Optimal extent of prophylactic central neck dissection for papillary thyroid carcinoma: Comparison of unilateral versus bilateral central neck dissection

Risk factors of transient and permanent hypoparathyroidism after thyroidectomy: a systematic review and meta-analysis

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.

Total thyroidectomy versus unilateral lobectomy for unilateral multifocal papillary thyroid carcinoma: systematic review and meta‑analysis

The optimal surgical procedure(s) for unilateral multifocal papillary thyroid carcinomas is currently controversial. As such, the present study aimed to compare the efficacies of total thyroidectomy and lobectomy in patients with unilateral multifocal papillary thyroid carcinoma. A literature search of the PubMed/Medline, Embase, Web of Science, Cochrane Library, Wan Fang, and Zhi Wang databases for relevant studies, published from inception to October 31, 2022, was performed. Two researchers independently extracted data from the included studies. Lymph node metastasis, vocal fold paralysis, parathyroid injury, postoperative recurrence, and disease-free survival were evaluated. The meta-analysis included 7 studies comprising 1540 patients, of whom 496 and 1044 underwent lobectomy and total thyroidectomy, respectively. Compared with lobectomy, total thyroidectomy resulted in more vocal cord paralysis (odds ratio [OR] 0.35 [95% confidence interval (CI) 0.13 to 0.96]; P = 0.04) and parathyroid injury (OR 0.11 [95% CI 0.03-0.39]; P = 0.001) but with better disease-free survival (OR 0.21 [95% CI 0.09-0.49]; P = 0.000), although vocal cord paralysis and parathyroid injury, in large part, resolved within 1 year after surgery. In addition, there was no difference in postoperative lymph nodes metastasis (OR 0.74 [95% CI 0.13-4.21]; P = 0.737) and postoperative recurrence (OR 2.37 [95% CI 0.42-13.38]; P = 0.33). Excluding studies that deviated from the general trend, total thyroidectomy was beneficial in reducing recurrence. Compared with lobectomy, total thyroidectomy was beneficial in reducing recurrence and disease-free survival and may be considered a more optimal approach for unilateral multifocal papillary thyroid carcinoma.

Comparison of prophylactic ipsilateral and bilateral central lymph node dissection in papillary thyroid carcinoma: a meta-analysis

OBJECTIVE

The scope of surgical resection for paratracheal (level VI) lymph nodes in patients with Papillary Thyroid Carcinoma (PTC) remains debatable. The aim of our study was to evaluate the effectiveness and safety of prophylactic ipsilateral Central Neck lymph node Dissection (CND) versus bilateral CND at the time of total thyroidectomy for Clinically Node-negative (cN0) unilateral PTC.

METHODS

A systematic retrieval of electronic databases, including Pubmed, Web of Science, and the China Journal Net, was conducted from January 1990 to September 2021. Outcome data of interest included transient hypoparathyroidism, permanent hypoparathyroidism, transient Recurrent Laryngeal Nerve (RLN) injury, permanent RLN injury and local recurrence. We constructed the summary Odds Ratios (ORs) and 95% Confidence Intervals (CIs) for every study with either fixed or random effect models.

RESULTS

A full total of 1792 patients from 6 studies were enrolled. Our meta-analysis showed that transient hypoparathyroidism was significantly more frequent in bilateral CND group (OR=0.58; 95% CI 0.44-0.76). The prevalence of permanent hypoparathyroidism was significantly higher in bilateral CND group patients compared to those in ipsilateral CND group (OR=0.26; 95% CI 0.15-0.45). On the other hand, our meta-analysis indicated that there were no significant differences in the incidence of transient RLN injury, permanent RLN injury and local recurrence.

CONCLUSIONS

Compared with bilateral CND, the rate of temporary and permanent hypoparathyroidism in ipsilateral CND is lower, but the local recurrence is similar. It may be presumptuous to suggest that ipsilateral CND is an adequate treatment for cN0 unilateral PTC.

A retrospective study of factors affecting contralateral central-neck lymph node metastasis in unilateral papillary thyroid carcinoma

BACKGROUND

In 30-40% of papillary thyroid cancer patients, central neck lymph node metastasis occurs. As a result, prophylactic central neck lymph node dissection is performed. The extent of lymph node dissection and prophylactic central neck lymph node dissection is still debatable. The incidence of central neck lymph node metastasis and related factors were investigated in this study, and also the necessity of both central neck lymph node dissections.

METHODS

Between December 2017 and December 2019, 482 patients had thyroidectomy at Pusan National University Yangsan Hospital. A retrospective study of 186 patients who had a thyroidectomy with bilateral central neck lymph node dissection for unilateral thyroid carcinoma was done.

RESULTS

Ipsilateral and contralateral central neck lymph node metastasis were identified in 40.9% (76/186) and 19.3% (36/186), respectively. Male (p < 0.001), tumor size >1 cm (p = 0.047), extrathyroidal extension (p = 0.002), central neck lymph node metastases >5 (p < 0.001), lateral neck lymph node metastasis (p = 0.012), and ipsilateral central neck lymph node metastasis (p < 0.001) were associated with the contralateral central neck lymph node metastasis in univariate analysis. In a multivariate analysis, extrathyroidal extension (OR, 3.664), more than 5 central neck lymph node metastases (OR, 29.667), ipsilateral central neck lymph node metastasis (OR, 3.911), and male (OR, 5.890) were related to contralateral central neck lymph node metastasis.

CONCLUSION

Male, extrathyroidal extension, and ipsilateral central neck lymph node metastasis may be considered for contralateral prophylactic central neck lymph node dissection. In the future, it is thought that more research on the recurrence rate will be required.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Correlation of lymph node metastasis with contrast-enhanced ultrasound features, microvessel density and microvessel area in patients with papillary thyroid carcinoma

OBJECTIVE

This study aims to investigate the relationship of cervical lymph node metastasis (LNM) with contrast-enhanced ultrasound (CEUS) features, microvessel density (MVD) and microvessel area (MVA) in patients with papillary thyroid carcinoma (PTC), and to evaluate the diagnostic value of CEUS for PTC.

METHODS

A total of 108 patients diagnosed with PTC at the First Affiliated Hospital of Jinzhou Medical University from January 2016 to December 2018 were selected and underwent preoperative CEUS of the thyroid, surgical resection and postoperative histopathological examination of their resected lesion. They were divided into a lymphatic metastasis-positive group (LNM+, n = 61) and a lymphatic metastasis-negative group (LNM-, n = 47) based on their lymph node status. The CEUS quantitative parameters, MVD and MVA, were compared between the two groups, and risk factors for LNM were analyzed by univariate and multivariate logistic regression.

RESULTS

Compared with patients with in the LNM-group, the tumor diameter and the proportion of capsule contact of patients in the LNM+group were significantly greater and the patients in this group were younger. The rise time (RT), peak intensity (PI), area under the curve (AUC), MVD, and MVA were also significantly higher in the LNM+group than in the LMN-group, while there was no significant difference in time to peak (TP), mean transit time (mTT), velocity of intensity increase (IIV), and velocity of intensity decrease (IDV) between the two groups. Univariate and multivariate correlation analysis indicated that tumor size, RT, PI, AUC, MVD, and MVA were risk factors for LNM, and ROC curves further suggested that RT had the best overall predictive performance.

CONCLUSION

Tumor size, RT, PI, AUC, MVD and MVA are risk factors for LNM in PTC. In other words, CEUS is an important non-invasive and preoperative tool for evaluating PTC, with MVD and MVA identified as vital postoperative diagnostic indicators.

The clinical significance of the features of the morphological study and immunohistochemical determination of pancytokeratin in the lymph nodes of the central zone in papillary thyroid cancer

Introduction. papillary thyroid cancer is increasingly being detected at early stages when regional and distant metastases are absent per clinical examination. However, lymph nodes of the central zone can carry hidden metastases. frequency of such metastases is 22.3–46.7 %. maximally accurate identification of hidden metastases after lymph node dissection remains an important problem.

Aim. тo evaluate the effect of histological examination characteristics and immunohistochemical measurement of pancytokeratin level on frequency of detection of papillary cancer hidden metastases in regional lymph nodes of the central zone in patients with clinical stage N0 papillary cancer.

Materials and methods. The main group included 50 patients with stage ст1–2N0М0 primary papillary thyroid cancer. Dissected central lymph nodes of the patients prior to formalin fixation were extracted from the sample and inserted in individual paraffin blocks. Apart from standard histological examination, pancytokeratin level was measured immunohistochemically in the lymph nodes. The control group consisted of 200 patients for whom dissected central cell tissue was sectioned into blocks after formalin fixation. The number of lymph nodes in the dissected sample was measured by a pathomorphologist.

Results. In the main group, the number of lymph nodes in the sample varied between 6 and 37 with mean of 20.7 ± 6.8; in the control group the number was lower: 3–25, mean 9.8 ± 5.1 (р = 0.000). In the main group, hidden metastases were detected more frequently than in the control group: in 30 (60 %) and 68 (34 %) cases, respectively (р = 0.001). In 20 (40 %) patients, immunohistochemical examination showed new metastases. use of this method allowed to detect 1 to 7 additional metastases (mean 2.4 ± 1.5 lymph node lesions).

Conclusion. use of targeted dissection with extraction of lymph nodes led to significant increase in their numbers in the samples, and immunohistochemical examination allowed to detect a large number of hidden metastases in the central lymph nodes.

Pretracheal Lymph Node Subdivision in Predicting Contralateral Central Lymph Node Metastasis for Unilateral Papillary Thyroid Carcinoma: Preliminary Results

BACKGROUND

The aims of this study were to assess the clinical value of pretracheal lymph node subdivision in identifying patients with contralateral central lymph node metastasis (CLNM) and risk factors for occult contralateral CLNM in unilateral PTC.

METHODS

A total of 139 unilateral PTC patients with a clinically node-negative neck (cN0) who underwent bilateral central neck dissection (CND) were prospectively enrolled. Intraoperatively, the pretracheal region was further divided into ipsilateral and contralateral subregions. Ipsilateral and contralateral pretracheal lymph nodes (LNs) as well as other CLNs (prelaryngeal, ipsilateral paratracheal and contralateral paratracheal) were labeled separately and sent for pathological examination. Demographic and clinicopathologic variables were analyzed to identify factors predictive of contralateral CLNM.

RESULTS

Of 139 patients, bilateral CLNM was present in 37 (26.6%) patients. Contralateral pretracheal LNM was significantly associated with contralateral CLNM. In multivariate analysis, prelaryngeal LNM (P = 0.004, odds ratio = 3.457) and contralateral pretracheal LNM (P = 0.006, odds ratio = 3.362) were identified as risk factors for contralateral CLNM. Neither neck recurrence nor distant metastasis was observed within the mean follow-up duration of 9.1 ± 1.8 months.

CONCLUSIONS

In most unilateral cN0 PTCs, performing ipsilateral CND is appropriate, while patients presenting with evident nodal disease intraoperatively or preoperatively in the contralateral central neck should undergo bilateral CND. Intraoperative re-evaluation of prelaryngeal and contralateral pretracheal LNs may be helpful in determining the extent of CND.

Predictive value of ipsilateral central lymph node metastasis for contralateral central lymph node metastasis in patients with thyroid cancer: Systematic review and meta-analysis

Careful consideration of prophylactic central compartment dissection is required to ensure that its benefits outweigh its risks in the thyroid cancer. Sixteen prospective or retrospective studies were included. True positive, true negative, false positive, and false negative were extracted from each study. The diagnostic odds ratio of ipsilateral central lymph node metastasis (iCLNM) for predicting contralateral central lymph node metastasis (cCLNM) was 12.9237 (95% confidence interval [CI], 8.1595-20.4695). The area under the summary receiver operating characteristic curve was 0.854. The sensitivity, specificity, and negative predictive value were 0.8925 [0.8232-0.9368], 0.6884 [0.6311-0.7404], and 0.9802 [0.9631-0.9894], respectively. There were strong correlations between cCLNM and clinicopathologic characteristics. Ipsilateral central lymph node pathology is useful for predicting contralateral central compartment invasion in patients with thyroid cancer. In addition, clinicopathologic characteristics were associated with cCLNM in patients with unilateral thyroid cancer.

Occult contralateral central neck metastasis in papillary thyroid carcinoma with preoperatively documented ipsilateral lateral neck metastasis

BACKGROUND

This study was conducted to evaluate risk factors and long-term prognosis of contralateral central neck metastasis (CCNM) in papillary thyroid cancer (PTC) patients with ipsilateral lateral neck metastasis. We present clinical evidence to aid in surgical decision-making regarding the extent of central neck dissection (CND), focusing on separation between ipsilateral and contralateral sides.

METHODS

A total of 379 PTC patients who underwent total thyroidectomy and concomitant bilateral central neck dissection with ipsilateral lateral neck dissection (LND) at a single institution was retrospectively included between January 1997 and December 2015.

RESULTS

The median follow-up time was 83.2 months, the mean age was 44.3 years, and the mean tumor size was 1.5 cm. Among the study sample, 266 patients were female (70.2%) and 113 (29.8%) were male. Of 379 patients, CCNM was present in 34.6%. In multivariate analysis, male sex (adjusted OR = 2.46, p = 0.002), bilaterality (adjusted OR = 2.58, p = 0.004), number of metastatic ipsilateral central lymph nodes (adjusted OR = 1.15, p = 0.002), number of metastatic lateral lymph nodes (adjusted OR = 1.48, p < 0.001), and three-level metastasis (adjusted OR = 2.46, p = 0.012) were identified as risk factors of CCNM. Overall recurrence occurred in 6.0% and 11.5% of patients in the CCNM (-) group and CCNM (+) group, respectively. In addition, contralateral recurrence was observed in 1.2% patients and 0.8% patients in the CCNM (-) group and CCNM (+) group, respectively. However, CCNM did not significantly increase risk of recurrence (adjusted HR = 1.01, p = 0.981).

CONCLUSIONS

Although the probability of pathological CCNM is not negligible, CCNM was not associated with higher risk of recurrence. This study suggest that central neck dissection may be limited to the ipsilateral side, and the result regarding prognosis of CCNM may help to avoid bilateral CND so that it could have potential to minimize unnecessary surgery-related complications such as recurrent laryngeal nerve(RLN) injury or hypoparathyroidism.

Vitamin D Insufficiency Predicts Susceptibility of Parathyroid Hormone Reduction after Total Thyroidectomy in Thyroid Cancer Patients

OBJECTIVE

Given its role in the regulation of calcium and PTH levels, vitamin D was presumed as a potential predictor of postoperative hypoparathyroidism. However, the reports about their association were controversial. This study aims to reveal the relationship between preoperative vitamin D and postoperative parathyroid hormone (PTH).

METHODS

A total of 242 papillary thyroid cancer (PTC) patients who underwent total thyroidectomy (TT) during the period from June 2016 to December 2017 at our hospital were enrolled. Patients were divided into two groups, HypoP and Non-HypoP groups, based on postoperative PTH < 15.0 or ≥15.0 pg/mL, and ΔPTH₅₀+ and ΔPTH₅₀- groups, based on postoperative PTH reduction ratio ≥ 50% or <50%. Clinicopathological features and laboratory data were compared between two sets of groups.

RESULTS

Preoperative PTH level was lower in the HypoP group than in the Non-HypoP group (42.83 vs. 47.52 pg/mL, p=0.018). No significant difference of vitamin D insufficiency was found between the HypoP and Non-HypoP groups (80.8% vs. 74.1%, p=0.226). The rate of vitamin D insufficiency was higher in the ΔPTH₅₀+ group than in the ΔPTH₅₀- group (82.6% vs. 68.4%, p=0.010). By multivariate logistic regression analysis, vitamin D insufficiency was an independent predictor of postoperative PTH reduction ratio ≥ 50% (OR = 2.2, p=0.017).

CONCLUSION

Vitamin D insufficiency is not associated with postoperative PTH in PTC patients undergoing TT. However, vitamin D insufficiency is an independent predictor of postoperative PTH reduction ratio.

Transoral Endoscopic Thyroidectomy by Vestibular Approach with Central Lymph Node Dissection for Thyroid Microcarcinoma

Background: The transoral endoscopic thyroidectomy by vestibular approach (TOETVA) has been developed for thyroid microcarcinoma (TMC) treatment worldwide, with low rate of complications and excellent oncological results. However, this approach has still not been routinely performed. Thus, in this study, we aim to demonstrate the feasibility and safety of this technique in the clinical practice. Methods: In this prospective cohort study, 29 patients diagnosed TMC and clinically node negative underwent thyroidectomy and prophylactic central lymph node dissection by TOETVA. The clinicopathologic characteristics, surgical outcomes, and cosmetic results were evaluated. Results: The mean age was 34.7 ± 8.5 years. Three patients had underlying Grave's disease. Thyroid lobectomy with isthmusectomy was performed in the majority of cases (72.4%). All patients underwent prophylactic central node dissection. The mean number of retrieved central node was 7.8 ± 3.7 (3-19). Seven patients (24.1%) had lymph node metastasis in postoperative pathology. Among them, the mean number of metastatic lymph nodes was 2.1 ± 1.7 (1-5). The mean operative time was 121.2 ± 22.6 minutes. Four patients experienced transient hoarse and 1 patient had hematoma. Visual analog scale score on first postoperative day was 2.8 ± 1.4 (0-5). Most of patients were satisfied with cosmetic outcome. Conclusions: The TOETVA is new technique for TMC in Vietnam. The initial results of oncology, postoperative complications, and cosmetic supported the application of TOETVA in TMC.

Prophylactic lymph node dissection in clinically N0 differentiated thyroid carcinoma: example of personalized treatment

Considering the 'differentiated thyroid carcinoma (DTC) epidemic', the indolent nature of DTC imposes a treatment paradigm shift toward elimination of recurrence. Lymph node metastases in cervical compartments, encountered in 20-90% of DTC, are the main culprit of recurrent disease, affecting 5-30% of patients. Personalized risk-stratified cervical prophylactic lymph node dissection (PLND) at initial thyroidectomy in DTC with no clinical, sonographic or intraoperative evidence of lymph node metastases (clinically N0) has been advocated, though not unanimously. The present review dissects the controversy over PLND. Weighing the benefit yielded from PLND up against the PLND-related morbidity is so far hampered by the inconsistent profit yielded by PLND and the challenging patient selection. Advances in tailoring PLND are anticipated to empower optimal patient care.

Meta-analysis of risk factors for CCLNM in patients with unilateral cN0 PTC

BACKGROUND

In patients with papillary thyroid cancer (PTC) with clinical negative central lymph nodes (cN0), the use of prophylactic central lymph node dissection remains controversial. Contralateral central lymph node metastasis (CCLNM) occurs in 3.88–30.63% of patients with cN0 PTC. Therefore, the present meta-analysis aimed to obtain evidence for CCLNM risk factors in unilateral cN0 PTC.

MATERIALS AND METHODS

Relevant studies were identified in the PubMed, SCIE, and Wanfang databases up to Oct 31, 2019. The included patients had undergone lobectomy or total thyroidectomy with bilateral central lymph node dissection and were diagnosed pathologically with PTC. Revman 5.3 software was applied for statistical analysis.

RESULTS

Thirteen studies comprising 2449 patients were included. The factors associated with increased CCLNM risk in patients with cN0 disease were: age <45 years (odds ratio (OR) = 1.89, 95% CI = 1.43–2.49, P < 0.00001), male sex (OR = 1.67, 95% CI = 1.24–2.24, P = 0.0007), extrathyroidal extension (OR = 1.63; 95% CI = 1.17–2.28; P = 0.004), tumor size ≥1 cm (OR = 2.63, 95% CI 1.85–3.74, P < 0.00001), lymphovascular invasion (OR = 4.27, 95% CI = 2.47–7.37, P < 0.00001), and ipsilateral central lymph node metastasis (OR = 11.42, 95% CI = 5.25–24.86, P < 0.00001). However, no association was found for capsular invasion, multifocality, or Hashimoto thyroiditis.

CONCLUSION

The meta-analysis identified that age <45 years, tumor ≥1 cm, male sex, lymphovascular invasion, extrathyroidal extension, and ipsilateral central lymph node metastasis are related to CCLNM in patients with unilateral CN0 PTC. These factors should influence the use of prophylactic central lymph node dissection in this group of patients.

Surgical Outcomes and Efficacy of Isthmusectomy in Single Isthmic Papillary Thyroid Carcinoma: A Preliminary Retrospective Study

BACKGROUND AND OBJECTIVES

The optimal extent of surgery needed for isthmic papillary thyroid carcinoma (PTC) is not well-defined, although total thyroidectomy is usually recommended. This study aimed to evaluate the efficacy of isthmusectomy in the surgical treatment of isthmic PTC. Materials and Methods: We retrospectively studied 121 patients who underwent thyroidectomy with or without central neck dissection (CND) for single isthmic PTC from January 2003 to June 2019. We excluded patients who were clinically suspected to have clinically positive cervical lymph node metastasis and gross extrathyroidal extension or to have cancers at sites other than the thyroid isthmus. Patients were divided into three groups according to the extent of thyroidectomy-total thyroidectomy, lobectomy with isthmusectomy (the lobectomy group), and isthmusectomy. Clinical and pathologic characteristics, surgical outcomes, recurrence rate, and survival were analyzed. Results: Of 121 isthmic PTC patients, 28 were men and 93 were women. Total thyroidectomy, lobectomy with isthmusectomy, and isthmusectomy were performed in 70 (57.8%), 40 (33.1%), and 11 (9.1%) patients, respectively. Prophylactic CND was performed in 104 (86%) patients. In a subgroup analysis, patients who underwent total thyroidectomy showed higher postoperative hypoparathyroidism (p < 0.001) than those who underwent lobectomy and isthmusectomy. However, there were no differences in the recurrence rate or survival between the three groups. Conclusion: Thyroid isthmusectomy may be effective in the surgical treatment of small single isthmic PTC. Further studies are necessary to verify this result.

Central Compartment Nodal Bulk: A Predictor of Permanent Postoperative Hypocalcaemia

Central compartment clearance (CCC) for Papillary thyroid cancers (PTC) is one of the factors causing postoperative hypocalcaemia. We aimed to examine determinants of this major sequela. 41 patients treated for PTCs between 2014 and 2016 were studied. Surgical details, tumour and nodal characteristics, incidence of transient, temporary and permanent hypocalcaemia were noted. Central clearance was done bilaterally in 24 (58.5%) cases, ipsilaterally in 17 (41.6%). Central nodes were involved in 26 (63.4%) cases, unilaterally in 15 (36.6%), bilaterally in 11 (26.8%). Transient hypocalcaemia developed in 10 (24.4%) cases, temporary hypocalcaemia in 6 (14.6%) cases, and permanent hypocalcaemia in 2 (4.9%) cases. 17 (41%) patients were symptomatic. 9 (21.9%) patients received intravenous calcium. The only factor consistently associated with development of hypocalcaemia of all patterns, was the presence of matted central compartment nodes (p = 0.021). Matted nodes also related to a longer length of stay (p = 0.04) and requirement of intravenous calcium (p = 0.000). Extent of CCC, nodal yield, nodal positivity, perinodal extension, number of parathyroids identified, gender or pT size were not significantly associated. Symptomatic patients did not necessarily become permanently hypocalcaemic (p = 0.8). Patients requiring intravenous calcium were more likely to take oral calcium after discharge (p = 0.002). Postoperative hypocalcaemia is more likely in cases with bulky involved central nodes where extensive clearance is done. In routine CCC, even if done bilaterally, preservation of parathyroid function is possible. Permanent hypocalcaemia after CCC need not be taken as inevitable.

Risk factors for contralateral central lymph node metastasis in unilateral cN0 papillary thyroid carcinoma: A meta-analysis

BACKGROUND

Central lymph node metastasis(CLNM) is common in papillary thyroid carcinoma(PTC). LNM is related to local recurrence and adverse prognosis. The extent of prophylactic central lymph node dissection(pCLND) is not well defined. We aim to investigate the prevalence and risk factors for contralateral central lymph node metastasis (CCLNM) in unilateral clinical node-negative (cN0) PTC patients to determine the appropriate extent of pCLND.

METHODS

A systematic literature search was performed using PubMed and Embase databases until May 2018. Published studies that estimated the association between clinicopathologic factors and CCLNM were included.

RESULTS

A total of 6 studies involving 1399 patients were included. The prevalence of CCLNM was 10.9% in all patients. The pooled analysis revealed that male gender (pooled OR = 1.67, 95%CI = 1.11-2.53, p = 0.015), age<45years (pooled OR = 1.97, 95%CI = 1.37-2.85, p < 0.001), lymphovasular invasion (pooled OR = 4.23, 95%CI = 2.25-7.98, p < 0.001), extrathyroid invasion (pooled OR = 1.75, 95%CI = 1.08-2.83, p = 0.023), and ipsilateral CLNM (pooled OR = 12.26, 95%CI = 7.27-20.67, p < 0.001) were significant risk factors for CCLNM. While tumor size>1 cm (pooled OR = 3.39, 95%CI = 0.83-13.88, P = 0.090), capsular invasion (pooled OR = 1.28, 95%CI = 0.79-2.06, p = 0.313), extrathyroid extension (pooled OR = 1.49, 95%CI = 0.86-2.56, p = 0.152), and MACIS≥6 (pooled OR = 1.08, 95%CI = 0.51-2.26, p = 0.844) were not significantly associated with CCLNM.

CONCLUSIONS

Our meta-analysis identified that male gender, age<45years, lymphovasular invasion, extrathyroid invasion and ipsilateral CLNM were significant risk factors for CCLNM. These findings may guide the extent of pCLND in unilateral cN0 PTC patients.

The New TNM Staging System for Thyroid Cancer and the Risk of Disease Downstaging

In October 2016 the American Joint Committee on Cancer (AJCC) published the 8th edition of the AJCC/TNM cancer staging system and it has been introduced in clinical practice since 1st January 2018. The effect of most of the changes in the new edition was the downstaging of a significant number of patients into lower stages, reflecting their low risk of thyroid cancer-related death. One of the most relevant modification refers to the role of the microscopic extra-thyroidal tumor invasion, which is no longer considered as criterion for the classification of T3 tumors. With the present study we want to assess the impact of the changes of the new staging system and therefore we analyzed or casistic of 84 T1-T3 thyroid-cancer patients. The results of our analysis show that he downstaging of patients according to the 8th TNM edition does not necessarily reflect less aggressive disease: we actually reported 2 lymph-nodal recurrences (40%) in the five patients that were downstaged from pT3 to pT2 and the lypmh-nodal recurrence rate for stage I rises from 0% with the 7th TNM edition to 5.3% with the 8th edition.