Patterns of lymph node metastases in papillary thyroid carcinoma: results from consecutive bilateral cervical lymph node dissection

How Many Nodes to Take? Lymph Node Ratio Below 1/3 Reduces Papillary Thyroid Cancer Nodal Recurrence

INTRODUCTION

Papillary thyroid carcinoma (PTC) accounts for the majority of thyroid malignancies; risk of PTC recurrence over a 30-year period is approximately 30%, of which 70% occur as nodal metastases. Patients with nodal disease who are treated with therapeutic dissection are at higher risk for recurrence, but optimal nodal yield has not been defined. We aim to determine variables predictive of nodal recurrence of PTC within the first 5 years of surgery, with a focus on lymph node ratio (LNR), to inform clinical decision-making.

METHODS

Retrospective chart review identified 41 patients with nodal recurrence of PTC and 284 without nodal recurrence following thyroid surgery from 2000 to 2015. Cohorts were compared with regards to clinical history, surgical findings, and tumor characteristics.

RESULTS

The fraction of the patients who underwent therapeutic central or lateral lymph node dissection was significantly higher in the nodal recurrence cohort. Maximum tumor size, presence of extrathyroidal extension, largest lymph node focus, LNR, postoperative thyroglobulin level, and administration of postoperative radioactive iodine were significantly increased in the PTC nodal recurrence group. LNR greater than 0.3 held the highest level of significance as a binary cutoff and captured the larger proportion of patients in the nodal recurrence cohort (68.3%).

CONCLUSION

This study demonstrates characteristics to help assess risk of nodal recurrence of PTC and suggests LNR of lower than 0.3 is optimal to reduce risk of recurrence. The next steps include cohort studies to validate findings and weight variable analysis to optimize the extent of surgical therapeutic dissection.

LEVEL OF EVIDENCE

4 Laryngoscope, 132:1883-1887, 2022.

Preoperative Sonographic and Clinicopathological Predictors for Solitary Lateral Neck Node Metastasis in Papillary Thyroid Carcinoma: A Retrospective Study

Background

Cervical lymph node metastasis (LNM) is an independent risk factor for poor prognosis of papillary thyroid carcinoma (PTC), but the scope of PTC lateral neck dissection (LND) is controversial. Solitary lateral lymph node metastasis (SLNM) is a special type of PTC with lateral LNM. Currently, study on the preoperative clinical characteristics of SLNM has been seldomly reported. This study evaluated the preoperative characteristics for predicting the SLNM of PTC.

Methods

We included 391 patients diagnosed with PTC between May 2011 and July 2017. Among those patients, 44 had SLNM and 347 had multiple lateral neck node metastasis (MLNM). The clinicopathologic characteristics and other central lymph node metastasis risk factors were retrospectively analyzed.

Results

Univariate analysis revealed that age and tumor size (≤1 cm) were significantly correlated with SLNM. In ROC curve analysis, the optimal cutoff age of preoperative predictors for the prediction of SLNM was 46.5 years (AUC=0.623, 0.536–0.710). Besides, the frequency and mean number of CLNM was significantly less in the SLNM than MLNM group. The oval and round tumor shape and well-defined margin of the tumor were more common in the SLNM group (p =0.001; p=0.024, respectively). In addition, multivariate analysis revealed that age ≥47, capsular invasion, no extrathyroidal extension, with central lymph node metastases and irregular shape were independent SLNM predictors of PTCs (odds ratio 2.386, 0.173, 0.284, 0.239, 0.188; 95% CI 1.07–5.140, 0.058–0.840, 0.066–0.926, 0.091–0.437, 0.167–0.864, respectively).

Conclusion

This study supported that SLNM is more likely to happen in PTC patients with age ≥47 years, capsular invasion, no extrathyroidal extension, with central lymph node metastases and irregular shape. That denotes, selective single level neck dissection can be considered as an alternative to systemic lateral neck dissection in those patients.

Individual prediction of lateral neck metastasis risk in patients with unifocal papillary thyroid carcinoma

INTRODUCTION

Much controversy exists over whether to perform lateral neck dissection (LND) on patients with papillary thyroid carcinoma (PTC). This study aimed to build predictive nomograms that could individually estimate lateral neck metastasis (LNM) risk and help determine follow up intensity.

PATIENTS AND METHODS

Unifocal PTC patients who underwent LND between April 2012 and August 2014 were identified. Clinical and pathological variables were retrospectively evaluated using univariate and stepwise multivariate logistic regression analysis. Variables that had statistical significance in final multivariate logistic models were chosen to build nomograms, which were further corrected using the bootstrap resampling method.

RESULTS

In all, 505 PTC patients were eligible for analysis. Among these, 178 patients (35.2%) had lateral neck metastasis. Two nomograms were generated: nomogram (c) and nomogram (c + p). Nomogram (c) incorporated four clinical variables: age, tumor size, tumor site, and extrathyroidal extension (ETE). It had a good discriminative ability, with a C-index of 0.79 (bootstrap-corrected, 0.78). Nomogram (c + p) incorporated two clinical variables and two pathological variables: tumor size, tumor site, extranodal extension (ENE), and number of positive nodes in the central compartment. Nomogram (c + p) showed an excellent discriminative ability, with a C-index of 0.86 (bootstrap-corrected, 0.85).

CONCLUSION

Two predictive nomograms were generated. Nomogram (c) is a clinical model, whereas nomogram (c + p) is a clinicopathological model. Each nomogram incorporates only four variables and can give an accurate estimate of LNM risk in unifocal PTC patients, which may assist clinicians in patient counseling and decision making regarding LND.

Bidirectional Approach of Video-Assisted Neck Surgery (BAVANS): Endoscopic complete central node dissection with craniocaudal view for treatment of thyroid cancer

INTRODUCTION

Endoscopic thyroidectomy is a well-established surgical technique that is mainly performed for benign thyroid disease. We considered that endoscopic surgery could also be widely indicated for the treatment of thyroid cancer. We herein describe our new bidirectional approach of video-assisted neck surgery (BAVANS) for complete central node dissection in endoscopic thyroid cancer surgery.

METHODS

BAVANS involves two different directional pathways to the cervical lesion. Before lymph node dissection, we perform endoscopic thyroidectomy via a conventional gasless precordial or axillary approach. After thyroidectomy, the surgeon repositions by the head of the patient and inserts three ports in front of the upper neck lesion in the submandibular area to approach the paratracheal lesion from an overhead-to-caudal direction.

RESULTS

BAVANS allows for an excellent craniocaudal view and easy access to the peritracheal lymph nodes. Sixteen patients with papillary thyroid cancer underwent BAVANS and progressed satisfactorily after surgery. Of those patients, eight underwent total or near total thyroidectomy, and five patients underwent bilateral central node dissection. The average number of retrieved lymph nodes with unilateral central node dissection was nine, which was higher than that achieved with conventional open surgery. All patients began oral intake within 5 h after surgery. Postoperative Horner syndrome occurred in one patient. No other complications were noted.

CONCLUSIONS

BAVANS is a very effective surgical procedure that many endoscopic surgeons can perform safely and easily. It has both a cosmetic advantage and excellent curability in endoscopic thyroid cancer surgery.

Clinical Experience With n-Butyl-2-Cyanoacrylate in Performing Lateral Neck Dissection for Metastatic Thyroid Cancer

Background Chyle leakage following lateral neck dissection (LND) is rare, but can induce metabolic disturbances, delay wound healing, and prolong hospitalization. n-Butyl-2-cyanoacrylate (NBCA) has been used to achieve hemostasis and seal tissues in several surgical settings. We here assessed whether application of NBCA to the thoracic duct area is effective in sealing chyle leakage. Methods The medical records of 163 patients who underwent total thyroidectomy with unilateral LND between March 2011 and September 2012 were reviewed. NBCA was applied to 84 patients and not applied to 79. Drainage volume, duration of hospital stay, and incidence of complications were compared between the 2 groups. Results The 2 groups were not different with regard to age, body weight, gender, primary tumor histology, and number of lateral neck nodes harvested. Mean hospital stay was significantly shorter (4.3 ± 1.8 vs 5.7 ± 3.0 days, P < .001), median total drainage volume was significantly smaller (270 mL; range: 97-931 mL vs 328 mL; range: 113-2636 mL; P < .001), and rate of chyle leakage was significantly lower (0% vs 6.3%, P = .025) in the NBCA than in the non-NBCA group. Conclusion NBCA application to the dissected area of the thoracic duct posterior to its angle of junction with the internal jugular and subclavian veins could be safe and effective in reducing surgical complications related to chyle leakage after LND.

Optimal Cut-Off Values of Lymph Node Ratio Predicting Recurrence in Papillary Thyroid Cancer

Regional lymph node (LN) metastasis has a significant impact for prediction of recurrence in patients with papillary thyroid cancers (PTC); however, the prognostic value of the lymph node ratio (LNR), which is defined as the ratio of the number of metastatic LNs to the total number of investigated LNs, is controversial. In this study, we determined the optimal cut-off values of LNRs for the prediction of recurrence in PTC patients.This large cohort study retrospectively evaluated 2294 patients who had undergone total thyroidectomy for PTC at a single institution from October 1985 to June 2009. The prediction probability of central LNR (cLNR, level VI) and total LNR (tLNR, levels II-VI) were estimated by binominal logistic regression analysis. Hazard ratios of the cut-off LNR values for cancer recurrence were calculated for relevant covariates using multivariate Cox regression analyses. Kaplan-Meier analyses were also utilized to assess the effects of estimated LNR cut-off values on recurrence-free survival (RFS).Of the 2294 patients, 138 (6.0%) presented cancer recurrence during the follow-up period (median duration = 107.1 months). The prediction probability indicated that LNRs of 0.4 and 0.5 for central LN and total LN, respectively, are optimal cut-off values for precise prediction with minimization of outliers. Multivariate Cox regression analyses revealed that cLNR ≥0.4 was independently predictive of recurrence in patients with N0 and N1a PTCs (hazard ratio [HR]: 7.016, 95% confidence interval [CI]: 3.72-12.986, P < 0.001) and that tLNR ≥0.5 indicated a significantly increased risk of recurrence in patients with N1b PTCs (HR: 2.372, 95% CI: 1.458-3.860, P < 0.001). In addition, Kaplan-Meier analyses clearly demonstrated that these LNR cut-off values are precisely operational in RFS estimation.The cut-off LNR values of 0.4 and 0.5 for cLNR and tLNR, respectively, were identified. Risk stratification combined with these LNR cut-off values may prove useful to determine treatment and follow-up strategies for PTC patients.

Diagnostic Efficacy of Ultrasonographic Characteristics of Thyroid Carcinoma in Predicting Cervical Lymph Node Metastasis

The goals of this study were to determine the ultrasonographic characteristics of thyroid carcinoma (TC) and to explore the diagnostic efficacy of these ultrasonographic characteristics in predicting cervical lymph node metastasis (LNM). From June 2012 to June 2014, a total of 186 TC patients were recruited from the Central Hospital of Chengde City, Hebei, China. We divided them into two groups: the metastatic group comprised 129 nodules (n = 86), and the non-metastatic group 117 nodules (n = 100). Univariate and multivariate analyses were used to evaluate the relationship between ultrasonographic characteristics and cervical LNM. Spectral Doppler ultrasound was employed to estimate peak systolic velocity, pulsatility index and resistive index. Receiver operating characteristic curves were drawn to evaluate the efficacy of ultrasonographic characteristics in predicting cervical LNM. The sensitivity, specificity, positive predictive value and negative predictive value of ultrasonographic diagnosis were 81.40% (105/129), 92.32% (108/117), 92.11% (105/114) and 81.82% (108/132), respectively. Cervical LNM in TC frequently occurred at the cervical level VI (37.98%) and was located mainly in the middle pole (46.51%) or lower pole (41.09%). Peak systolic velocity and resistive index values were significantly higher in the metastatic group than in the non-metastatic group (both p < 0.001). Multivariate analysis revealed that nodular diameter, capsular invasion, microcalcification and flow grade were risk factors for TC patients with cervical LNMs (all p < 0.05). Furthermore, receiver operating characteristic curve analysis revealed that nodular diameter, capsular invasion, microcalcification and flow grade had excellent accuracy in predicting cervical LNM. We conclude that ultrasonographic characteristics of TC, including maximum nodular diameter, capsular invasion, microcalcification and flow grade, may predict cervical LNM.

The Effect of Thyroiditis on the Yield of Central Compartment Lymph Nodes in Patients with Papillary Thyroid Cancer

BACKGROUND

In patients who have undergone thyroidectomy and central compartment neck dissection (CCND) for papillary thyroid cancer (PTC), visualization of enlarged lymph nodes may lead to more extensive CCND. This study sought to determine the effect of patient age and the presence of thyroiditis on the number of malignant and total lymph nodes resected in patients who underwent CCND for PTC.

METHODS

This retrospective review examined a prospective database of patients who underwent total thyroidectomy and CCND for PTC between April 2009 and June 2013 and had thyroiditis on the final pathology. The patients were categorized into age groups by decade (18-29, 30-39, 40-49, 50-59, and ≥60 years) and compared with a control group of patients matched by age, gender, and tumor size.

RESULTS

Of 74 patients with thyroiditis, 64 (87 %) were women. The median age of the patients was 47.5 years (range 18.2-72.0 years). The patients with thyroiditis had more lymph nodes resected than those without thyroiditis (median 11 vs 7; p < 0.01). However, these patients had fewer malignant lymph nodes (median 0 vs 1.5; p = 0.06), resulting in a lower lymph node ratio (0 vs 0.18; p = 0.02) for the entire cohort, but particularly for the youngest (18-29 years) and oldest (≥60 years) age groups.

CONCLUSIONS

Patients with thyroiditis and PTC who underwent CCND had more lymph nodes resected but a had lower proportion of metastatic lymph nodes than those without thyroiditis. Given the relatively low yield of malignant cervical lymphadenopathy, a more judicious approach to CCND might be considered, particularly for the youngest and oldest patients with PTC and thyroiditis.

Increasing thyroid cancer rate and the extent of thyroid surgery in Korea

BACKGROUND

It is evident that the rate of thyroid cancer is increasing throughout the world. One reason is increased detection of preclinical small cancers. However, it is not clear whether the increase in thyroid cancer rate is reducing the extent of thyroid surgeries. The purpose of this study was to evaluate the thyroid cancer rate and analyze recent changes in the extent of thyroid cancer surgeries in Korea.

METHODS

An observational study was conducted using data from Korea's Health Insurance Review and Assessment Service (HIRAS) for thyroidectomy with/without neck dissection, with 228,051 registered patients between 2007 and 2011. Data were categorized by the extent of surgery: unilateral thyroidectomy without neck dissection (UT), bilateral thyroidectomy or radical thyroidectomy without neck dissection (TT), any thyroidectomy with unilateral selective neck dissection (SND), any thyroidectomy with unilateral modified radical neck dissection (MRND), any thyroidectomy with unilateral radical neck dissection (RND), and any thyroidectomy with bilateral neck dissection (BND). Annual rate difference for each surgery was analyzed with a linear by linear association.

RESULTS

The absolute numbers of total thyroid surgeries (UT+TT+SND+MRND+RND+BND) were increased from 28539 to 61481. The proportion of patients who underwent only thyroidectomy without neck dissection (UT+TT) decreased from 67.30% to 60.50%, whereas the proportion of patients who underwent neck dissection (SND+MRND+RND+BND) increased from 32.70% to 39.50% during the 5-year study period.

CONCLUSION

Despite the increase in rate of thyroid cancer due to earlier detection, increased rate of neck dissection was noted.

Level 7 disease does not confer worse outcome than level 6 disease in differentiated thyroid cancer

BACKGROUND

Level 7 nodal disease increases patients from N1a to N1b in the American Joint Committee on Cancer (AJCC) TNM classification of differentiated thyroid cancers (DTCs). This results in upstaging of patients older than 45 years of age from stage III to IV. Our objective was to determine if patients with level 7 disease had poorer outcome in comparison to patients with isolated level 6 disease.

METHODS

A total of 599 patients with DTC limited to the central neck (level 6 and 7) were identified from an institutional database. Patients with N1b disease due to lateral compartment (level 1-5) involvement or M1 disease were excluded. Fifty-seven patients had positive level 7 disease, and 542 patients had nodal disease limited to level 6. Disease-specific survival (DSS) and recurrence-free survival (RFS) were calculated for each group.

RESULTS

Median age was 41 years (range 12-91) and follow-up was 61 months (range 1-330). There were no disease-specific deaths at 5 years. Among patients with level 6 disease at presentation, there were 42 nodal recurrences, and among patients with level 7 disease, there were two recurrences. There were no differences in overall RFS between patients with level 6 or 7 disease (5-year RFS 90.7 vs. 98.2 %, respectively; p = 0.096).

CONCLUSIONS

Our results suggest that N1b disease due to level 7 disease does not confer worse DSS or RFS compared with patients with level 6 disease only. Classifying all central neck disease (levels 6 and 7) into the N1a category, and reserving the N1b classification only for patients with lateral neck disease may be more reflective of prognosis.

Pathologic reporting of lymph node metastases in differentiated thyroid cancer: a call to action for the College of American Pathologists

Lymph nodes in differentiated thyroid cancer have many different histomorphologic features. The current AJCC staging system does not distinguish between different lymph node characteristics and is based entirely on the presence of metastatic disease to upstage pN0 to pN1. However, clinicians involved in the management of thyroid cancer recognize that there is a difference in the clinical significance of finding macroscopic versus microscopic nodes. There appears to be a difference in disease biology that allows lymph nodes to reach different sizes and to manifest disease extension outside the capsule, which has led clinicians, and even clinical practice guidelines, to stratify nodal metastases on the basis of these features. The inherent presumption is that all lymph node metastases in differentiated thyroid cancer do not have the same clinical significance with respect to the risk of recurrence and the risk of death. However, the College of American Pathology (CAP) has not mandated that pathologists include these findings as part of their standard reporting protocol in thyroid cancer. In order to arm clinicians with the tools to design clinical trials and to make important patient management decisions in the presence of lymph node metastases, it is imperative that the CAP adopt a strategy for more detailed reporting that is similar to the protocol currently utilized in breast cancer pathologic reporting.

The pros and cons of prophylactic central neck dissection in papillary thyroid carcinoma

Prophylactic central neck dissection (pCND) for management of papillary thyroid carcinoma (PTC) is controversial. Compared to many malignancies, PTC has a high overall survival but local recurrence due to lymph node metastases continue to present management challenges. Unlike lateral cervical nodal metastasis metastasis, central neck nodal metastasis are unable to be reliably detected clinically or radiologically at pre-operative assessment. Residual disease (recurrent or persistent) typically requires re-operative surgery in the central compartment, which carries a heightened risk of significant morbidity. These nodal groups can be accessed during the index thyroidectomy for PTC. Thus, pCND offers potential to reduce the rates of recurrence and the need for re-operative surgery in the central neck. This benefit needs to be balanced with the potential morbidity risk from pCND itself at the index resection. This review will discuss the advantages and disadvantages of pCND with regard to long-term outcomes and potential morbidity. The rationale of pCND will be discussed, along with the indications for ipsilateral and contralateral pCND, the role of re-operative surgery for recurrence and the use of selective versus routine pCND. Strategies to select higher risk patients for pCND with the use of molecular markers will be addressed, along with a discussion of quality of life (QoL) research in PTC.

Solitary lateral neck node metastasis in papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) is associated with a high incidence of regional node metastasis, but the patterns of lateral neck node metastasis (LNM) vary. Occasionally, a solitary LNM (SLNM) is seen in PTC patients. We therefore assessed whether selective single level node dissection is appropriate in PTC patients with SLNM.

Methods

We retrospectively reviewed the medical records of 241 PTC patients who underwent total thyroidectomy with central neck dissection plus ipsilateral internal jugular node dissection (level II to IV) between January 2010 and December 2011. Of these patients, 51 had SLNM and 190 had multiple LNM (MLNM). The clinicopathologic characteristics of the two groups were compared.

Results

Age, gender ratio, and numbers of lateral neck nodes harvested (29.4 ± 11.0 versus 30.3 ± 9.5; P = 0.574) were similar in the SLNM and MLNM groups. Mean primary tumor size was significantly smaller in the SLNM than in the MNLM group (1.03 cm versus 1.35 cm; P = 0.037). The proportion of patients with primary tumor ≤ 1 cm was significantly greater in the SLNM group (60.8% versus 38.4%; P = 0.006), whereas the proportion with maximal node size ≤ 0.7 cm (28.9% versus 73.3%; P <0.001) and the proportion with capsular invasion (62.7% versus 83.7%, P = 0.002) were significantly lower in the SLNM than in the MLNM group.

Conclusions

Selective single level neck dissection can be considered as an alternative to systemic lateral neck dissection in PTC patients with SLNM, maximal metastatic node size ≤ 0.7 cm, and no extrathyroidal invasion.

Classification of locoregional lymph nodes in medullary and papillary thyroid cancer

BACKGROUND

Among the various thyroid malignancies, medullary and papillary thyroid carcinomas are characterized by predominant locoregional lymph node metastases that may cause morbidity and affect patient survival. Although lymph node metastases are frequently detected, the optimal strategy aiming at the removal of all tumor tissues while minimizing the associated surgical morbidity remains a matter of debate.

PURPOSE

A uniform consented terminology and classification is a precondition in order to compare results of the surgical treatment of thyroid carcinomas. While the broad distinction between central and lateral lymph node groups is generally accepted, the exact boundaries of these neck regions vary significantly in the literature. Four different classification systems are currently used. The classification system of the American Head and Neck Society and the corresponding classification system of the Union for International Cancer Control (UICC) are based on observations of squamous cell carcinomas and appointed to needs of head and neck surgeons. The classification of the Japanese Society for Thyroid Diseases and the compartment classification acknowledge the distinctive pattern of metastasis in thyroid carcinomas.

CONCLUSIONS

Comparison of four existing classification systems reveals underlying different treatment concepts. The compartment system meets the necessities of thyroid carcinomas and is used worldwide in studies describing the results of lymph node dissection. Therefore, the German Association of Endocrine Surgery has recommended using the latter system in their recently updated guidelines on thyroid carcinoma.

Surgical management of the lateral neck compartment for metastatic thyroid cancer

PURPOSE OF REVIEW

The lateral neck compartment is the second most frequent target region for metastatic papillary thyroid cancer (PTC) and medullary thyroid cancer (MTC). Lateral lymph node metastases are associated with locoregional recurrence and, when they involve either side of the neck, with mediastinal and distant metastases.

RECENT FINDINGS

For tumors originating from the upper thyroid pole, the first nodal basin is not invariably the central compartment (as for primaries arising from the inferior thyroid pole) but often the upper part of the ipsilateral lateral compartment. Lymph node dissection of the first basin may differ depending on the location of the primary tumor. Involvement of the contralateral lateral compartment is seen in PTC with extensive central compartment involvement, and in MTC with preoperative basal calcitonin levels more than 200  pg/ml (normal limit <10  pg/ml).

SUMMARY

After lateral lymph node dissection for metastatic thyroid cancer, dysfunction of lateral neck nerves is fairly common. This observation underpins the importance of striking a balance between oncological benefit and surgical risk. Lateral lymph node dissection may be warranted for an upper thyroid pole primary, for a tumor with extensive involvement of the central compartment, and for an MTC with increased basal calcitonin level of 20-200  pg/ml (ipsilateral dissection) or more than 200  pg/ml (bilateral dissection).

The extent of lateral lymph node dissection in differentiated thyroid cancer in the N+ neck

The management of the lateral neck in metastatic differentiated thyroid cancer (DTC) varies widely. Most groups advocate dissection of nodal levels II-IV but many perform a more extensive dissection. We aimed to asses whether there was any evidence for a modified radical neck dissection over a selective neck dissection by looking at the extent to which DTC metastases to levels I and V. We performed a review of the current literature including adult and paediatric patients who underwent a lateral neck dissection for metastatic DTC. The primary endpoint was histological confirmation of metastases in nodal levels I and V. 650 abstracts were identified and reviewed. 23 papers were included in the study. The incidence of level V metastases during routine level V dissection in patients with DTC is 20 % and the incidence of level I metastases during routine level I dissection in patients with DTC is 8 %. Histologically proven metastases were found in 22.5 % of level V neck dissection of which 2.5 % were pre-operatively suspected of metastases. 20 % had histologically proven metastases to level I of which 12 % were pre-operatively suspected of metastases. Our study has shown a 20 % incidence of level V metastases in the N+ neck suggesting that level V should be part of a planned neck dissection. Evidence is lacking for routine dissection of level I. A future prospective study is required to asses the question of risk factors for lateral nodal metastases, recurrence and survival.

Disease outcomes and nodal recurrence in patients with papillary thyroid cancer and lateral neck nodal metastases

BACKGROUND

The prognostic influence of lateral neck nodal metastases present at the time of diagnosis of papillary thyroid cancer (PTC) remains controversial. This study aims to document disease outcomes and nodal recurrence rates in such patients.

METHODS

Patients with PTC and lateral neck nodal metastases who underwent concurrent total thyroidectomy, central and lateral compartment neck dissection between 2000 and 2010 were identified from the prospectively maintained surgical databases of The University of Sydney and University of Wisconsin Endocrine Surgical Units. Disease outcomes and nodal recurrence rates were compared at 12 months post-operatively and in longer-term follow-up.

RESULTS

During this 11-year period, 121 patients were identified. Mean age was 45 years; 58% were female and 98% underwent post-operative radioactive iodine ablation. At a median follow-up of 31 months (range 12-140), there were no disease-specific deaths and disease-free survival (defined by stimulated serum thyroglobulin (Tg) < 2.0 μg/L, negative clinical and radiological examination) was 66%. Of the 50 patients with persistently elevated Tg measured 12 months post-operatively, 15 developed clinical lateral neck nodal recurrence. All have undergone re-operative surgery. Elevated stimulated Tg at 12 months post-operatively and a nodal ratio of >30% were significantly associated with an increased risk of lateral neck nodal recurrence.

CONCLUSION

With total thyroidectomy, formal compartmental neck dissection and radioactive iodine treatment, disease-free survival can be achieved in the majority of patients with PTC and synchronous lateral neck nodal metastases. A persistently elevated Tg post-operatively and a high ratio of metastatic nodes identify patients at increased risk of locoregional recurrence.

Significance of size of lymph node metastasis on postsurgical stimulated thyroglobulin levels after prophylactic unilateral central neck dissection in papillary thyroid carcinoma

Background

The prognostic significance of size of central lymph node metastasis (CLNM) in papillary thyroid carcinoma (PTC) remains unknown. Because postsurgical detectable stimulated thyroglobulin (DsTg) after radioiodine ablation may imply persistent or recurrent disease, we evaluated the association between size of CLNM and rate of DsTg in patients with PTC who underwent unilateral prophylactic central neck dissection.

Methods

To be eligible for analysis, the prophylactic central neck dissection specimen with <3 central lymph nodes (CLNs) or size of CLNM ≥1 cm as measured under the microscope was excluded. Of 132 specimens, 89 (67.4 %) were eligible. Forty patients (44.9 %) had no metastasis or pN0, 20 (22.5 %) had micrometastasis (<2 mm) or pN1mic and 29 (32.6 %) had macrometastasis (≥2 mm) or pN1mac. Postablation sTg level was measured 9 months after surgery. A multivariable analysis was conducted to identify independent factors for postablation DsTg.

Results

Larger-sized CLNM correlated significantly with younger age (p = 0.028), greater number of CLN retrieved (p = 0.016), greater number of metastatic CLN excised (p < 0.001), higher metastatic CLN ratio (p = 0.006) and postablation sTg level (p = 0.012). In the multivariable analysis, after adjusting for tumor size and metastatic CLN ratio, size of CLNM was an independent predictor of postablation DsTg (odds ratio 1.56, 95 % confidence interval 1.09–2.24, p = 0.015). Relative to pN0, the odds ratios for postablation DsTg in pN1mic and pN1mac were 2.53 (95 % confidence interval 0.35–19.00, p = 0.351) and 5.81 (95 % confidence interval 1.22–27.70, p = 0.027), respectively.

Conclusions

Size of CLNM was an independent factor for DsTg 9 months after surgery. Patients with pN1mac were almost 6 times more likely to have postablation DsTg than those with pN0 or pN1mic.

Significance of metastatic lymph node ratio on stimulated thyroglobulin levels in papillary thyroid carcinoma after prophylactic unilateral central neck dissection

Background

Prognostic significance of metastatic central lymph node ratio (CLNR) in papillary thyroid carcinoma (PTC) remains unknown. Because postsurgical detectable stimulated thyroglobulin (DsTg) after radioiodine ablation may imply persistent or recurrent disease, we evaluated the association between CLNR and rate of DsTg in patients with PTC who underwent unilateral prophylactic central neck dissection.

Methods

To be eligible for analysis, the prophylactic central neck dissection specimen had to contain ≥3 central lymph nodes (CLNs) with ≥1 harboring metastasis. Of 129 specimens, 51 (39.5%) were eligible. CLNR was calculated as follows: (number of metastatic CLNs/number of CLNs retrieved) × 100. They were categorized into group 1 (CLNR <33.34%) (n = 14), group 2 (CLNR 33.34–66.67%) (n = 15), and group 3 (CLNR >66.67%) (n = 22). Postablation sTg level was measured 6 months after radioiodine ablation. A multivariate analysis was conducted to identify factors for postablation DsTg.

Results

Young age, palpable neck swelling, large tumor size, advanced tumor, node, metastasis system (TNM) stage, and large number of metastatic CLNs were significantly associated with high CLNR (P < 0.05). Compared to groups 1 and 2, group 3 had significantly higher DsTg rate (P = 0.018). Those who developed subsequent recurrence had significantly higher DsTg rate than those who did not (100% vs. 39.1%, P = 0.013). In the multivariate analysis for postablative DsTg, after adjusting for age, palpable neck swelling, tumor size, TNM stage, and number of metastatic CLNs, CLNR was the only independent factor (odds ratio 1.15, 95% confidence interval 1.01–1.31, P = 0.036).

Conclusions

A higher CLNR was associated with a higher rate of postablative DsTg; this may imply higher future recurrence rate.

Insignificance of prophylactic upper mediastinal lymph node dissection by sternotomy for papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is characterized by extensive lymph node metastases. A considerably high frequency of lymph node metastases in the upper mediastinal compartment (UMC) has been reported. However, the significance of prophylactic upper mediastinal lymph node dissection (UMLND) by sternotomy as an appropriate therapeutic option has not yet been clarified. Thirty-three patients who underwent prophylactic UMLND by sternotomy for PTC at our institution between 1980 and 1987 (group A) were analyzed. One hundred and fifty-one consecutive patients with PTC who underwent curative total thyroidectomy, bilateral modified radical neck dissection, and UMLND by collar incision as initial treatment between 1990 and 1999 (group B) were analyzed as controls. The patterns of lymph node metastases in the cervical compartment of these two groups were comparable; distribution of lymph node metastases in UMC was considerably less frequent than in other compartments. Clinical relapse in UMC was not observed in both groups. No significant difference in disease specific survival or relapse free survival between group A and B was observed. The lack of clinical relapse in UMC in group B indicates that most of the lymph node metastases in this compartment could be resected by the conventional collar incision or most microscopic lymphatic metastases could remain dormant as with lateral microscopic node metastases. Thus, upper mediastinal lymph node metastases requiring sternotomy to resect in curable patients with PTC could be less frequent. Prophylactic UMLND by sternotomy for PTC is discouraged from a clinical view point.