Calcitonin-negative medullary thyroid carcinoma(CNMTC)is a rare subtype of medullary thyroid carcinoma,characterized by normal serum calcitonin levels,which often leads to misdiagnosis or missed diagnosis.The pathogenesis of CNMTC remains unclear and may involve impaired secretion mechanisms or assay-related false negatives.Diagnostic approaches include ultrasound-guided fine needle aspiration cytology,serum CEA and ProGRP measurements,and RET gene testing.Surgical resection remains the mainstay of treatment,while neoadjuvant therapy may be considered in selected cases.This review summarizes recent advances in the understanding,diagnosis,treatment,and prognosis of CNMTC,aiming to provide clinical guidance for better management of this challenging condition.

Objective:To investigate the clinical predictive value of Ki67 proliferation index combined with preoperative serum Ctn for postoperative biochemical cure of medullary thyroid carcinoma (MTC) .Methods:Clinical data were collected from Dec. 2008 to Dec. 2024 from 90 patients with surgically confirmed MTC at China-Japan Union Hospital of Jilin University. The optimal cut-off value for preoperative Ctn prediction of biochemical cure (171.18pg/mL) was determined by the ROC curve; the Ki67 proliferation index cut-off value was adopted from the international MTC grading system standard (5%). Patients were divided into three groups based on the above cutoff values: double-low group (Ki67 <5% and Ctn <171.18pg/mL, n=23), single-high group (Ki67 ≥5% and Ctn <171.18pg/mL or Ki67 <5% and Ctn ≥171.18pg/mL, n=49), and double-high group (Ki67 ≥5% and Ctn ≥171.18pg/mL, n=18). The Kaplan-Meier method (Log-Rank and Trend test) was used to compare the differences in biochemical cure rates between groups, and the Cox proportional risk model was used to analyze the risk factors affecting biochemical cure. Results:The correlation between preoperative Ctn and Ki67 proliferation index was not significant. The three groups differed significantly in gender, tumor distribution, tumor size, vascular invasion, N stage, TNM stage, and biochemical cure ( P<0.05), with the double-high group being significantly associated with larger tumors, later N stage and TNM stage, and lower biochemical cure ( P<0.001). Kaplan-Meier analysis showed that the biochemical cure rate in the double-high, single-high, and double-low groups showed a stepwise improvement.Cox univariate analysis showed that tumor size, N stage, TNM stage, preoperative Ctn, and Ki67 combined with Ctn were risk factors for failure to biochemically cure; multivariate analysis confirmed that the double-high group was an independent risk factor ( P<0.05). In the single-high group, the biochemical cure rate of patients in the low Ki67-high Ctn group was lower than that of the high Ki67-low Ctn group and more malignant. Ki67 had less effect on biochemical cure and disease-free survival at the low Ctn level, and Ki67 was an independent risk factor for failure to biochemically cure at the high Ctn level ( P=0.023) and was significantly associated with disease-free survival ( P=0.004) . Conclusions:Serum Ctn is more sensitive than Ki67 index in predicting biochemical cure after MTC, and the correlation between the two was weak. Ki67 proliferation index alone has limited prognostic value, but combines with preoperative Ctn significantly optimize the prognostic assessment of patients.The role of Ki67 index varied at different Ctn levels.

Objective:To investigate the clinical predictive value of Ki67 proliferation index combined with preoperative serum Ctn for postoperative biochemical cure of medullary thyroid carcinoma (MTC) .Methods:Clinical data were collected from Dec. 2008 to Dec. 2024 from 90 patients with surgically confirmed MTC at China-Japan Union Hospital of Jilin University. The optimal cut-off value for preoperative Ctn prediction of biochemical cure (171.18pg/mL) was determined by the ROC curve; the Ki67 proliferation index cut-off value was adopted from the international MTC grading system standard (5%). Patients were divided into three groups based on the above cutoff values: double-low group (Ki67 <5% and Ctn <171.18pg/mL, n=23), single-high group (Ki67 ≥5% and Ctn <171.18pg/mL or Ki67 <5% and Ctn ≥171.18pg/mL, n=49), and double-high group (Ki67 ≥5% and Ctn ≥171.18pg/mL, n=18). The Kaplan-Meier method (Log-Rank and Trend test) was used to compare the differences in biochemical cure rates between groups, and the Cox proportional risk model was used to analyze the risk factors affecting biochemical cure. Results:The correlation between preoperative Ctn and Ki67 proliferation index was not significant. The three groups differed significantly in gender, tumor distribution, tumor size, vascular invasion, N stage, TNM stage, and biochemical cure ( P<0.05), with the double-high group being significantly associated with larger tumors, later N stage and TNM stage, and lower biochemical cure ( P<0.001). Kaplan-Meier analysis showed that the biochemical cure rate in the double-high, single-high, and double-low groups showed a stepwise improvement.Cox univariate analysis showed that tumor size, N stage, TNM stage, preoperative Ctn, and Ki67 combined with Ctn were risk factors for failure to biochemically cure; multivariate analysis confirmed that the double-high group was an independent risk factor ( P<0.05). In the single-high group, the biochemical cure rate of patients in the low Ki67-high Ctn group was lower than that of the high Ki67-low Ctn group and more malignant. Ki67 had less effect on biochemical cure and disease-free survival at the low Ctn level, and Ki67 was an independent risk factor for failure to biochemically cure at the high Ctn level ( P=0.023) and was significantly associated with disease-free survival ( P=0.004) . Conclusions:Serum Ctn is more sensitive than Ki67 index in predicting biochemical cure after MTC, and the correlation between the two was weak. Ki67 proliferation index alone has limited prognostic value, but combines with preoperative Ctn significantly optimize the prognostic assessment of patients.The role of Ki67 index varied at different Ctn levels.

Calcitonin-negative medullary thyroid carcinoma(CNMTC)is a rare subtype of medullary thyroid carcinoma,characterized by normal serum calcitonin levels,which often leads to misdiagnosis or missed diagnosis.The pathogenesis of CNMTC remains unclear and may involve impaired secretion mechanisms or assay-related false negatives.Diagnostic approaches include ultrasound-guided fine needle aspiration cytology,serum CEA and ProGRP measurements,and RET gene testing.Surgical resection remains the mainstay of treatment,while neoadjuvant therapy may be considered in selected cases.This review summarizes recent advances in the understanding,diagnosis,treatment,and prognosis of CNMTC,aiming to provide clinical guidance for better management of this challenging condition.

Objective:To investigate the efficacy and prognosis of different surgical approaches in sporadic medullary thyroid carcinoma.Methods:A retrospective analysis was conducted on 101 patients with sporadic medullary thyroid carcinoma (MTC) who underwent surgical treatment at the Department of Thyroid Surgery, China-Japan Union Hospital of Jilin University, from Feb. 2009 to Nov. 2023. The patients included 36 males and 75 females, with a male-to-female ratio of 1:2.1. The median age of the patients was 47 years old, with an age range of 21 to 72 years old. The study divided participants into two groups based on their surgical methods: an observation group (78 cases) and a control group (23 cases). The observation group received surgical methods in accordance with expert consensus, while the control group did not. The study compared the efficacy and prognosis of the two groups.Results:Statistical differences were found between the two groups in terms of stage II and III in TNM staging, intraoperative frozen pathological findings, number of lymph node resections in the central group, number of lymph node metastases in the central group, number of lymph node resections in the lateral cervical region, postoperative follow-up time, and five-year postoperative serum procalcitonin (Ctn) levels ( P<0.05) .Both groups of patients obtained a significant decrease in Ctn after surgical treatment. In the observation group, Ctn was at the remission level in 57 cases (73.1%), at the stable level in 13 cases (16.7%), and at the progression level in 8 cases (10.2%), while in the control group, Ctn was at the remission level in 20 cases (86.9%), at the progression level in 3 cases (13.1%), and there were no patients at the stable level after the operation.One patient (1.3 per cent) in the observation group had a recurrence after surgery; Two patients (8.7 per cent) in the control group had a recurrence. Conclusions:Standardised and thorough surgery can maximise the clearance of metastatic lymph nodes, effectively reduce the recurrence rate, achieve better efficacy, and improve the long-term prognosis of patients without increasing the risk of surgery and postoperative complications.

In recent years, clinical applications of robotic thyroid surgery have been gradually promoted with the continuous improvement of the da Vinci robotic surgical system. Unlike traditional open surgery, robotic thyroid surgery mainly adopts remote access, which has many advantages, such as magnified high-definition 3D view and hand vibration stabilization. The rates and causes of postoperative complications differ due to different approaches, view angles, and operation sequences. This paper presents the literature on both transoral and bilateral areolar axillary approaches in robotic thyroid surgery, focusing on five common complications under both approaches, including laryngeal recurrent nerve injury and hypoparathyroidism, to provide theoretical support for the standardization of robotic thyroid surgery.

Objective:To investigate the clinical effectiveness of da Vinci robotics in thyroid surgery.Methods:304 cases of robotic thyroid surgery performed by the same experienced surgeon at the Department of Thyroid Surgery, China-Japan Union Hospital of Jilin University during the period from Apr. 3, 2020 to Nov. 5, 2021 were prospectively included, and the operation time, operation type, postoperative drainage, postoperative hospital stay, total number of lymph node dissection and number of positive lymph nodes, operation complications, and postoperative pain level of all patients were counted. The learning curve was plotted by applying the moving average method, divided into the initial stage and the mature stage, and the differences in surgical outcomes and surgical complications between the two stages were compared. SPSS 23.0 was applied for statistical analysis, and t-test and Mann-Whitney U test were used for comparison of measurement data, and χ2 test was used for comparison of count data. Result:All surgeries were completed successfully without conversion to open cases, including 29 males and 275 females, with a mean age of (33.8±8.9) years and a range of 27-41 years. The mean body mass index (BMI) was (22.9±3.6) kg/m 2 and a range of 20.5-25.4 kg/m 2. The median operative time was 140 min, the median postoperative drainage was 52.5 ml, and the median postoperative hospital stay was 3 days. The mean number of lymph nodes cleared was 4.4±3.5, and the mean number of positive lymph nodes was 0.9±1.7. The incidence of postoperative transient laryngeal nerve (RLN) injury was 3.3%, and the incidence of transient hypoparathyroidism was 0.7%. A significant decrease in operative time occurred after the 26th case and subsequently stabilized. Compared with the initial stage of the learning curve, the mature stage had a shorter operative time (146.0±36.5 vs 198.7±56.7 min, P<0.001) , a lower incidence of temporary RLN injury (2.5% vs 11.5%, P<0.05) , and a lower percentage of benign tumor surgery (12.2% vs 26.9%, P<0.05) . Conclusion:The application of robotic technology in thyroid surgery is safe and reliable, and its successful implementation should follow a corresponding learning curve, from easy to difficult, with different surgical approaches selected according to the patient’s condition, wishes, and the operator’s technical level.

Robotic surgical systems are gradually being used in minimally invasive surgery with their advantages of high-definition magnified 3D images, stable surgical field and flexible operation. The change of surgical approach and the narrow operating space in robotic thyroid surgery have made it more difficult to identify and protect the laryngeal nerve, and the application of nerve monitoring has been limited. Many researchers have attempted to improve the monitoring equipment and probe placement to make intraoperative neuromonitoring techniques work well in robotic thyroid surgery. In this paper, we seek effective ways to protect the laryngeal nerve in robotic thyroid surgery, and lay the foundation for a more minimally invasive and standardized development of this technology.