyroid cancer for analysis. The surgery only cohort was 215,481, and the RAI cohort was 147,674 patients. A total of 19,385 patients developed second primary malignancy (solid cancer, 18,285; hematologic cancer, 1,100). There was no significant increase in the risk of second primary malignancy in patients who received a total cumulative dose of 100 mCi or less (hazard ratio [HR], 1.013; 95% confidence interval [CI], 0.979-1.049). However, a statistically significant increase in the risk of second primary malignancy was observed in patients who received 101-200 mCi (HR, 1.214; 95% CI, 1.167-1.264), 201-300 mCi (HR, 1.422; 95% CI, 1.258-1.607), and > 300 mCi (HR, 1.693; 95% CI, 1.545-1.854).
UNASSIGNED: Total cumulative doses of 100 mCi or less of RAI can be safely administered without concerns about second primary malignancy. However, the risk of second primary malignancy increases in a dose-dependent manner, and the risk-benefit needs to be considered for doses over 100 mCi of RAI therapy.

We aimed to explore the predictive value of stimulated thyroglobulin (sTg) and pre-ablation antithyroglobulin (pa-TgAb) products for the effect of radioiodine therapy (RAIT) on TgAb-positive differentiated thyroid cancer (DTC) patients.
In this study, we enrolled 265 patients with TgAb-positive DTC who underwent RAIT after total thyroidectomy (TT). Based on the last follow-up result, the patients were divided into two groups: the excellent response (ER) group and the non-excellent response (NER) group. We analyzed the factors related to the effect of RAIT.
The ER group consisted of 197 patients. The NER group consisted of 68 patients. For the univariate analysis, we found that the maximal tumor diameter, whether with extrathyroidal extension (ETE), bilateral or unilateral primary lesion, multifocality, preoperative TgAb (preop-TgAb), pa-TgAb, sTg × pa-TgAb, initial RAIT dose, N stage, and surgical extent (modified radical neck dissection or not), showed significant differences between the ER group and NER group (all p-values <0.05). The receiver operating characteristic (ROC) curves showed that the cutoff value was 724.25 IU/ml, 424.00 IU/ml, and 59.73 for preop-TgAb, pa-TgAb, and sTg × pa-TgAb, respectively. The multivariate logistic regression analysis results indicated that pa-TgAb, sTg × pa-TgAb, initial RAIT dose, and N stage were independent risk factors for NER (all p-values <0.05). For the Kaplan-Meier analysis of disease-free survival (DFS), the median DFS of the patients with sTg × pa-TgAb < 59.73 and initial RAIT dose ≤ 100 mCi was significantly longer than that of the patients with sTg × pa-TgAb ≥ 59.73 (50.27 months vs. 48.59 months, p = 0.041) and initial RAIT dose >100 mCi (50.50 months vs. 38.00 months, p = 0.030).
We found the sTg and pa-TgAb conducts is a good predictor of the efficacy of RAIT in TgAb-positive DTC patients. It can play a very positive and important role in optimizing treatment, improving prognosis, and reducing the burden of patients.

Radioiodine (131I) is widely used in the treatment of hyperthyroidism and as an effective ablative therapy for differentiated thyroid cancer. Radioiodine (131I) constitutes 90% of the currently used therapies in the field of nuclear medicine. Here, we report the cytogenetic findings of a long-term follow-up study of 27 years on a male patient who received two rounds of radioiodine treatment within a span of 26 months between 1992 and 1994 for his papillary thyroid cancer. A comprehensive cytogenetic follow-up study utilizing cytokinesis blocked micronucleus assay, dicentric chromosome assay, genome wide translocations and inversions was initiated on this patient since the first administration of radioiodine in 1992. Frequencies of micronuclei (0.006/cell) and dicentric chromosomes (0.008/cell) detected in the current study were grossly similar to that reported earlier in 2019. The mFISH analysis detected chromosome aberrations in 8.6% of the cells in the form of both unbalanced and balanced translocations. Additionally, a clonal translocation involving chromosomes 14p; 15q was observed in 2 of the 500 cells analyzed. Out of the 500 cells examined, one cell showed a complex translocation (involving chromosomes 9, 10, and 16) besides 5 other chromosome rearrangements. Collectively, our study indicates that the past radioiodine exposure results in long-lasting chromosome damage and that the persistence of translocations can be useful for both retrospective biodosimetry and for monitoring chromosome instability in the lymphocytes of radioiodine exposed individuals.

OBJECTIVE: To compare the efficacy of low and moderate 131I activities in low-risk differentiated thyroid carcinoma (DTC) patients requiring postoperative thyroid remnant ablation in a real-world clinical setting.
METHODS: We retrospectively reviewed the records of 299 low-risk DTC patients (pT1-T2, Nx(0) Mx) who had undergone (near)-total thyroidectomy followed by 131I therapy, using either low (1.1 GBq) or moderate (2.2 GBq) radioiodine activities. The response to initial treatments was evaluated after 8-12 months, and patient responses were classified according to the 2015 American Thyroid Association guidelines.
RESULTS: An excellent response was observed in 274/299 (91.6%) patients, specifically, in 119/139 (85.6%) and 155/160 (96.9%) patients treated with low and moderate 131I activities, respectively (p = 0.029). A biochemically indeterminate or incomplete response was observed in seventeen (22.2%) patients treated with low 131I activities and three (1.8%) patients treated with moderate 131I activities (p = 0.001). Finally, five patients showed an incomplete structural response, among which three and two received low and moderate 131I activities, respectively (p = 0.654).
CONCLUSIONS: When 131I ablation is indicated, we encourage the use of moderate instead of low activities, in order to reach an excellent response in a significantly larger proportion of patients, including patients with the unexpected persistence of the disease.

The risk of toxicity attributable to radioiodine therapy (RIT) remains a subject of ongoing research, with a whole-body dose of 2 Gy proposed as a safe limit. This article evaluates the RIT-induced cytogenetic damage in two rare differentiated thyroid cancer (DTC) cases, including the first follow-up study of a pediatric DTC patient. Chromosome damage in the patient\'s peripheral blood lymphocytes (PBL) was examined using conventional metaphase assay, painting of chromosomes 2, 4, and 12 (FISH), and multiplex fluorescence in situ hybridization (mFISH). Patient 1 (female, 1.6 y.o.) received four RIT courses over 1.1 years. Patient 2 (female, 49 y.o.) received 12 courses over 6.4 years, the last two of which were examined. Blood samples were collected before and 3-4 days after the treatment. Chromosome aberrations (CA) analyzed by conventional and FISH methods were converted to a whole-body dose accounting for the dose rate effect. The mFISH method showed an increase in total aberrant cell frequency following each RIT course, while cells carrying unstable aberrations predominated in the yield. The proportion of cells containing stable CA associated with long-term cytogenetic risk remained mostly unchanged during follow-up for both patients. A one-time administration of RIT was safe, as the threshold of 2 Gy for the whole-body dose was not exceeded. The risk of side effects projected from RIT-attributable cytogenetic damage was low, suggesting a good long-term prognosis. In rare cases, such as the ones reviewed in this study, individual planning based on cytogenetic biodosimetry is strongly recommended.

Thyroid hormone withdrawal (THW) in postoperative thyroid cancer patients who need always accompanied by complications (e.g., dyslipidemia and constipation). At present, there are no effective and safe means to alleviate these complications.
We aimed to assess the oral-gut microbiota profiles in THW patients then investigate whether probiotics could alleviating alleviate THW related complications and investigate whether these therapeutic effects were associated with the oral-gut microbiota state.
Fifty eligible thyroid carcinoma patients undergoing thyroidectomy were randomly assigned to receive probiotics or placebo during THW. Complications were assessed through validated questionnaires and plasma lipid indicators. The complex probiotics preparation was composed of Bifidobacterium infantis, Lactobacillus acidophilus, Enterococcus faecalis, and Bacillus cereus.
Probiotics alleviated lack of energy, constipation, weight gain, and dry mouth and decreased the levels of fecal/serum LPS and plasma lipid indicators (total cholesterol, triglycerides, low-density lipoprotein, and apolipoprotein A) (P < 0.05). Gut and oral microbial diversity were significantly decreased after THW, while an increased microbial dysbiosis index (MDI) was observed. Probiotics distinctly restored the gut and oral microbial diversity. Increased Holdemanella, Enterococcus, and Coprococcus_2, while decreased Fusobacterium, Eubacterium_ruminantium_group, Ruminococcus_1, and Parasutterella in the gut were found after probiotics intervention. Lack of energy, constipation, weight gain, and dyslipidemia were seen to be related to the above microbiota. In addition, probiotics reduced oral Prevotella_9, Haemophilus, Fusobacterium, and Lautropia, which were positively correlated with the occurrence of dry mouth.
Probiotics reduce the incidence of complications in patients after THW, which may be related to modifying the oral and gut microbiota.
[https://clinicaltrials.gov/], identifier America Clinical Trial Registry NCT03574051.

BACKGROUND: Some female thyroid cancer survivors wish to become pregnant following their cancer treatment. Current studies have shown inconsistent results on pregnancy outcomes in these survivors; however, detailed information on the pathological type, treatment, and gestational thyroid function of these patients are not yet well documented, making the refined assessment of the influence of a history of thyroid cancer and related treatments on pregnancy outcomes challenging.
OBJECTIVE: To investigate the risk of adverse pregnancy outcomes in thyroid cancer survivors.
METHODS: This was a retrospective cohort study. We included all women aged between 19 and 45 years old who delivered between January 2019 and June 2020 in West China Second University Hospital of Sichuan University. Women with tumors other than thyroid cancer or other thyroid diseases were excluded. The included women were divided into survivors of thyroid cancer (survivors) and women without any history of thyroid disease (controls). Propensity score matching and logistic regression were used to control confounding variables.
RESULTS: All 18,332 women who met the inclusion criteria were included in the study (96 survivors of papillary thyroid cancer and 18,236 controls). After propensity score matching, 96 survivors and 192 controls were included. The survivors had higher levels of free thyroxine (15.47 [13.61-17.67] vs. 14.38 [13.20-15.81] pmol/mL; P<0.001) and higher levels of thyroid peroxidase antibodies (TPOAb) (43.55 [31.43-71.43] vs. 35.95 [28.00-48.03] U/mL; P=0.008) but similar levels of thyroid stimulating hormone (1.46 [0.56-3.15] vs. 1.36 [0.81-1.92] mIU/mL; P=0.142) than the controls. There were no significant differences in adverse pregnancy outcomes between survivors and controls. Fetal macrosomia was lower among survivors (OR: 0.077, 95% CI: 0.009-0.668. P=0.020) than controls. Additionally, survivors had reduced weight gain during pregnancy (13.0 [10.0-15.0] vs. 14.00 [11.00-16.00] kg, P=0.005) and reduced placental weight (563.0 [514.5-620.0] vs. 572.0 [520.0-650.0] g, P=0.019), albeit with small absolute differences. Thyroidectomy or radioiodine therapy did not adversely affect pregnancy outcomes.
CONCLUSIONS: A history of treated papillary thyroid cancer was not associated with adverse pregnancy outcomes.

OBJECTIVE: The objective of this study was to estimate the incidence of secondary cancers and the factors associated with their development among patients who underwent radioiodine therapy (RIT) with differentiated thyroid cancer.
METHODS: We retrospectively collected medical records for patients who underwent first RIT between January 1, 2000, and December 31, 2005, from seven tertiary hospitals in South Korea after total thyroidectomy for differentiated thyroid cancer. Cancer incidence and calculated standardized rate ratio were compared with Korean cancer incidence data. The association between the development of secondary cancers and various parameters was analyzed by Cox-proportional hazard regression.
RESULTS: A total of 3106 patients were included in this study. Mean age at the time of diagnosis of thyroid cancer was 45.7 ± 13.3 years old, and 2669 (85.9%) patients were female. The follow-up period was 11.9 ± 4.6 (range, 1.2-19.6) years. A total of 183 secondary cancers, which included 162 solid and 21 hematologic cancers, occurred in 173 patients (5.6%). There was no significant difference between solid cancer incidence in our study population who underwent RIT and the overall Korean population, but the incidence of hematologic cancers and total cancer in our study was significantly higher compared with that of the Korean population. A multivariate analysis identified independent prognostic factors for the development of secondary cancer including age at 1st RIT, male, and total cumulative dose over 200 mCi.
CONCLUSIONS: We need to assess the risk benefit for patients who receive over 200 mCi of a total cumulative dose.