Modified Dose of Radioactive Iodine Therapy in a Patient With Thyroid Cancer on Peritoneal Dialysis: Case Report and Review of Literature.

Thyroid malignancy is common among patients with renal impairment compared with the general population. Treatment involves surgical resection and radioactive iodine therapy (RAI) in high-risk patients. As a result of impaired iodine clearance in those with no residual kidney function, the determination of appropriate iodine dose is challenging. Evidence is lacking, and all previous reports are based on case studies with no universally accepted protocol.  We describe the case of a 30-year-old woman with end-stage renal disease on peritoneal dialysis (PD) who was diagnosed with papillary thyroid cancer while undergoing a pre-kidney transplant workup. She had a total thyroidectomy with modified radical neck dissection followed by a reduced-dose radioactive iodine therapy of 30 mCi based on her residual kidney function. Her PD prescription was adjusted to achieve a 2 L ultrafiltration daily. One year follow-up confirmed no evidence of residual nor recurrent disease. High-risk patients with differentiated thyroid malignancy require adjuvant radioactive iodine therapy. The optimal dose of RAI in the end-stage renal disease population is controversial. There are no clear guidelines available for patients with end-stage kidney disease including patients on peritoneal dialysis. Reduced dose therapy is probably effective in achieving the goals of therapy, with lower toxic risk to internal organs. Determining the appropriate schedule of each dialysis session in relation to RAI, the specific replacement prescription, and establishing a safe environment for medical staff dealing with such patients is important to consider. This article aims to highlight the need to establish a standardized protocol among patients with reduced kidney function treated with iodine therapy.

Risk of Adverse Cardiovascular Outcomes in Differentiated Thyroid Cancer Survivors: A Systematic Review and Meta-Analysis.

Introduction: Long-term cardiovascular (CV) risk is a concern for differentiated thyroid cancer (DTC) survivors. Methods: We performed a systematic review and meta-analysis evaluating the risks of CV mortality and morbidity in DTC survivors compared with the general population. Respective meta-analyses were conducted for data that were adjusted for relevant confounders and crude data. We searched five electronic databases from inception to October 2021, supplemented with a hand search. Two reviewers independently screened citations, reviewed full text articles, extracted data, and critically appraised the studies, with discrepancies resolved by a third reviewer. The primary outcome was CV mortality. Secondary outcomes included atrial fibrillation, ischemic heart disease, stroke, and heart failure. We estimated the relative risk (RR) and confidence intervals [CI] of outcomes using random-effects models (adjusted for age and gender), compared with the general population. Results: We reviewed 3409 unique citations, 65 full text articles, and included 7 studies. CV mortality risk was significantly increased in DTC survivors in one study adjusted for confounders-adjusted RR (aRR) 3.35 ([CI 1.66-6.67]; 524 DTC, 1572 controls). The risk of CV morbidity in DTC survivors, adjusted for risk factors, was estimated as follows: atrial fibrillation-aRR 1.66 [CI 1.22-2.27] (3 studies, 4428 DTC, I2 = 75%), ischemic heart disease-aRR 0.97 [CI 0.84-1.13] (2 studies, 3910 DTC, I2 = 0%), stroke-aRR 1.14 [CI 0.84-1.55] (2 studies, 3910 DTC, I2 = 69%), and heart failure-aRR 0.98 [CI 0.60-1.59] (2 studies, 3910 DTC, I2 = 79%). In meta-analyses of unadjusted data, the risks of CV mortality were not significantly increased but the CV morbidity risks were similar to adjusted data. Conclusions: There is limited evidence suggesting that DTC survivors may be at an increased risk of CV death and atrial fibrillation (after adjustment for confounders). We did not observe a significantly increased risk of ischemic heart disease, stroke, or heart failure. Most analyses were subject to significant heterogeneity and further research, with careful attention to CV risk factors, is needed to clarify CV risk in DTC survivors. Registration: PROSPERO CRD42021244743.

Myopathic dysphagia caused by thyrotoxicosis: a case report and review of the literature.

Summary: Myopathy caused by thyrotoxicosis is not uncommon. Skeletal muscles are commonly involved, but dysphagia is a rare manifestation of thyrotoxicosis. We aim to raise awareness of dysphagia caused by hyperthyroidism and review similar cases in the literature. We present a case of severe dysphagia caused by hyperthyroidism. We also summarize similar case reports in the literature. Our patient is a 77-year-old man who presented with thyrotoxicosis related to Graves' disease (GD), dysphagia to both liquid and solid food, and weight loss. Further investigations revealed severe esophageal dysphagia and a high risk for aspiration. He required the placement of a G-tube for feeding. After 8 weeks of methimazole treatment, his thyroid function normalized and his dysphagia improved significantly, leading to the removal of the feeding G-tube. We summarize 19 case reports published in the literature of hyperthyroidism leading to dysphagia. Patients with thyrotoxicosis and dysphagia are at higher risk for aspiration pneumonia and thyroid storm. Based on previous case reports, on average, approximately 3 weeks of treatment with anti-thyroidal drugs and beta-blockers is needed before patients can eat normally. We report a case of dysphagia associated with GD, which is rare and needs prompt recognition to restore euthyroid status. Dysphagia generally resolved with normalization of thyroid function. Learning points: Myopathy caused by thyrotoxicosis is not uncommon. Skeletal muscles are commonly involved, but dysphagia is a rare manifestation of thyrotoxicosis. Dysphagia due to hyperthyroidism resolves with normalization of thyroid function. Early recognition of dysphagia related to hyperthyroidism and early initiation of therapy may help reverse the dysphagia and prevent complications.

Performance of the American Thyroid Association Risk Classification in a Single Center Cohort of Pediatric Patients with Differentiated Thyroid Cancer: A Retrospective Study.

INTRODUCTION: Differentiated thyroid cancer (DTC) is the most common endocrine malignancy in children. Retrospective studies show conflicting results regarding predictors of persistent and recurrent disease after initial therapy. In 2015, the American Thyroid Association (ATA) proposed a clinical classification system to identify pediatric thyroid cancer patients at risk for persistent/recurrent disease. MATERIAL AND METHODS: We retrospectively included all patients in our registry diagnosed with papillary DTC at ≤ 18 years of age. We analyzed the prognostic performance of the ATA classification and other risk factors for predicting response to initial treatment and final outcome in pediatric DTC. RESULTS: We included 41 patients, 34 females and 7 males, diagnosed with papillary DTC at a mean (SD) age of 16.2 (1.8) years. Based on the ATA pediatric risk classification, patients were categorized as low (61%), intermediate (10%), or high risk (29%). The median follow-up period was 7.3 (1-41) years. After initial treatment, disease free status was achieved in 92%, 50%, and 42% of the low, intermediate, and high risk groups, respectively (P <0.01). At the last visit, persistent disease was present in 12%, 25%, and 33% (P=0.27). Assessing other risk factors, only the presence of distant metastases at diagnosis resulted in increased presence of persistent disease at last follow-up (P=0.03). CONCLUSION: This study supports the clinical relevance of the ATA risk classification for predicting the response to initial treatment. There was no clear prediction of long-term outcome, but this may be due to limited power caused by the small number of patients.