Radiation Exposure and Benign Thyroid Nodules.

None required for Commentary.

Radioactive Iodine Therapy of Graves' Disease in Patients Pretreated With Methimazole Without Radioiodine Uptake for Dose Estimation.

OBJECTIVE: To assess response predictors to radioactive iodine (RAI) therapy without using thyroid uptake for dose estimate in patients pretreated with methimazole. METHODS: Retrospective analysis was performed of patients with Graves' disease treated with RAI doses determined without using uptake studies. RESULTS: In 242 patients (median age, 41.9 years; 66.1% female), initial mean free thyroxine (FT4) level was 4.7 ng/dL with an estimated thyroid size of 49.15 g. Prior to RAI therapy, average methimazole dose was 22.7 mg/day. Mean RAI dose was 737.0 ±199.4 MBq (19.9 ± 5.4 mCi). Two hundred eight patients (85.9%) responded to RAI therapy; 185 (88.9%) became hypothyroid and 23 (11.1%) became euthyroid. The majority (90.4%) responded within 6 months of therapy with a quicker response (13.9 ± 8.3 vs 17.5 ± 13.5 weeks) for those treated with doses per gram of ≥14.8 MBq (0.4 mCi). Thirty-four nonresponders had a higher initial FT4 level and larger thyroid size with a lower RAI dose per gram of thyroid tissue. In multivariate analysis, the independent response predictor to therapy was dose per gram of thyroid tissue of ≥14.8 MBq (0.4 mCi) (hazard ratio, 3.18; 95% CI, 1.1-9.7). Doses per gram of 14.8 to 18.1 MBq (0.4-0.5 mCi) achieved maximal response rate without added advantage of higher doses. Thyroid size prior to RAI therapy, FT4 levels at diagnosis, and age were inversely related to response. CONCLUSION: RAI therapy for Graves' disease without uptake studies for dose estimates is an effective treatment method. In patients pretreated with methimazole, an RAI dose per gram of thyroid tissue of ≥14.8 MBq (0.4 mCi) showed high response rate. Prospective studies are needed to confirm the viability of this simplified and cost-effective approach.

Thyroid Collars in Dental Radiology: 2021 Update.

Background: In 2013, the American Thyroid Association (ATA) issued a "Policy Statement on Thyroid Shielding During Diagnostic Medical and Dental Radiology." The recently updated National Council on Radiation Protection and Measurement Radiation Protection in Dentistry and Oral and Maxillofacial Imaging (NCRP Report No. 177) prompts this review of progress related to patient thyroid shielding since the ATA statement was published. Summary: Relevant publications appearing since the ATA statement were identified by querying PubMed for "thyroid and dental and (collar or shielding)" and substituting specific dental radiographic procedures in the search. The search was expanded by reviewing the cited papers in the PubMed-retrieved papers and by use of the Web of Science to retrieve papers citing the PubMed retrieved publications. Although many quantitative studies have appeared reflective of current dental radiographic instrumentation and practice, much more can be done to foster minimizing radiation to the thyroid. Conclusions: We list seven areas that should be pursued. Among them are harmonizing guidelines for the use of thyroid collars based on the recent studies and a comprehensive survey of current dental radiological practice patterns.

Among Individuals Irradiated for Benign Conditions in Childhood, Developing Thyroid Cancer Does Not Affect All-Cause Survival.

Background: Whether radiation-induced thyroid cancer affects survival rates has not been clearly elucidated. Survival could be affected by the thyroid cancer itself, its treatment, or by being a sign of susceptibility to other cancers. The objective of the current study was to determine if the development of thyroid cancer is associated with a differential survival in radiation-exposed individuals. Methods: We conducted a matched prospective cohort mortality follow-up study based on data from a cohort of 4296 individuals who were irradiated predominantly for enlarged tonsils during their childhood (between 1939 and 1962) and were prospectively followed since 1974. The study matched an irradiated subject who developed (was exposed to) thyroid cancer (a "case") and two irradiated subjects, who had not developed (were not exposed to) thyroid cancer ("controls") by the time of case incidence. The two controls were randomly matched to cases by sex, year of birth, age at radiation treatment, and radiation dose. Then, using a stratified Cox analysis, we compared survival time from the date of thyroid cancer diagnosis or time of selection to either date of death or the end of the observation period (December 31, 2016). Vital status and causes of death were determined using the National Death Index (1979-2016), the Social Security Death Index (1974-1979), and study files. Cause of death was categorized as cardiovascular, malignancy, or other. Results: A total of 1008 subjects were included in the analysis, including 353 thyroid cancer cases. At the end of the study period, 162 of 655 (24.7%) of individuals without thyroid cancer had died compared with 100 of 353 (28.3%) of the subjects with thyroid cancer. The hazard ratio (HR) for all-cause mortality, comparing the thyroid cancer cases to controls, was close to unity (HR = 1.01 [0.77-1.33]). HRs remained insignificant after eliminating matched sets with microcarcinomas, defined as tumor size <10 mm (HR = 1.39 [0.96-2.03]). Distribution of the causes of death taking into account age and the time of observation differed between cases and controls (p < 0.05). Neither increased cardiovascular-related nor malignancy-related mortality was associated with radiation-induced thyroid cancer. Conclusions: Among individuals irradiated for benign conditions in childhood, development of thyroid cancer was not associated with decreased all-cause survival.

Younger age negatively impacts depression-associated exacerbation of hemoglobin A1c levels in type 2 diabetes: Implications for intervention.

Adults with type 2 diabetes (T2DM) and depression are associated with higher hemoglobin A1C (HbA1C ) compared to their nondepressed counterparts. Little is known about related clinical and demographic components contributing to these differences. We examined differences in HbA1C between adults who have T2DM with and without major depression. T tests and chi-square analyses measured differences in HbA1C and clinical/demographic variables. HbA1C was statistically higher in depressed participants compared to nondepressed participants. The difference was no longer statistically significant after controlling for age. Age and HbA1C were negatively correlated across the sample and were still correlated in each group independently. The interaction of age and HbA1C was moderated by depression status. Additionally, mechanisms for diabetes severity differences were assessed using moderation analyses and Blinder-Oaxaca decomposition technique. Seventy-four percent of the mean outcome HbA1C difference between depressed and nondepressed diabetic participants was explained by age. Furthermore, age was negatively correlated with clinical variables, such as diastolic blood pressure and cholesterol. Comparing age to smoking and nonsmoking participants, smokers were statistically younger. Younger adults with T2DM may require more attention regarding self-management, particularly in the context of depression. Depression should be screened and treated among individuals with diabetes since this exacerbates diabetes severity.

Role of biomarkers in predicting the occurrence of thyroid neoplasms in radiation-exposed children.

With increasing numbers of childhood cancer survivors who were treated with radiation, there is a need to evaluate potential biomarkers that could signal an increased risk of developing thyroid cancer. We aimed to examine the relationships between thyrotropin and thyroglobulin levels and the risk of developing thyroid nodules and cancer in a cohort of radiation-exposed children. 764 subjects who were irradiated in the neck area as children were examined and followed for up to 25 years. All subjects underwent a clinical examination, measurements of thyrotropin, thyroglobulin levels and thyroid imaging. At baseline, 216 subjects had thyroid nodules and 548 did not. Of those with nodules, 176 underwent surgery with 55 confirmed thyroid cancers. During the follow-up, 147 subjects developed thyroid nodules including 22 with thyroid cancer. Thyroglobulin levels were higher in subjects with prevalent thyroid nodules (26.1 ng/mL vs 9.37 ng/mL; P < 0.001) and in those who had an initial normal examination but later developed thyroid nodules (11.2 ng/mL vs 8.87 ng/mL; P = 0.017). There was no relationship between baseline thyrotropin levels and the prevalent presence or absence of thyroid nodules, whether a prevalent neoplasm was benign or malignant, subsequent development of thyroid nodules during follow-up or whether an incident nodule was benign or malignant. In conclusion, in radiation-exposed children, higher thyroglobulin levels indicated an increased risk of developing thyroid nodules but did not differentiate between benign and malignant neoplasms. There was no association between the baseline TSH level and the risk of developing thyroid nodules or cancer.

The association between glycemic control and clinical outcomes after kidney transplantation.

OBJECTIVE: To analyze the relationship between glycemic control after renal transplantation and subsequent graft function and complications. METHODS: We conducted a retrospective chart review of 202 consecutive patients undergoing kidney transplantation to analyze the association between perioperative and chronic glycemic control and clinical outcomes of rejection, infection, and hospital readmission during the first year after kidney transplantation. RESULTS: Mean in-hospital blood glucose (BG) was 157 ± 34.5 mg/dL. Mean hemoglobin A1c (HbA1c) during the first 12 months posttransplantation was 6.84 ± 1.46%. Fiftyfour patients (27%) were treated for acute or chronic rejection, 88 (44%) for infection, and 149 (74%) patients were readmitted at least once within the first year after transplantation. There were no significant differences in the risks for rejection, infection, or readmission across the 5 mean initial inpatient BG or subsequent HbA1c quintiles. In addition, there was no significant relationship between the percentage of BG measurements that fell in the "tight control" range of 80 to 110 mg/dL for each patient and any of the outcomes. CONCLUSION: We did not find an association between glycemic control (perioperative or chronic) and the outcomes of graft rejection, infection, or hospital readmission in the first 12 months after renal transplantation. Our results suggest that "near normal" glycemic targets are not necessary for managing hyperglycemia after renal transplantation.

Lipid effects of endocrine medications.

Various alterations of lipid homeostasis have a significant role in the pathophysiology of the artherosclerotic process. The effects of usual lipid-lowering agents such as statins, fibrates, or niacin are well known, but other endocrine therapeutic agents could also affect the blood levels of various lipoproteins and, in turn, influence atheroma formation. In this review, we attempt to summarize the effect of several hormonal and non-hormonal endocrine agents on lipid metabolism, including insulin, thyroid hormone, sex hormones, glucocorticoids, growth hormone, and several anti-diabetic agents.

Size, number, and distribution of thyroid nodules and the risk of malignancy in radiation-exposed patients who underwent surgery.

CONTEXT: The chance that a thyroid nodule is malignant is higher when there is a history of childhood radiation exposure. OBJECTIVE: The objective of the study was to determine how the size of a thyroid nodule, the number of nodules, and the distribution of nodules influence the risk of cancer in irradiated patients. PATIENTS: From a cohort of 4296 radiation-exposed people, we studied the 1059 that underwent thyroid surgery. DESIGN AND OUTCOMES: We studied the association between the size, number, distribution, and rank order of thyroid nodules and the chance of malignancy. RESULTS: There were 612 malignant nodules in 358 patients and 2037 benign ones in 930 patients. There was no change in the risk that a nodule was malignant with increasing size (odds ratio 0.91/cm, P = 0.11) among the 1709 nodules that were 0.5 cm or greater. A solitary nodule had a similar likelihood of being malignant as a nodule that was one of several (18.8 vs. 17.3%), whereas patients with multiple nodules were more likely to have thyroid cancer than those with solitary nodules [30.7 vs. 18.7%; risk ratio 1.64 (1.27-2.13)]. Aspirating only the largest nodule would have missed 111 of the cancers (42%), whereas aspirating the two largest nodules would have missed 45 of the cases (17%), although none would have been 10 mm or greater. CONCLUSIONS: In radiation-exposed patients, the following conclusions were made: 1) the likelihood that a nodule is malignant is independent of nodule number and size; 2) the likelihood of cancer is increased if more than one nodule is present; 3) evaluating the two largest nodules by fine-needle aspiration would have resulted in a significant number of cases being missed but none with large cancers; and 4) more than half of the patients with thyroid cancer had multifocal tumors.

Ultrasound-detected thyroid nodules in radiation-exposed patients: changes over time.

The relationship between radiation exposure and thyroid cancer is well known, but whether all irradiated patients should have thyroid ultrasounds is unresolved. We have performed follow-up ultrasound examinations of patients in a cohort who were exposed to conventional external radiation during 1939-63 for benign conditions of the head and neck area prior to their 16th birthday. Of 54 subjects who had normal radionuclide scans in 1974-76 and were reexamined in 1996-97 by thyroid ultrasonography, 42 remained eligible and 34 agreed to participate in the present ultrasound study. After an additional 4-8 years of follow-up and using an ultrasound machine with increased resolution, we found 160 nodules (in 33 of these 34 subjects), compared with 96 nodules (in 29 of the 34 subjects) detected in the previous examination. Only four of the new nodules were > or =10 mm. Of the previously diagnosed large (> or =10 mm) nodules, four nodules in four subjects resolved; nine nodules in six subjects regressed to <10 mm; 14 nodules in 13 subjects remained at > or =10 mm. The four new large nodules appeared in four subjects, and six small nodules increased to > or =10 mm in six other subjects. The total volume of the thyroid nodules decreased in the 13 subjects on thyroid hormone (by 0.20 cm(3)) and increased in the 21 subjects who were not (by 0.34 cm(3), p < 0.05 by unpaired t-test). In summary, thyroid nodules are extremely common in irradiated subjects. Many new ones may be observed over time, but most are small and seen because of the increased resolution of ultrasound machines. Compared to patients on no medication, nodules in patients on thyroid hormone tended to regress. Since FNA of all thyroid nodules in irradiated patients is not feasible, ultrasound is useful in identifying those lesions that are growing.