Risks of Hypoparathyroidism After Total Thyroidectomy in Children: A 21-Year Experience in a High-Volume Cancer Center.

BACKGROUND: Hypoparathyroidism occurs relatively frequently after thyroid surgery in children. However, few studies have reported risk factors. We aimed to identify risk factors for hypoparathyroidism that occurred after total thyroidectomy for proven or suspected malignancy in children. METHODS: Children (aged ≤ 18 years) who underwent total thyroidectomy for neoplasm or RET germline mutation at our institution between 1997 and 2018 were included. We retrospectively reviewed demographics, surgical indications, perioperative and follow-up laboratory results, pathologic results, and duration of calcium/calcitriol supplementation. Risk factors for hypoparathyroidism were identified by multivariate analysis. RESULTS: Of 184 consecutive patients, 111 had undergone surgery for neoplasm; these diseases were primarily malignancies (106, 95.5%), predominantly papillary carcinoma (103, 92.8%). The remaining 73 patients had undergone early thyroidectomy for RET germline mutation. Among all patients, 67 (36.4%) had hypoparathyroidism: 61 transient and 6 permanent. In a multivariate analysis, central neck dissection (odds ratio 4.3, 95% confidence interval 2.0-9.1) and gross extrathyroidal extension (odds ratio 4.9, 95% confidence interval 2.0-12.1) predicted overall hypoparathyroidism; however, no significant factors were associated with permanent hypoparathyroidism. Most patients with permanent hypoparathyroidism (5 of 6) had undergone therapeutic central neck dissection. When central neck dissection was performed, younger children had a higher risk of overall hypoparathyroidism. CONCLUSIONS: In pediatric total thyroidectomies, central neck dissection and gross extrathyroidal extension were major predictors for overall hypoparathyroidism. Surgeons performing thyroidectomy in such patients should be aware of the relatively high risk, preserve parathyroid tissue to the extent possible, and be conscientious regarding postoperative calcium monitoring and replacement.

AN ANALYSIS OF THE QUALITY OF THYROID CANCER WEBSITES.

Objective: This study evaluated online thyroid cancer patient information quality. This is essential, given increasing patient use of online health information. Methods: A total of 100 thyroid cancer websites, representing those patients find first, were identified using Google and two meta-search engines. Content accuracy and patient-evaluable quality markers, including attribution, currency, structure, and content comprehensiveness and readability, were assessed with a previously validated standardized rating tool, developed using design-based methods. Accuracy was defined compared to standard, peer-reviewed medical resources, UpToDate and the National Comprehensive Cancer Network. Responses to general and personal "patient" questions were evaluated for promptness and accuracy. Results: Of 100 websites, only 26% stated authorship, and 56% cited sources. Seventy-four percent had dates of creation or last update, with only half of those dates occurring within the past 2 years. Websites most often discussed the definition (94%), diagnosis (92%), and treatment (94%) of thyroid cancer, but diagnosis and treatment were also most frequently incomplete or inaccurate: diagnosis information was complete and accurate 50% of the time, and treatment 47%. Only 2% of websites were comprehensible without high school education. Of 83 websites contacted with "patient" questions, 50 replied, 48 within 1 week. Conclusion: Thyroid cancer information is widely available online, but quality varies. Sites often lack markers for patients to assess quality, and content may be difficult to understand. Information is frequently incomplete, particularly on topics important to patients, such as diagnosis and treatment. Educational resource developers may fill these gaps, and healthcare providers can direct thyroid cancer patients to reliable online resources. Abbreviation: NCCN = National Comprehensive Cancer Network.

Effect of Tumor Size and Minimal Extrathyroidal Extension in Patients with Differentiated Thyroid Cancer.

INTRODUCTION: Risk-stratified treatment strategies have become a focus in the treatment of differentiated thyroid cancer (DTC). In the 2015 American Thyroid Association treatment guidelines, adjuvant treatment with radioactive iodine (RAI) is considered in the presence of minimal extrathyroidal extension (mETE). This study aimed to investigate the prognostic significance of mETE and tumor size in patients with DTC. METHODS: A retrospective review was undertaken of 2323 consecutive patients treated surgically for T1-T3 (defined per seventh edition of the American Joint Committee on Cancer staging criteria) and M0 DTC from 2000 to 2015 at The University of Texas MD Anderson Cancer Center. Patients were divided into four groups according to the size of the tumor (≤4 cm vs. >4 cm) and the presence of mETE. Predictors of disease-free survival (DFS), disease-specific survival, locoregional failure (LRF), and distant metastatic failure (DMF) were compared using the log-rank test and Cox's proportional hazards models. RESULTS: There were only seven DTC-related deaths, limiting the clinical significance of the analysis, especially of overall and disease-specific survival. Following multivariate analysis, patients with tumors >4 cm did worse than patients with tumors ≤4 cm with respect to DFS (group 3 [>4 cm without mETE] adjusted hazard ratio (HRadj) = 2.1 [confidence interval (CI) 1.1-3.8]; group 4 [>4 cm with mETE] HRadj = 2.9 [CI 1.6-5.1]). However, patients did not differ according to DFS, regardless of the presence of mETE within each size category (group 2 [≤4 cm with mETE] vs. group 1 [≤4 cm without mETE] HRadj = 1.3 [CI 0.9-1.8]; group 4 [>4 cm without mETE] vs. group 3 [>4 cm with mETE] HRadj = 1.0 [CI 0.5-2.3]). For LRF and DMF, size but not mETE was also an independent risk factor. CONCLUSION: Tumor size, but not the presence of mETE, was an independent predictor of DFS, LRF, and DMF in DTC.

Prognostic Scoring System to Risk Stratify Parathyroid Carcinoma.

BACKGROUND: Parathyroid carcinoma is a rare endocrine malignancy that lacks an established system for risk categorization. This study evaluated a prognostic scoring system for recurrence-free survival (RFS) of patients with parathyroid carcinoma. STUDY DESIGN: Patients diagnosed and confirmed to have parathyroid carcinoma and who were treated between 1980 and 2016 at The University of Texas MD Anderson Cancer Center were studied retrospectively. Univariate and multivariate Cox proportional hazards regression analyses of RFS were conducted. A prognostic scoring system was created based on multivariate analysis. RESULTS: Sixty-eight patients were evaluated. After a median follow-up of 4.6 years, 26 patients experienced a recurrence. The Kaplan-Meier RFS rates were 85% at 1 year (95% CI 77% to 95%), 67% at 2 years (95% CI 55% to 81%), and 51% at 10 years (95% CI 36% to 72%) after initial operation. Multivariate analysis demonstrated that age older than 65 years, serum calcium level >15 mg/dL, and vascular invasion were negatively correlated with RFS rate. Combining these adverse variables into a prognostic scoring system, we stratified patients into 3 risk groups: low (0 variable; 2-year RFS rate, 93%), moderate (1 variable; 2-year RFS rate, 72%), and high (2 variables; 2-year RFS rate, 27%) (p = 0.001 [log-rank test]; concordance index, 0.70; 95% CI 0.47 to 0.92). CONCLUSIONS: A prognostic scoring system using vascular invasion, age, and serum calcium level at initial parathyroidectomy can be used to predict RFS. This categorization might be helpful for clinical decisions relative to the timing and use of adjuvant therapy. Comprehensive validation using multiple cohorts will be needed to confirm applicability.

Predictable criteria for selective, rather than routine, calcium supplementation following thyroidectomy.

OBJECTIVES: To identify patients at risk for symptomatic hypocalcemia and to make recommendations for safe, selective calcium supplementation. DESIGN: Retrospective review of consecutive patients undergoing thyroidectomy. Patients were divided into 2 groups. Group 1 (the "high-risk/calcium-yes" group) included patients who were found to have (1) postoperative symptoms of hypocalcemia (ie, tingling and numbness), (2) any postoperative serum calcium level of less than 7 mg/dL, or (3) a parathyroid hormone level of less than 3 pg/mL on postoperative day 1. Group 2 (the "low-risk/calcium-no" group) included all other patients. Demographic, operative, biochemical, and pathologic data, as well as postoperative calcium supplementation data, were recorded. Trends in serum calcium level and parathyroid hormone level were analyzed during the immediate postoperative period to identify specific factors unique to group 1. PATIENTS: A total of 156 patients who underwent a thyroidectomy. SETTING: Tertiary care center. RESULTS: Of the 156 patients reviewed, 78% were female, 70% had a malignant disease, and the median age at operation was 50 years. Thirty-four patients (22%) were in group 1, and 122 patients (78%) were in group 2. Twenty-nine (19%) patients had a parathyroid hormone level of less than 3 pg/mL within 24 hours after a thyroidectomy. Patients who underwent a central neck dissection (P = .001), had malignant disease (P = .01), or had a documented removal of the parathyroid gland (with or without autotransplantation) at operation (P = .013) were most likely to be classified into group 1. Forty-two percent of patients in group 2 had either a parathyroid hormone level of less than 6 pg/mL or a serum calcium level of less than 8 mg/dL on postoperative day 1, but all patients in group 1 who were symptomatic met these parameters. CONCLUSION: Limiting supplementation to patients with a parathyroid hormone level of less than 6 pg/mL or a serum calcium level of less than 8 mg/dL on postoperative day 1 may eliminate unnecessary calcium/vitamin D intake, phlebotomy, and follow-up assessments in up to 58% of patients undergoing thyroidectomy. Validation is required in a prospective setting.