Background: Postoperative hypoparathyroidism (hypoPT) is a common complication following thyroid surgery. However, current research findings on the risk factors for post-thyroid surgery hypoPT are not entirely consistent, and the same risk factors may have different impacts on transient and permanent hypoPT. Therefore, there is a need for a comprehensive study to summarize and explore the risk factors for both transient and permanent hypoPT after thyroid surgery. Materials and methods: Two databases (PubMed and Embase) were searched from inception to 2024. The Newcastle–Ottawa Scale was used to rate study quality. Pooled odds ratios were used to calculate the relationship of each risk factor with transient and permanent hypoPT. Subgroup analyses were conducted for hypoPT with different definition-time (6 or 12 months). Publication bias was assessed using Begg’s test and Egger’s test. Results: A total of 19 risk factors from the 93 studies were included in the analysis. Among them, sex and parathyroid autotransplantation were the most frequently reported risk factors. Meta-analysis demonstrated that sex (female vs. male), cN stage, central neck dissection, lateral neck dissection, extent of central neck dissection (bilateral vs. unilateral), surgery [total thyroidectomy (TT) vs. lobectomy], surgery type (TT vs. sub-TT), incidental parathyroidectomy, and pathology (cancer vs. benign) were significantly associated with transient and permanent hypoPT. Preoperative calcium and parathyroid autotransplantation were only identified as risk factors for transient hypoPT, while preoperative PTH was a protective factor. Additionally, node metastasis and parathyroid in specimen were associated with permanent hypoPT. Conclusion: The highest risk of hypoPT occurs in female thyroid cancer patients with lymph node metastasis undergoing TT combined with neck dissection. The key to preventing postoperative hypoPT lies in the selection of surgical approach and intraoperative protection.

Background: Anaplastic thyroid carcinoma (ATC) is a rare, aggressive solid tumor with poor prognosis. Traditional treatment such as surgery, radiotherapy, and chemotherapy has limited therapeutic effects. In recent years, immunotherapy is changing the treatment pattern of them. We systematically summarize the research status and application of immunotherapy in ATC to provide clinicians and relevant researchers with a comprehensive perspective. Method: A comprehensive search of the PubMed and Embase databases identified 18 studies investigating the application of immunotherapy in ATC. These included ten cohort studies and eight case reports. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS) and Joanna Briggs Institute checklist (JBI). Subsequently, a single-proportion meta-analysis and meta-regression were performed to evaluate the efficacy of immunotherapy in ATC. Results: The favorable response rate to immunotherapy in ATC patients (33–100%) varies across cohorts, indicating substantial heterogeneity. The combination of immunotherapy with targeted therapy, as well as the use of neoadjuvant treatment, has led to improved outcomes for ATC. Single-proportion meta-analysis suggests that immunotherapy may provide clinical benefits for a subset of ATC patients (approximately one-third to one-half), but its effectiveness in controlling disease progression remains limited. Meta-regression further indicates that ATC patients with PD-L1 expression or BRAF ^V600E mutations tend to have better treatment responses. Among the 8 case reports, two patients achieved complete remission after immunotherapy, and four patients died of disease progression after immunotherapy. Mild adverse effects are common, but interstitial pneumonia is associated with poor prognosis in immunotherapy. Conclusion: Immunotherapy for ATC has demonstrated safety and efficacy in several studies, especially in patients with PD-L1 expression or BRAF ^V600E mutations. However, immune-related side effects should be carefully managed, particularly to prevent interstitial pneumonia.