As color doppler ultrasound listed as the thyroid to regular physical examination project, the positive detection rate of benign and malignant thyroid diseases has increased year by year. The population of patients after thyroid surgery is getting larger and larger, however, the research on how to replace the absent thyroid with exogenous thyroid hormone is not perfect. As the switch of thyroid hormone activation and deactivation, deiodinase plays an important role in maintaining the internal environment of human body. The expression of these enzymes will change with the different needs of each organ in the individual. In the past, many authors have made a detailed description of deiodinase in basic medicine, but the principle of action in clinical aspects is relatively lacking. In this paper, the mechanism of deiodinase was reviewed through literature reading, to explore the basic principle of deiodinase in exogenous thyroid hormone supplementation after thyroid surgery.

Surgical resection is the standard treatment for most patients with thyroid cancer(TC)and is of critical significance for the prognosis of TC.However,clarifying the surgical indications of TC,standardizing the surgical method of TC and formulating rational and personalized treatment strategies are the key to maximizing the curative effect of surgical treatment.In recent years,the global consensus on guidelines related to TC diagnosis and treatment has been rapidly updated,and comprehensive guidelines covering the whole course of the disease and suitable for China's national conditions are urgently needed to keep pace with the times.In this context,the Chinese Anti-Cancer Association(CACA)'s first guidelines for the diagnosis and treatment of thyroid cancer covering all pathologic types,"Chinese Guidelines for the Integrated Diagnosis and Treatment of Cancer-CACA Guidelines for the Diagnosis and Treatment of Thyroid Cancer,"(short as 2022 edition of CACA guidelines)was officially released in April 2022.Based on the authors'personal clinical experience,this paper will interpret the contents of the 2022 edition of CACA guidelines from differentiated TC(DTC)diagnosis,initial treatment and postoperative follow-up from a surgical perspective,explore the particularity and value of surgical treatment strategies in the entire management of TC diagnosis and treatment,and point out areas that deserve to be explored in the future.

The set of guidelines for the diagnosis and treatment of thyroid nodules and differentiated thyroid cancer (the second edition) was published in 2023 in China. Based on the first (2012) edition, the current set was revised jointly by nearly 100 experts in endocrinology, thyroid surgery, oncology, nuclear medicine, ultrasound medicine, and pathology from seven national societies for one year. The new version of the guideline is still divided into two parts, namely, thyroid nodules and differentiated thyroid cancer. The writing mode of asking clinical questions, explaining and giving recommendations is adopted, and a total of 117 recommendations are provided. This article aims to compare the variations in the differentiation of benign and malignant thyroid nodules and surgical treatment of differentiated thyroid cancer between the new and old versions from the perspective of surgery. The author's own understanding and experiences are also discussed.

With the increasing incidence of thyroid cancer, more and more thyroid operations are being performed.The relationship between parathyroid gland and thyroid gland is closed and complex, and parathyroid gland’s location is changeable and its blood supply is fragile.Hypoparathyroidism caused by the damage of parathyroid gland has become one of the common postoperative complications.The causes of injury or dysfunction of parathyroid gland are various, which are not only related to anatomical factors, including the variation in morphology, colour, quantity, location and blood supply, but also related to the operation skills of the surgeon or the use of energy devices, while the destruction of blood supply and tissue thermal damage are the main reasons.Therefore, expert mastery on the anatomical location of parathyroid gland and distribution of blood supply of parathyroid gland, careful anatomy during the operation to prevent accidental removal of parathyroid gland, rational use of energy devices to prevent mechanical damage of parathyroid gland and blood supply and thermal damage, is conducive to improving protection of parathyroid function and can reduce the occurrence of postoperative hypoparathyroidism.

Objective:To explore the impact of the clinicopathological characteristics of patients on the invasiveness of thyroid papillary carcinoma, especially the impact of Hashimoto’s thyroiditis.Methods:A retrospective analysis of the medical records of 5,018 patients with papillary thyroid carcinoma who were admitted to the Center for Thyroid Diseases of the First Affiliated Hospital of Kunming Medical University from Apr. 2012 to Dec. 2018 was conducted. Among them, 166 cases were excluded due to incomplete data, 394 cases with family history, 55 cases with hyperthyroidism or other thyroid diseases, 39 cases with other malignant tumors or history of radiotherapy and chemotherapy, and 548 cases with abnormal serum TSH (decreased or increased) . After screening, a total of 3816 cases were included in this study. Observation indicators included gender, age, tumor size, extraglandular invasion, vascular invasion, Hashimoto and serum TSH levels. The serum TSH results of the 3816 patients included in this study were all normal. The invasiveness of PTC was predicted by statistical analysis of tumor extraglandular infiltration and tumor size. The study used SPSS 23.0 statistical software for analysis, univariate analysis was made by non-parametric tests ( χ2 test and rank sum test) , multivariate analysis was made by Logistic regression and linear regression analysis, and the differences were statistically significant at P<0.05. Results:Multivariate logistic regression analysis showed that tumor size [ β=0.696, P<0.001, OR (95% CI) =2.006 (1.827-2.204) ], vascular invasion [ β=0.772, P<0.001, OR (95% CI) =2.165 (1.546-3.031) ], Hashimoto [ β=-0.303, P=0.006, OR (95% CI) =0.739 (0.596-0.915) ] had an independent effect on extraglandular infiltration. The results of linear regression analysis of tumor size showed that gender ( β=0.082, P<0.001) , age ( β=-0.134, P<0.001) , extraglandular infiltration ( β=0.268, P<0.001) , vascular invasion ( β=0.076, P<0.001) were independent influencing factors for tumor size. Conclusions:Lage tumor size and the presence of vascular invasion are independent risk factors for extraglandular invasion of PTC, and HT is protective factor. Male, age ≤45 years old, presence of extraglandular invasion and vascular invasion are independent risk factors for tumor size of PTC. The clinical significance and mechanism of the difference in the effect of Hashimoto’s thyroiditis on the extra-gland infiltration of thyroid papillary carcinoma remains to be further studied.

Objective:To evaluate the feasibility, safety and effectiveness of the active surveillance as an alternative to surgery in patients with low-risk papillary thyroid microcarcinoma(PTMC); And to explore potential surgical indicators based on characteristics of patients and medical environment.Methods:A prospective cohort study was conducted in patients with low risk PTMC and received active surveillance management( n=98). Patient adherence, non-progression surgery rates were described, cumulative incidence of tumor growth≥3 mm and tumor volume increase≥50% under ultrasonic monitoring, as well as tumor doubling rate(TDR) were evaluated. Results:A total of 98 patients were enrolled in this prospective cohort. The median age was 39(30, 45) years, and the median baseline diameter of the index tumors was 5.0(3.8, 6.8) mm, with 63.3% of tumors being≤5 mm. After a median 22(12, 44) months follow-up, tumor size growth≥3 mm and tumor volume increase≥50% occurred in 11(11.2%) and 50(51.0%) patients, and no new lymph node metastasis, distant metastasis, and death occurred. Five cases(5.1%) required delayed surgery, and other five non-progression patients opted in surgery based on their own preferences. One patient lost to follow-up. The median post-tumor progression TDRs was significantly lower than that of pre-tumor progression TDRs [size growth per year: -0.09(-0.12, 0.48) vs 0.91(0.86, 1.25), P=0.014, n=8; volume increase per year: 0.29(-0.14, 0.70) vs 1.04(0.66, 2.17), P<0.001, n=39]. After tumor size and volume progression, 62.5% and 43.6% of tumors were remained stable or shrank, respectively. Conclusions:Actived surveillance can be considered as one of the management strategies for low-risk PTMC. Given the differences in population and clinical characteristics, it should be taken in to consideration in developing active surveillance management, such as candidate criteria, follow-up strategies, and intervention indications.

Objective To probe the reasonable range of central lymph node dissections(CLNs)for papillary thyroid carcinoma (PTC) in cN0 T1/T2 by analyzing the metastasis regulations of PTC in cN0 T1/T2.Methods Data of 891 PTC patients in cN0T1/T2 cases according to the research criterion from Oct.2013 to Sep.2017 were analyzed.All the patients were under the treatment of the same group of surgeons in Department of Thyroid Surgery of the First Affiliated Hospital of the Kunming Medical University and had undergone operation of bilateral total resection of thyroid gland and central lymph node.The clinical and pathological data were collected.Univariate and multivariate analysis were used to investigate the risk factors of central neck lymph node metastasis and high volume central neck lymph node metastasis.Results ①Univariate analysis showed that gender (P=0.002),age(P=0.002),multiform(P=0.000),nodular goiter(P=0.000)and with Hashimoto's(P=0.031)had significant influence in prevalence of CLN node metastasis.Gender(P=0.010)and tumor size(P=0.000)showed significant influence in prevalence of high volume CNL node metastasis.In multivariate analysis,age (OR=0.962,OR=2.856)and nodular goiter(OR=0.969,OR=3.012)showed the independent risk factor of CNL node metastasis and high volume CNL node metastasis.②The numbers of lesion in unilateral lesion were not correlated with IpsiCLNs and Cont-CLNs metastasis (P=0.347,P=0.653).The tumor diameter was correlated with Ipsi-CLNs and ContCLNs metastasis (P=0.010,P=0.000).The tumor diameter of bilateral multifocal carcinoma was correlated with LN-prRLN-CLNs metastasis (P=0.019).The tumor diameter of left and right unilateral single focal lesion was not correlated with LN-prRLN-CLNs metastasis(P=0.684,P=0.072).Conclusions According to the study,it is recommended that the PTC in cN0 T1/T2 should routinely undergo preventive central lymph nodes dissection in the case of technical support:①Preventive overall CLND is recommended for unilateral non-microscopic carcinoma and bilateral multiform carcinoma,especially in those older than 55.②For patients with unilateral single or multifocal microscopic carcinoma,only ipsilateral central lymph nodes dissection can be considered.③ Generally,routine dissection is not necessary for the lymph nodes of the right recurrent laryngeal nerve in the central region of the neck.However,for bilateral non-small cancers and right non-small cancers,LN-prRLN-CLNs dissection is recommended.

Objective: To evaluate the application of the central lymph node dissection (CLND) for papillary thyroid carcinoma (PTC) in cN0 T1/T2. Methods: Retrospective analysis of 532 cases with PTC in cN0 T1/T2 who underwent CLND between October 2014 and September 2016 in the Department of Thyroid Surgery, the First Affiliated Hospital of the Kunming Medical University. The incidence of central lymph node (CLN) metastasis and risk factors were analyzed. Results: CLN metastasis rates: 41.2% (42/102) in males vs 34.9% (150/430) in females, P=0.252; 33.9% (116/342) in single focal carcinoma vs 40.4% (74/183) in multifocal carcinoma, P=0.157; 44.0% (125/284) in patients with 45 years old or less vs 27.0% (67/248) in patients more than 45 years old, P=0.000; 30.3% (113/373) in microcarcinoma vs 50.9% (81/159) in non-microcarcinoma, P=0.000.In unilateral lesions, ipsilateral CLN metastasis was correlated with the tumor diameter (P=0.012), but not with the number of lesions (P=0.653). also contralateral CLN metastasis was correlated with the tumor diameter (P=0.000), but not with the number of lesions (P=0.815). For the left or right unilateral single focal lesion, the tumor diameter was not correlated with the metastasis of the posterior to right recurrent laryngeal nerve central lymph nodes (LN-prRLN-CLN) (P=0.652, P=0.088). But in bilateral multifocal carcinoma the tumor diameter was correlated with metastasis of LN-prRLN-CLN (P=0.039). Conclusions Prophylactic CLND is reasonable for PTC in cN0 T1/T2. A bilateral CLND should be conducted for patients with bilateral multi-focus cancer and unilateral or bilateral non-microcarcinoma, especially in patients more than 45 years old. For unilateral single focal microcarcinoma on the right, the content of CLND should be from laryngeal nerve on right center to posterior branche; for unilateral single focal microcarcinoma on the left side, the left CLND should be conducted. An ipsilateral CLND can be considered in patients with unilateral multifocal microcarcinoma, and generally a routine dissection of the LN-prRLN-CLN is not required, however for bilateral non-microcarcinoma and the the non-microcarcinoma on the right side, the LN-prRLN-CLN dissection should be conducted.

Objective: To investigate the anatomical characteristics of the parathyroid lymphatic system and the mechanism of the"negative development"of the carbon nanoparticles for parathyroid gland in thyroidectomy.Methods:This retrospective study used parathyroid tissue samples from patients that were obtained from archival records in the pathology department,including 45 cases of normal parathyroid gland tissues that were accidentally resected in thyroidectomy,10 cases of parathyroid adenomas,and 7 cases of parathyroid carcinoma.Ten cases of normal thyroid tissues were selected as positive control.Immunohistochemistry was performed using the antibodies specific for lymphatic endothelium,such as D2-40 and LYVE-1,and antibodies specific for vascular endothelial cell such as CD31 and CD34,to distinguish them from each other.Results:A total of 62 parathyroid glands samples were stained with vas-cular markers CD31,CD34 and lymphatic markers D2-40,LYVE-1 respectively(partial samples were stained unsuccessfully).Vascular vessels in the CD31 staining group were detected in 50 of 58 examined glands and the positive rate was 86.2%.In the CD34 staining group,positive rate was 100%(60/60).The positive cells were found in the central,periphery and vascular hilum of the glands.Howev-er,lymph vessels in the D2-40 staining group were detected from 17 out of 59 examined glands,with the positive rate of 28.8%;In the LYVE-1 staining group,positive rate was 39.6%(23/58).The positive cells were found in the membrane or vascular hilum,less frequent or undetectable in the central portion.Conclusions:Most of the parathyroid glands of adults might lack a lymphatic network.Only a few adult parathyroid glands had minority lymph vessels,and these lymphatics generally localized at the membrane area or in the vas-cular hilum, which could be one of the main and anatomical mechanisms resulting in drainage failure or obstruction of carbon nanoparticles and thus in parathyroid"negative development."

Objective To study the effect of temporary in vitro preservation of parathyroid on the activity of cells in the process of parathyroid auto-transplantation and function of postoperative in order to improve the survival rate of transplantation.Methods (1)Experimental rabbits for the study were randomly divided into three groups:group A,group B,group C,with 8 rabbits in each group.Then we remove the bilateral inferior parathyroid,in group A,the parathyroid glands were immediately formaldehyde-fixed;in group B and group C,the parathyroid glands were placed in normal saline in 4 ℃ and in room temperature (22-24 ℃) for 30 minutes respectively and then fixed;HE staining was performed on the left parathyroid glands to observe the morphology of the cells;Electron microscopic examination of the right parathyroid glands were performed to observe the ultrastructural changes of the cells.(2)Experimental rabbits were randomly divided into three groups:group D group E and group F,with 8 rabbits in each group,after total thyroidectomy,the double inferior parathyroid glands were took out,in group D,the parathyroid glands were immediately transplanted in bilateral anterior cervical muscles;in group E and group F,the parathyroid glands were placed in normal saline 4 ℃ and in room temperature (22-24 ℃) for 30 minutes respectively and then transplanted.All animals were monitored of serum calcium and PTH on preoperative 1 d and postoperative 1 d,3 d,5 d,7 d;the parathyroid was took out for HE staining to observed survival of parathyroid tissue and pathology damage when 7d after operation.Results (1) The normal parathyroid gland is mainly dominated by the chief cells,the nucleus of the chief cell was round and centered under electron microscope;there were no significant change in the morphology of parathyroid cells,and the mitoehondria of the cells were slightly swollen under 4 ℃;but the parathyroid gland cells were slightly swollen and partially vacuole degeneration,the morphology of the nucleus was irregular,and the mitochondria were extremely swollen and deformed,and the ridge was broken under room temperature.(2)three groups of rabbits after transplantation of parathyroid,serum calcium and PTH decreased significantly,and increased gradually,there was significant difference on the 7th day after the operaion between the two groups (P＜0.05);(3)in group D,the normal parathyroid cells densely distributed in the anterior cervical muscle tissue;in group E,A large number of parathyroid cells survived in muscle tissue,with some vacuolated;in group F,only part of healthy parathyroid ceils scattered in the muscle.Conclusion Parathyroid should be preserved in 4 ℃ normal saline during the operation,and the transplant should be completed in 30 minutes as far as possible.