The risk of central nodal metastasis based on prognostic factors of the differentiated thyroid carcinoma: a systematic review and meta-analysis study

BACKGROUND AND AIM

Despite improving the 10-year disease-free-survival, prophylactic central neck dissection (pCND) in differentiated thyroid carcinoma (DTC) should only be considered in patients with high risk factors for lymph node (LN) metastasis due to the increases in the risk of postoperative complications. Our aim was to identify the risk factors for central lymph node metastasis (CLNM) in DTC.

METHOD

We searched PubMed, Scopus, Web of science, Cochrane library for eligible studies from inception to November 1, 2021 and a systematic review and meta-analysis were carried out to identify the risk factors for CLNM in DTC.

RESULTS

We included 41 studies with total of 27,741 patients in this study. The pooled results in this meta-analysis showed that these risk factors were significantly associated with CLNM: age < 45 years (odds ratio (OR) 1.64, 95% confidence interval (CI) 1.34-1.99, p < 0.00001), male sex (OR 1.73, 95% CI 1.54-1.93, p < 0.00001), multifocality (OR 1.87, 95% CI 1.59-2.19, p < 0.00001), bilateral disease (OR 1.43, 95% CI 1.15-1.78, p < 0.001), capsular invasion (OR 1.67, 95% CI 1.10-2.54, p < 0.02), lymphovascular invasion (OR 4.89, 95% CI 2.76-8.66, p < 0.00001) and extra-thyroidal extension (OR 2.43, 95% CI 1.97-3.00, p < 0.00001). In addition, young age (< 45 years), male sex, multifocality, and extra-thyroidal extension were significantly associated with large-volume CLNM in clinically N0 DTC patients. However, the presence of Hashimoto's thyroiditis was not a predictors of large-volume CLNM.

CONCLUSION

Young age (< 45 years), male sex, bilateral disease, multifocality, capsular invasion, lymphovascular invasion and extra-thyroidal extension are significantly associated with CLNM and pCND would be expected to have a higher yield in patients with these risk factors.

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.

Quantification and Pattern of Central Compartment Lymph Nodes in pN1a Papillary Thyroid Cancer Patients

Background: The background is to investigate the results of central compartment lymphadenectomy for pN1a papillary thyroid carcinoma (PTC) with regard to quantification and pattern of resected lymph nodes thereby providing basis for future compartment VI surgical intervention. Methods: The study comprised 443 pN1a PTC patients whose clinicopathological characteristics and central compartment lymphadenectomy results were compared and correlated with the primary thyroid cancer and lymph node metastasis (LNM) features. Ultimately, multivariate analysis was conducted to identify statistically significant impact factors for a high metastatic ratio (MR). Results: Dissected lymph nodes (DLNs) were more frequently identified in right level VI than left (P < .05) although there was no difference in in the number of resected metastatic lymph nodes (MLNs). Male sex, multifocality, extrathyroidal extension (ETE), and fewer DLNs were related to a high MR. There was a positive correlation between DLN and MLN, and a negative correlation between DLN and MR. Disease multifocality and ETE were identified more frequently in the left than the right thyroid lobe. Conclusion: The outcome of central compartment lymphadenectomy in pN1a PTC patients is associated with several factors, and a thorough dissection of lymph nodes improves the rate of metastatic lymph node resection.

Role of Sonographic Characteristics of Thyroid Bed Lesions Identified Following Thyroidectomy in the Diagnosis or Exclusion of Recurrent Cancer

Background US of the thyroid bed in patients with thyroid cancer often depicts small lesions, but it is unclear whether US characteristics of lesions can help predict cancer recurrence. Purpose To determine whether size or US features of lesions in the thyroid bed after thyroidectomy in conjunction with clinical features can help predict thyroid cancer recurrence. Materials and Methods With use of a US reporting database, all patients imaged between July 2006 and June 2016 with an indication of post-thyroidectomy follow-up were retrospectively identified. Recorded data included patient demographic characteristics; date of thyroidectomy; thyroid cancer type; presence, size, and US characteristics of thyroid bed lesions; and results of fine-needle aspiration (FNA). Images were reviewed for lesions that underwent FNA. The Fisher exact test was used for analysis. Results A total of 1885 patients (mean age ± standard deviation, 48 years ± 15; 1493 female patients) underwent 5732 US examinations. Most patients (1541 of 1885 [82%]) had papillary cancer. Overall, 3163 thyroid bed lesions were reported in 5732 US examinations (40.4%). More than half of these lesions (1860 of 3163 [58.8%]) had a maximum measurement of 6 mm or greater. FNA was performed in 144 of the 3163 lesions (4.6%), of which 61 (42.4%) were malignant, 33 (22.9%) were benign, and 50 (34.7%) were nondiagnostic. Five nondiagnostic lesions eventually proved malignant. Only the presence of punctate echogenicities in the lesion (28 of 61 malignant lesions [45.9%]; three of 33 benign lesions [9%]; 12 of 50 nondiagnostic lesions [24%]; P < .001) or the history of positive lymph nodes at thyroidectomy (44 of 61 malignant lesions [72.1%]; 10 of 33 benign lesions [30%]; 19 of 50 nondiagnostic lesions [38%]; P < .001) were associated with malignancy. Of 3019 thyroid bed lesions that did not undergo FNA, three were malignant and 2248 showed no growth at follow-up US ranging from 6 months to 10 years and are presumed benign. Of the 1303 lesions smaller than 6 mm, only two (0.2%) were malignant. Conclusion Small lesions are commonly found in the thyroid bed after thyroidectomy, and most are likely to be benign. Lesions smaller than 6 mm with no punctate echogenicities had a minimal risk for malignancy. © RSNA, 2021 See also the editorial by Grant and Malhi in this issue.

A meta-analysis on the effect of operation modes on the recurrence of papillary thyroid microcarcinoma

Whether total thyroidectomy reduces the recurrence rate in patients with papillary thyroid microcarcinoma (PTMC) is currently controversy. Conclusions of sporadic, inconsistent, and mono-institutional studies need a meta-analysis to evaluate. 525 relevant studies were obtained from initial search on PubMed, 511 studies were excluded by inclusion and exclusion criteria. Eligible data were extracted from each included study. The Odds ratios (ORs) and 95% confidence interval (CI) were used to assess the difference in the recurrence rates between PTMC patients treated with total thyroidectomy and non-total thyroidectomy. OR and 95% CI were calculated using a fixed-effects or a random-effects model. The Q statistic was used to evaluate homogeneity and Beggs test was used to assess publication bias. 14 studies meeting the inclusion criteria were included in this meta-analysis. The over all recurrence rates of pooled patients with total thyroidectomy and non-total thyroidectomy were 2.83% and 2.84% respectively. Primary random-effects model analysis showed, no significant difference of recurrence rates existed between two operation modes (OR = 0.732, 95% CI: 0.444 - 1.208), while, high heterogeneity among studies was found, I-squared index (I2) = 40.2%. After remove one study with high heterogeneity, the OR of the pooled recurrence rates of the total thyroidectomy and the non-total thyroidectomy groups was 0.786 (95% CI: 0.363 - 1.701), further suggesting no significant difference of the recurrence rate exists between two operation modes. Our meta-analysis demonstrated postoperative recurrence of PTMC is not reduced by total thyroidectomy, non-total thyroidectomy is also a good choice to treat PTMC patients.

Analysis of Risk Factors Contributing to Recurrence of Papillary Thyroid Carcinoma in Chinese Patients Who Underwent Total Thyroidectomy

BACKGROUND Thyroid cancer is a very common endocrine malignancy, with a rate of total thyroidectomy reported to be up to 27.8%. However, studies analyzing the risk factors that contribute to recurrence of papillary thyroid carcinoma (PTC) after total thyroidectomy in China are still scarce. MATERIAL AND METHODS A total of 536 patients with PTC who underwent total thyroidectomy were retrospectively analyzed. Patients were divided into 2 groups: patients with no recurrent tumor were included in group 1 and patients with tumor recurrence were included in group 2. RESULTS Of 536 patients, 65 patients (12.1%) developed a recurrence of PTC, and 471 patients (87.9%) did not have a recurrence. Univariate analysis indicated that male sex, age ≥50 years, tumor ≥1 cm, poor differentiation, lymph node metastasis, bilaterality, and multifocality may be related to PTC recurrence. Additionally, the results of the logistic regression analysis indicated that male sex, age ≥50 years, primary tumor ≥1 cm, poor dedifferentiation of the tumor, lymph node metastasis, and multifocality may be independent factors contributing to PTC recurrence. CONCLUSIONS Male sex, age more than 50 years, primary tumor larger than 1 cm, poor dedifferentiation of the primary tumor, lymph node metastasis, and multifocality were found to increase the risk of PTC recurrence in patients who underwent total thyroidectomy. Additionally, it is necessary to use strictly aggressive and extensive surgery, as well as close monitoring, after the operation.

Impact of microscopic extra-nodal extension (ENE) on locoregional recurrence following curative surgery for papillary thyroid carcinoma

BACKGROUND

The presence of microscopic extra-nodal extension (ENE) may increase locoregional recurrence (LRR) in papillary thyroid carcinoma (PTC). We aimed to evaluate the association between microscopic ENE, response to initial therapy and LRR risk following total thyroidectomy, therapeutic neck dissection, and radioactive iodine (RAI) ablation in PTC.

METHODS

Of the 369 eligible PTC patients, 264 (71.5%) did not have microscopic ENE (group I) while 105 (28.5%) did (group II). All presented with clinical nodal metastasis (cN1) and underwent therapeutic neck dissection and RAI ablation. Biochemical incompleteness meant post-ablation stimulated thyroglobulin (sTg) >10 ng/ml. Multivariate analyses were conducted to identify independent factors for LRR.

RESULTS

Biochemical incompleteness was significantly more common group II (43.8% vs. 17.4%, P < 0.05). The 10-year locoregional free-survival was significantly worse in group II than I (52.0% vs. 86.2%, P = 0.005). After adjusting for other significant factors, age <45 (P < 0.05), multifocality (P < 0.05), presence of ENE (P = 0.027) were independent risk factors of LRR. The number and size of positive lymph nodes were not independent factors.

CONCLUSIONS

Patients with microscopic ENE were significantly more likely to have biochemical incompleteness after initial therapy. After adjusting for other significant primary and nodal characteristics, microscopic ENE was an independent factor for LRR in patients with cN1. J. Surg. Oncol. 2016;113:526-531. © 2016 Wiley Periodicals, Inc.

Long-term oncologic outcome of robotic versus open total thyroidectomy in PTC: a case-matched retrospective study

PURPOSE

The role of the robot in thyroid surgery remains uncertain, and it is unclear whether robotic total thyroidectomy (R-TT) can be justified as a standard treatment for patients with thyroid cancer. This study compared the long-term operative results and oncologic outcomes of R-TT and conventional open TT (O-TT) after propensity score matching of the cohorts.

METHODS

This study retrospectively evaluated patients with papillary thyroid cancer (PTC) who underwent TT with central compartment node dissection (CCND) by a single surgeon in tertiary medical center. Of the 833 patients, 94 (11.3 %) were lost to follow-up. 245 (33.2 %) underwent R-TT, and 494 (66.8 %) underwent O-TT. The mean follow-up duration was 74 (range 61-91) months. Propensity score matching in age, gender, tumor size, extrathyroidal invasion, multiplicity, bilaterality, and TNM stage identified 206 pairs of patients. The long-term oncologic outcomes were assessed in the R-TT and O-TT groups before and after adjustment for baseline covariates.

RESULTS

After adjustment for baseline covariates, serum thyroglobulin (Tg) (p = 0.746) and anti-thyroglobulin antibody (TgAb) (p = 0.394) concentrations were similar in the two groups 5 years after surgery. Nine patients experienced locoregional recurrence, six in the O-TT and three in the R-TT group, with all recurrences in regional LNs. Disease-free survival (DFS) was similar in the R-TT and O-TT groups before matching (p = 0.890) and after adjustment for baseline covariates (p = 0.882).

CONCLUSION

This represents the first report of 5-year surgical outcomes in patients who underwent R-TT for thyroid cancer. Long-term oncologic quality was similar after R-TT and O-TT.

Prophylactic central lymph node dissection in cN0 patients with papillary thyroid carcinoma: A retrospective study in China

OBJECTIVE

The objective of the study was to assess the patterns of central cervical lymph node metastasis (CLNM) and evaluate the prophylactic central lymph node dissection (CLND) in papillary thyroid carcinoma (PTC) patients without clinical positive lymph nodes.

METHODS

We retrospectively reviewed 1555 patients with PTC between 2003 and 2008. Lymph node metastatic risk factors and the pattern of lymph node metastasis in PTC were studied using multivariate analysis.

RESULTS

Male patients, aged ≤ 45 years, the presence of extrathyroidal extension, and a primary tumor size > 10 mm were identified as risk factors for CLNM with odds ratios of 2.089, 2.417, 1.534, and 3.079, respectively. Among 1555 patients, 97 cases (6.24%) had transient hypoparathyroidism, and only two patients (0.13%) had permanent hypoparathyroidism. Recurrent laryngeal nerve injury after thyroidectomy occurred in 14 patients (0.9%). In this group, nine cases were transient injury and the remaining five were permanent. During the period of follow-up, ranging from 5 years to 10 years, 18 patients (1.16%) were found with locoregional recurrence.

CONCLUSION

Taken together, in terms of the high incidence rate of CLNM in cN0 PTC patients, we believe that routine prophylactic CLND is optimal for clinically negative PTC patients, during their first treatment, especially for those with risk factors for CLNM.